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1.
J Vis Exp ; (206)2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38738900

ABSTRACT

Bacterial cytoskeletal proteins such as FtsZ and MreB perform essential functions such as cell division and cell shape maintenance. Further, FtsZ and MreB have emerged as important targets for novel antimicrobial discovery. Several assays have been developed to identify compounds targeting nucleotide binding and polymerization of these cytoskeletal proteins, primarily focused on FtsZ. Moreover, many of the assays are either laborious or cost-intensive, and ascertaining whether these proteins are the cellular target of the drug often requires multiple methods. Finally, the toxicity of the drugs to eukaryotic cells also poses a problem. Here, we describe a single-step cell-based assay to discover novel molecules targeting bacterial cytoskeleton and minimize hits that might be potentially toxic to eukaryotic cells. Fission yeast is amenable to high-throughput screens based on microscopy, and a visual screen can easily identify any molecule that alters the polymerization of FtsZ or MreB. Our assay utilizes the standard 96-well plate and relies on the ability of the bacterial cytoskeletal proteins to polymerize in a eukaryotic cell such as the fission yeast. While the protocols described here are for fission yeast and utilize FtsZ from Staphylococcus aureus and MreB from Escherichia coli, they are easily adaptable to other bacterial cytoskeletal proteins that readily assemble into polymers in any eukaryotic expression hosts. The method described here should help facilitate further discovery of novel antimicrobials targeting bacterial cytoskeletal proteins.


Subject(s)
Anti-Bacterial Agents , Bacterial Proteins , Cytoskeletal Proteins , Schizosaccharomyces , Schizosaccharomyces/drug effects , Schizosaccharomyces/metabolism , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/antagonists & inhibitors , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Bacterial Proteins/metabolism , Drug Evaluation, Preclinical/methods
2.
Life Sci Alliance ; 7(7)2024 Jul.
Article in English | MEDLINE | ID: mdl-38719752

ABSTRACT

Septins are cytoskeletal proteins that participate in cell adhesion, migration, and polarity establishment. The septin subunit SEPT9 directly interacts with the single LIM domain of epithelial protein lost in neoplasm (EPLIN), an actin-bundling protein. Using a human SEPT9 KO fibroblast cell line, we show that cell adhesion and migration are regulated by the interplay between both proteins. The low motility of SEPT9-depleted cells could be partly rescued by increased levels of EPLIN. The normal organization of actin-related filopodia and stress fibers was directly dependent on the expression level of SEPT9 and EPLIN. Increased levels of SEPT9 and EPLIN enhanced the size of focal adhesions in cell protrusions, correlating with stabilization of actin bundles. Conversely, decreased levels had the opposite effect. Our work thus establishes the interaction between SEPT9 and EPLIN as an important link between the septin and the actin cytoskeleton, influencing cell adhesion, motility, and migration.


Subject(s)
Cell Adhesion , Cell Movement , Fibroblasts , Focal Adhesions , LIM Domain Proteins , Septins , Humans , Septins/metabolism , Septins/genetics , Cell Movement/genetics , Fibroblasts/metabolism , LIM Domain Proteins/metabolism , LIM Domain Proteins/genetics , Focal Adhesions/metabolism , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/genetics , Pseudopodia/metabolism , Actin Cytoskeleton/metabolism , Cell Line , Actins/metabolism , Stress Fibers/metabolism
3.
Int J Mol Sci ; 25(9)2024 May 02.
Article in English | MEDLINE | ID: mdl-38732188

ABSTRACT

The cytoskeleton plays a pivotal role in maintaining the epithelial phenotype and is vital to several hallmark processes of cancer. Over the past decades, researchers have identified the epithelial protein lost in neoplasm (EPLIN, also known as LIMA1) as a key regulator of cytoskeletal dynamics, cytoskeletal organization, motility, as well as cell growth and metabolism. Dysregulation of EPLIN is implicated in various aspects of cancer progression, such as tumor growth, invasion, metastasis, and therapeutic resistance. Its altered expression levels or activity can disrupt cytoskeletal dynamics, leading to aberrant cell motility and invasiveness characteristic of malignant cells. Moreover, the involvement of EPLIN in cell growth and metabolism underscores its significance in orchestrating key processes essential for cancer cell survival and proliferation. This review provides a comprehensive exploration of the intricate roles of EPLIN across diverse cellular processes in both normal physiology and cancer pathogenesis. Additionally, this review discusses the possibility of EPLIN as a potential target for anticancer therapy in future studies.


Subject(s)
Neoplasms , Humans , Neoplasms/metabolism , Neoplasms/pathology , Animals , Cytoskeletal Proteins/metabolism , Cytoskeleton/metabolism , Cell Movement , Cell Proliferation
4.
J Cell Biol ; 223(9)2024 Sep 02.
Article in English | MEDLINE | ID: mdl-38781029

ABSTRACT

The mitochondria-ER-cortex anchor (MECA) forms a tripartite membrane contact site between mitochondria, the endoplasmic reticulum (ER), and the plasma membrane (PM). The core component of MECA, Num1, interacts with the PM and mitochondria via two distinct lipid-binding domains; however, the molecular mechanism by which Num1 interacts with the ER is unclear. Here, we demonstrate that Num1 contains a FFAT motif in its C-terminus that interacts with the integral ER membrane protein Scs2. While dispensable for Num1's functions in mitochondrial tethering and dynein anchoring, the FFAT motif is required for Num1's role in promoting mitochondrial division. Unexpectedly, we also reveal a novel function of MECA in regulating the distribution of phosphatidylinositol-4-phosphate (PI(4)P). Breaking Num1 association with any of the three membranes it tethers results in an accumulation of PI(4)P on the PM, likely via disrupting Sac1-mediated PI(4)P turnover. This work establishes MECA as an important regulatory hub that spatially organizes mitochondria, ER, and PM to coordinate crucial cellular functions.


Subject(s)
Endoplasmic Reticulum , Mitochondria , Phosphatidylinositol Phosphates , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Cell Membrane/metabolism , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Mitochondria/metabolism , Mitochondria/genetics , Mitochondrial Dynamics , Phosphatidylinositol Phosphates/metabolism , Protein Binding , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae Proteins/genetics
5.
Exp Neurol ; 377: 114805, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38729552

ABSTRACT

Staufen-1 (STAU1) is a double-stranded RNA-binding protein (RBP) involved in a variety of pathological conditions. In this study, we investigated the potential role of STAU1 in Alzheimer's disease (AD), in which two hallmarks are well-established as cerebral ß-amyloid protein (Aß) deposition and Tau-centered neurofibrillary tangles. We found that STAU1 protein level was significantly increased in cells that stably express full-length APP and the brain of APP/PS1 mice, an animal model of AD. STAU1 knockdown, as opposed to overexpression, significantly decreased the protein levels of ß-amyloid converting enzyme 1 (BACE1) and Aß. We further found that STAU1 extended the half-life of the BACE1 mRNA through binding to the 3' untranslated region (3'UTR). Transcriptome analysis revealed that STAU1 enhanced the expression of growth arrest and DNA damage 45 ß (GADD45B) upstream of P38 MAPK signaling, which contributed to STAU1-induced regulation of Tau phosphorylation at Ser396 and Thr181. Together, STAU1 promoted amyloidogenesis by inhibiting BACE1 mRNA decay, and augmented Tau phosphorylation through activating GADD45B in relation to P38 MAPK. Targeting STAU1 that acts on both amyloidogenesis and tauopathy may serve as an optimistic approach for AD treatment.


Subject(s)
Amyloid Precursor Protein Secretases , Aspartic Acid Endopeptidases , RNA-Binding Proteins , tau Proteins , Animals , tau Proteins/metabolism , tau Proteins/genetics , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/genetics , Mice , Phosphorylation , Amyloid Precursor Protein Secretases/metabolism , Amyloid Precursor Protein Secretases/genetics , Aspartic Acid Endopeptidases/metabolism , Aspartic Acid Endopeptidases/genetics , Humans , Mice, Transgenic , Amyloid beta-Peptides/metabolism , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Alzheimer Disease/genetics , Cells, Cultured , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/genetics
6.
J Psychiatr Res ; 174: 84-93, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38626565

ABSTRACT

Schizophrenia (SCZ) represents a set of enduring mental illnesses whose underlying etiology remains elusive, posing a significant challenge to public health. Previous studies have shown that the neurodevelopmental process involving small molecules such as miRNA and mRNA is one of the etiological hypotheses of SCZ. We identified and verified that miR-30e-3p and ABI1 can be used as biomarkers in peripheral blood transcriptome sequencing data of patients with SCZ, and confirmed the regulatory relationship between them. To further explore their involvement, we employed retinoic acid (RA)-treated SH-SY5Y differentiated cells as a model system. Our findings indicate that in RA-induced SH-SY5Y cells, ABI1 expression is up-regulated, while miR-30e-3p expression is down-regulated. Functionally, both miR-30e-3p down-regulation and ABI1 up-regulation promote apoptosis and inhibit the proliferation of SH-SY5Y cells. Subsequently, the immunofluorescence assay detected the expression location and abundance of the neuron-specific protein ß-tubulinIII. The expression levels of neuronal marker genes MAPT, TUBB3 and SYP were detected by RT-qPCR. We observed that these changes of miR-30e-3p and ABI1 inhibit the neurite growth of SH-SY5Y cells. Rescue experiments further support that ABI1 silencing can correct miR-30e-3p down-regulation-induced SH-SY5Y neurodevelopmental defects. Collectively, our results establish that miR-30e-3p's regulation of neurite development in SH-SY5Y cells is mediated through ABI1, highlighting a potential mechanism in SCZ pathogenesis.


Subject(s)
Biomarkers , MicroRNAs , Schizophrenia , Humans , MicroRNAs/blood , MicroRNAs/genetics , Schizophrenia/blood , Schizophrenia/metabolism , Cell Line, Tumor , Biomarkers/blood , Biomarkers/metabolism , Neurites/drug effects , Tretinoin/pharmacology , Tubulin/metabolism , Apoptosis/drug effects , Apoptosis/physiology , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/genetics , Neuroblastoma
7.
EMBO Rep ; 25(5): 2418-2440, 2024 May.
Article in English | MEDLINE | ID: mdl-38605277

ABSTRACT

Microcephaly is a common feature in inherited bone marrow failure syndromes, prompting investigations into shared pathways between neurogenesis and hematopoiesis. To understand this association, we studied the role of the microcephaly gene Mcph1 in hematological development. Our research revealed that Mcph1-knockout mice exhibited congenital macrocytic anemia due to impaired terminal erythroid differentiation during fetal development. Anemia's cause is a failure to complete cell division, evident from tetraploid erythroid progenitors with DNA content exceeding 4n. Gene expression profiling demonstrated activation of the p53 pathway in Mcph1-deficient erythroid precursors, leading to overexpression of Cdkn1a/p21, a major mediator of p53-dependent cell cycle arrest. Surprisingly, fetal brain analysis revealed hypertrophied binucleated neuroprogenitors overexpressing p21 in Mcph1-knockout mice, indicating a shared pathophysiological mechanism underlying both erythroid and neurological defects. However, inactivating p53 in Mcph1-/- mice failed to reverse anemia and microcephaly, suggesting that p53 activation in Mcph1-deficient cells resulted from their proliferation defect rather than causing it. These findings shed new light on Mcph1's function in fetal hematopoietic development, emphasizing the impact of disrupted cell division on neurogenesis and erythropoiesis - a common limiting pathway.


Subject(s)
Cell Cycle Proteins , Cyclin-Dependent Kinase Inhibitor p21 , Erythropoiesis , Mice, Knockout , Microcephaly , Tumor Suppressor Protein p53 , Animals , Erythropoiesis/genetics , Microcephaly/genetics , Microcephaly/pathology , Mice , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Cyclin-Dependent Kinase Inhibitor p21/genetics , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism , Mutation , Anemia, Macrocytic/genetics , Anemia, Macrocytic/pathology , Anemia, Macrocytic/metabolism , Cell Differentiation/genetics , Erythroid Precursor Cells/metabolism
8.
Transl Psychiatry ; 14(1): 197, 2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38670959

ABSTRACT

Alcohol use and anxiety disorders occur in both males and females, but despite sharing similar presentation and classical symptoms, the prevalence of alcohol use disorder (AUD) is lower in females. While anxiety is a symptom and comorbidity shared by both sexes, the common underlying mechanism that leads to AUD and the subsequent development of anxiety is still understudied. Using a rodent model of adolescent intermittent ethanol (AIE) exposure in both sexes, we investigated the epigenetic mechanism mediated by enhancer of zeste 2 (EZH2), a histone methyltransferase, in regulating both the expression of activity-regulated cytoskeleton-associated protein (Arc) and an anxiety-like phenotype in adulthood. Here, we report that EZH2 protein levels were significantly higher in PKC-δ positive GABAergic neurons in the central nucleus of amygdala (CeA) of adult male and female rats after AIE. Reducing protein and mRNA levels of EZH2 using siRNA infusion in the CeA prevented AIE-induced anxiety-like behavior, increased H3K27me3, decreased H3K27ac at the Arc synaptic activity response element (SARE) site, and restored deficits in Arc mRNA and protein expression in both male and female adult rats. Our data indicate that an EZH2-mediated epigenetic mechanism in the CeA plays an important role in regulating anxiety-like behavior and Arc expression after AIE in both male and female rats in adulthood. This study suggests that EZH2 may serve as a tractable drug target for the treatment of adult psychopathology after adolescent alcohol exposure.


Subject(s)
Anxiety , Central Amygdaloid Nucleus , Enhancer of Zeste Homolog 2 Protein , Epigenesis, Genetic , Ethanol , Animals , Male , Female , Enhancer of Zeste Homolog 2 Protein/metabolism , Enhancer of Zeste Homolog 2 Protein/genetics , Central Amygdaloid Nucleus/metabolism , Central Amygdaloid Nucleus/drug effects , Rats , Anxiety/metabolism , Anxiety/genetics , Ethanol/pharmacology , Disease Models, Animal , Alcoholism/genetics , Alcoholism/metabolism , GABAergic Neurons/metabolism , GABAergic Neurons/drug effects , Rats, Sprague-Dawley , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism
9.
J Cell Sci ; 137(9)2024 May 01.
Article in English | MEDLINE | ID: mdl-38587458

ABSTRACT

Talin (herein referring collectively to talin 1 and 2) couples the actomyosin cytoskeleton to integrins and transmits tension to the extracellular matrix. Talin also interacts with numerous additional proteins capable of modulating the actin-integrin linkage and thus downstream mechanosignaling cascades. Here, we demonstrate that the scaffold protein Caskin2 interacts directly with the R8 domain of talin through its C-terminal LD motif. Caskin2 also associates with the WAVE regulatory complex to promote cell migration in an Abi1-dependent manner. Furthermore, we demonstrate that the Caskin2-Abi1 interaction is regulated by growth factor-induced phosphorylation of Caskin2 on serine 878. In MCF7 and UACC893 cells, which contain an amplification of CASKIN2, Caskin2 localizes in plasma membrane-associated plaques and around focal adhesions in cortical microtubule stabilization complexes. Taken together, our results identify Caskin2 as a novel talin-binding protein that might not only connect integrin-mediated adhesion to actin polymerization but could also play a role in crosstalk between integrins and microtubules.


Subject(s)
Adaptor Proteins, Signal Transducing , Cell Movement , Cytoskeletal Proteins , Protein Binding , Talin , Humans , Talin/metabolism , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/genetics , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Phosphorylation , MCF-7 Cells , Microtubules/metabolism , Focal Adhesions/metabolism , Integrins/metabolism
10.
Mol Biol Cell ; 35(6): ar85, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38656798

ABSTRACT

In response to pheromone Saccharomyces cerevisiae extend a mating projection. This process depends on the formation of polarized actin cables which direct secretion to the mating tip and translocate the nucleus for karyogamy. Here, we demonstrate that proper mating projection formation requires the formin Bni1, as well as the actin nucleation promoting activities of Bud6, but not the formin Bnr1. Further, Bni1 is required for pheromone gradient tracking. Our work also reveals unexpected new functions for Bil2 in the pheromone response. Previously we identified Bil2 as a direct inhibitor of Bnr1 during vegetative cell growth. Here, we show that Bil2 has Bnr1-independent functions in spatially focusing Bni1-GFP at mating projection tips, and in vitro Bil2 and its binding partner Bud6 organize Bni1 into clusters that nucleate actin assembly. bil2∆ cells also display entangled Bni1-generated actin cable arrays and defects in secretory vesicle transport and nuclear positioning. At low pheromone concentrations, bil2∆ cells are delayed in establishing a polarity axis, and at high concentrations they prematurely form a second and a third mating projection. Together, these results suggest that Bil2 promotes the proper formation and timing of mating projections by organizing Bni1 and maintaining a persistent axis of polarized growth.


Subject(s)
Actins , Pheromones , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae Proteins/genetics , Pheromones/metabolism , Actins/metabolism , Microfilament Proteins/metabolism , Microfilament Proteins/genetics , Cell Polarity/physiology , Cytoskeletal Proteins/metabolism
11.
Neurosci Lett ; 828: 137763, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38574849

ABSTRACT

The role of the hypothalamic cold-sensitive ion channels - transient receptor potential melastatin 8 (TRPM8) and transient receptor potential ankyrin 1 (TRPA1) in homeostatic systems of thermoregulation and water-salt balance - is not clear. The interaction of homeostatic systems of thermoregulation and water-salt balance without additional temperature load did not receive due attention, too. On the models of water-balance disturbance, we tried to elucidate some aspect of these problems. Body temperature (Tbody), O2 consumption, CO2 excretion, electrical muscle activity (EMA), temperature of tail skin (Ttail), plasma osmolality, as well as gene expression of hypothalamic TRPM8 and TRPA1 have been registered in rats of 3 groups: control; water-deprived (3 days under dry-eating); and hyperhydrated (6 days without dry food, drinking liquid 4 % sucrose). No relationship was observed between plasma osmolality and gene expression of Trpm8 and Trpa1. In water-deprived rats, the constriction of skin vessels, increased fat metabolism by 10 % and increased EMA by 48 % allowed the animals to maintain Tbody unchanged. The hyperhydrated rats did not develop sufficient mechanisms, and their Tbody decreased by 0.8 °C. The development of reactions was correlated with the expression of genes of thermosensitive ion channels in the anterior hypothalamus. Ttail had a direct correlation with the expression of the Trpm8 gene, whereas EMA directly correlated with the expression of the Trpa1 gene in water-deprived group. The obtained data attract attention from the point of view of management and correction of physiological functions by modulating the ion channel gene expression.


Subject(s)
Body Temperature Regulation , TRPA1 Cation Channel , TRPM Cation Channels , Animals , Rats , Body Temperature Regulation/genetics , Cold Temperature , Cytoskeletal Proteins/metabolism , Temperature , TRPA1 Cation Channel/metabolism , TRPM Cation Channels/metabolism
12.
PLoS One ; 19(4): e0300453, 2024.
Article in English | MEDLINE | ID: mdl-38683783

ABSTRACT

The activity-regulated cytoskeleton-associated protein (Arc) is a complex regulator of synaptic plasticity in glutamatergic neurons. Understanding its molecular function is key to elucidate the neurobiology of memory and learning, stress regulation, and multiple neurological and psychiatric diseases. The recent development of anti-Arc nanobodies has promoted the characterization of the molecular structure and function of Arc. This study aimed to validate two anti-Arc nanobodies, E5 and H11, as selective modulators of the human Arc N-lobe (Arc-NL), a domain that mediates several molecular functions of Arc through its peptide ligand binding site. The structural characteristics of recombinant Arc-NL-nanobody complexes were solved at atomic resolution using X-ray crystallography. Both anti-Arc nanobodies bind specifically to the multi-peptide binding site of Arc-NL. Isothermal titration calorimetry showed that the Arc-NL-nanobody interactions occur at nanomolar affinity, and that the nanobodies can displace a TARPγ2-derived peptide from the binding site. Thus, both anti-Arc-NL nanobodies could be used as competitive inhibitors of endogenous Arc ligands. Differences in the CDR3 loops between the two nanobodies indicate that the spectrum of short linear motifs recognized by the Arc-NL should be expanded. We provide a robust biochemical background to support the use of anti-Arc nanobodies in attempts to target Arc-dependent synaptic plasticity. Function-blocking anti-Arc nanobodies could eventually help unravel the complex neurobiology of synaptic plasticity and allow to develop diagnostic and treatment tools.


Subject(s)
Cytoskeletal Proteins , Nerve Tissue Proteins , Single-Domain Antibodies , Humans , Single-Domain Antibodies/chemistry , Single-Domain Antibodies/immunology , Single-Domain Antibodies/metabolism , Binding Sites , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/chemistry , Cytoskeletal Proteins/immunology , Ligands , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/immunology , Crystallography, X-Ray , Protein Binding , Models, Molecular , Amino Acid Sequence
13.
Mol Biol Cell ; 35(6): ar83, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38656792

ABSTRACT

The KMN (Knl1/Mis12/Ndc80) network at the kinetochore, primarily known for its role in chromosome segregation, has been shown to be repurposed during neurodevelopment. Here, we investigate the underlying neuronal mechanism and show that the KMN network promotes the proper axonal organization within the C. elegans head nervous system. Postmitotic degradation of KNL-1, which acts as a scaffold for signaling and has microtubule-binding activities at the kinetochore, led to disorganized ganglia and aberrant placement and organization of axons in the nerve ring - an interconnected axonal network. Through gene-replacement approaches, we demonstrate that the signaling motifs within KNL-1, responsible for recruiting protein phosphatase 1, and activating the spindle assembly checkpoint are required for neurodevelopment. Interestingly, while the microtubule-binding activity is crucial to KMN's neuronal function, microtubule dynamics and organization were unaffected in the absence of KNL-1. Instead, the NDC-80 microtubule-binding mutant displayed notable defects in axon bundling during nerve ring formation, indicating its role in facilitating axon-axon contacts. Overall, these findings provide evidence for a noncanonical role for the KMN network in shaping the structure and connectivity of the nervous system in C. elegans during brain development.


Subject(s)
Axons , Caenorhabditis elegans Proteins , Caenorhabditis elegans , Kinetochores , Microtubule-Associated Proteins , Microtubules , Neurons , Animals , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans Proteins/genetics , Axons/metabolism , Axons/physiology , Kinetochores/metabolism , Neurons/metabolism , Microtubule-Associated Proteins/metabolism , Microtubules/metabolism , Nervous System/metabolism , Spindle Apparatus/metabolism , Cytoskeletal Proteins/metabolism , Chromosome Segregation , Signal Transduction
14.
Cells ; 13(7)2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38607046

ABSTRACT

Membrane nanotubes (NTs) are dynamic communication channels connecting spatially separated cells even over long distances and promoting the transport of different cellular cargos. NTs are also involved in the intercellular spread of different pathogens and the deterioration of some neurological disorders. Transport processes via NTs may be controlled by cytoskeletal elements. NTs are frequently observed membrane projections in numerous mammalian cell lines, including various immune cells, but their functional significance in the 'antibody factory' B cells is poorly elucidated. Here, we report that as active channels, NTs of B-lymphoma cells can mediate bidirectional mitochondrial transport, promoted by the cooperation of two different cytoskeletal motor proteins, kinesin along microtubules and myosin VI along actin, and bidirectional transport processes are also supported by the heterogeneous arrangement of the main cytoskeletal filament systems of the NTs. We revealed that despite NTs and axons being different cell extensions, the mitochondrial transport they mediate may exhibit significant similarities. Furthermore, we found that microtubules may improve the stability and lifespan of B-lymphoma-cell NTs, while F-actin strengthens NTs by providing a structural framework for them. Our results may contribute to a better understanding of the regulation of the major cells of humoral immune response to infections.


Subject(s)
Cell Membrane Structures , Lymphoma , Nanotubes , Animals , Cytoskeleton/metabolism , Actins/metabolism , Nanotubes/chemistry , Mitochondria/metabolism , Cytoskeletal Proteins/metabolism , Lymphoma/metabolism , Mammals/metabolism
15.
Elife ; 132024 Apr 19.
Article in English | MEDLINE | ID: mdl-38639993

ABSTRACT

In the Firmicutes phylum, GpsB is a membrane associated protein that coordinates peptidoglycan synthesis with cell growth and division. Although GpsB has been studied in several bacteria, the structure, function, and interactome of Staphylococcus aureus GpsB is largely uncharacterized. To address this knowledge gap, we solved the crystal structure of the N-terminal domain of S. aureus GpsB, which adopts an atypical, asymmetric dimer, and demonstrates major conformational flexibility that can be mapped to a hinge region formed by a three-residue insertion exclusive to Staphylococci. When this three-residue insertion is excised, its thermal stability increases, and the mutant no longer produces a previously reported lethal phenotype when overexpressed in Bacillus subtilis. In S. aureus, we show that these hinge mutants are less functional and speculate that the conformational flexibility imparted by the hinge region may serve as a dynamic switch to fine-tune the function of the GpsB complex and/or to promote interaction with its various partners. Furthermore, we provide the first biochemical, biophysical, and crystallographic evidence that the N-terminal domain of GpsB binds not only PBP4, but also FtsZ, through a conserved recognition motif located on their C-termini, thus coupling peptidoglycan synthesis to cell division. Taken together, the unique structure of S. aureus GpsB and its direct interaction with FtsZ/PBP4 provide deeper insight into the central role of GpsB in S. aureus cell division.


Subject(s)
Bacterial Proteins , Cytoskeletal Proteins , Protein Binding , Protein Conformation , Staphylococcus aureus , Staphylococcus aureus/metabolism , Staphylococcus aureus/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/chemistry , Crystallography, X-Ray , Penicillin-Binding Proteins/metabolism , Penicillin-Binding Proteins/genetics , Penicillin-Binding Proteins/chemistry , Models, Molecular
16.
PLoS One ; 19(4): e0302251, 2024.
Article in English | MEDLINE | ID: mdl-38635746

ABSTRACT

Sterile alpha and TIR motif-containing 1 (SARM1) is a protein involved in programmed death of injured axons. Following axon injury or a drug-induced insult, the TIR domain of SARM1 degrades the essential molecule nicotinamide adenine dinucleotide (NAD+), leading to a form of axonal death called Wallerian degeneration. Degradation of NAD+ by SARM1 is essential for the Wallerian degeneration process, but accumulating evidence suggest that other activities of SARM1, beyond the mere degradation of NAD+, may be necessary for programmed axonal death. In this study we show that the TIR domains of both human and fruit fly SARM1 produce 1''-2' and 1''-3' glycocyclic ADP-ribose (gcADPR) molecules as minor products. As previously reported, we observed that SARM1 TIR domains mostly convert NAD+ to ADPR (for human SARM1) or cADPR (in the case of SARM1 from Drosophila melanogaster). However, we now show that human and Drosophila SARM1 additionally convert ~0.1-0.5% of NAD+ into gcADPR molecules. We find that SARM1 TIR domains produce gcADPR molecules both when purified in vitro and when expressed in bacterial cells. Given that gcADPR is a second messenger involved in programmed cell death in bacteria and likely in plants, we propose that gcADPR may play a role in SARM1-induced programmed axonal death in animals.


Subject(s)
NAD , Wallerian Degeneration , Animals , Humans , Wallerian Degeneration/metabolism , Wallerian Degeneration/pathology , NAD/metabolism , Drosophila melanogaster/metabolism , Axons/metabolism , Bacteria/metabolism , Adenosine Diphosphate Ribose/metabolism , Armadillo Domain Proteins/genetics , Armadillo Domain Proteins/metabolism , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism
17.
BMC Cancer ; 24(1): 443, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38600440

ABSTRACT

BACKGROUND: Altered glycosylation is a hallmark of cancer associated with therapy resistance and tumor behavior. In this study, we investigated the glycosylation profile of stemness-related proteins OCT4, CIP2A, MET, and LIMA1 in HNSCC tumors. METHODS: Tumor, adjacent normal tissue, and blood samples of 25 patients were collected together with clinical details. After tissue processing, lectin-based glycovariant screens were performed. RESULTS: Strong correlation between glycosylation profiles of all four stemness-related proteins was observed in tumor tissue, whereas glycosylation in tumor tissue, adjacent normal tissue, and serum was differential. CONCLUSIONS: A mannose- and galactose-rich glycosylation niche associated with stemness-related proteins was identified.


Subject(s)
Carcinoma, Squamous Cell , Head and Neck Neoplasms , Humans , Squamous Cell Carcinoma of Head and Neck , Carcinoma, Squamous Cell/pathology , Glycosylation , Cell Line, Tumor , Cytoskeletal Proteins/metabolism
18.
Elife ; 132024 Apr 04.
Article in English | MEDLINE | ID: mdl-38573307

ABSTRACT

The perinuclear theca (PT) is a dense cytoplasmic web encapsulating the sperm nucleus. The physiological roles of PT in sperm biology and the clinical relevance of variants of PT proteins to male infertility are still largely unknown. We reveal that cylicin-1, a major constituent of the PT, is vital for male fertility in both mice and humans. Loss of cylicin-1 in mice leads to a high incidence of malformed sperm heads with acrosome detachment from the nucleus. Cylicin-1 interacts with itself, several other PT proteins, the inner acrosomal membrane (IAM) protein SPACA1, and the nuclear envelope (NE) protein FAM209 to form an 'IAM-cylicins-NE' sandwich structure, anchoring the acrosome to the nucleus. WES (whole exome sequencing) of more than 500 Chinese infertile men with sperm head deformities was performed and a CYLC1 variant was identified in 19 patients. Cylc1-mutant mice carrying this variant also exhibited sperm acrosome/head deformities and reduced fertility, indicating that this CYLC1 variant most likely affects human male reproduction. Furthermore, the outcomes of assisted reproduction were reported for patients harbouring the CYLC1 variant. Our findings demonstrate a critical role of cylicin-1 in the sperm acrosome-nucleus connection and suggest CYLC1 variants as potential risk factors for human male fertility.


Subject(s)
Acrosome , Infertility, Male , Animals , Humans , Male , Mice , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism , Infertility, Male/genetics , Membrane Proteins/genetics , Semen , Sperm Head , Spermatozoa
19.
Sci Rep ; 14(1): 6379, 2024 03 16.
Article in English | MEDLINE | ID: mdl-38493244

ABSTRACT

The regulatory mechanism of long non-coding RNAs (lncRNAs) in autophagy is as yet not well established. In this research, we show that the long non-coding RNA MLLT4 antisense RNA 1 (lncRNA MLLT4-AS1) is induced by the MTORC inhibitor PP242 and rapamycin in cervical cells. Overexpression of MLLT4-AS1 promotes autophagy and inhibits tumorigenesis and the migration of cervical cancer cells, whereas knockdown of MLLT4-AS1 attenuates PP242-induced autophagy. Mass spectrometry, RNA fluorescence in situ hybridization (RNA-FISH), and immunoprecipitation assays were performed to identify the direct interactions between MLLT4-AS1 and other associated targets, such as myosin-9 and autophagy-related 14(ATG14). MLLT4-AS1 was upregulated by H3K27ac modification with PP242 treatment, and knockdown of MLLT4-AS1 reversed autophagy by modulating ATG14 expression. Mechanically, MLLT4-AS1 was associated with the myosin-9 protein, which further promoted the transcription activity of the ATG14 gene. In conclusion, we demonstrated that MLLT4-AS1 acts as a potential tumor suppressor in cervical cancer by inducing autophagy, and H3K27ac modification-induced upregulation of MLLT4-AS1 could cause autophagy by associating with myosin-9 and promoting ATG14 transcription.


Subject(s)
Adaptor Proteins, Vesicular Transport , MicroRNAs , RNA, Long Noncoding , Uterine Cervical Neoplasms , Female , Humans , RNA, Antisense/genetics , RNA, Antisense/metabolism , RNA, Long Noncoding/metabolism , Uterine Cervical Neoplasms/genetics , In Situ Hybridization, Fluorescence , Cell Line, Tumor , Cell Proliferation/genetics , Carcinogenesis/genetics , Cell Transformation, Neoplastic/genetics , Cytoskeletal Proteins/metabolism , Myosins/genetics , Myosins/metabolism , Autophagy/genetics , MicroRNAs/genetics , Gene Expression Regulation, Neoplastic , Autophagy-Related Proteins/genetics
20.
Biochem Biophys Res Commun ; 705: 149738, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38447391

ABSTRACT

The proliferation and apoptosis of ovarian granulosa cells are important for folliculogenesis. As a transcription factor, SRY-box transcription factor 4 (SOX4) has important roles in regulating cellular proliferation and apoptosis. Nonetheless, the regulatory mechanisms of SOX4 on proliferation and apoptosis of granulosa cells remain elusive. Therefore, a stably overexpressed SOX4 ovarian granulosa cell line KGN was generated by lentivirus encapsulation. We observed that overexpression of SOX4 inhibits apoptosis, promotes proliferation and migration of KGN cells. Comparative analysis of the transcriptome revealed 868 upregulated and 696 downregulated DEGs in LV-SOX4 in comparison with LV-CON KGN cell lines. Afterward, further assessments were performed to explore the possible functions about these DEGs. The data showed their involvement in many biological processes, particularly the Hippo signaling pathway. Moreover, the expression levels of YAP1, WWTR1, WTIP, DLG3, CCN2, and AMOT, which were associated with the Hippo signaling pathway, were further validated by qRT-PCR. In addition, the protein expression levels of YAP1 were markedly elevated, while p-YAP1 were notably reduced after overexpression of SOX4 in KGN cells. Thus, these results suggested that SOX4 regulates apoptosis, proliferation and migration of KGN cells, at least partly, through activation of the Hippo signaling pathway, which might be implicated in mammalian follicle development.


Subject(s)
Granulosa Cells , Hippo Signaling Pathway , Female , Animals , Humans , Cell Line, Tumor , Granulosa Cells/metabolism , Cell Proliferation , Apoptosis , Mammals/metabolism , SOXC Transcription Factors/genetics , SOXC Transcription Factors/metabolism , Cytoskeletal Proteins/metabolism , Co-Repressor Proteins/metabolism
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