Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 15 de 15
Filter
Add more filters










Publication year range
1.
Microbiol Spectr ; 10(6): e0228422, 2022 12 21.
Article in English | MEDLINE | ID: mdl-36314912

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) is a group of pathogenic bacteria that are infamously resistant to ß-lactam antibiotics, a property attributed to the mecA gene. Recent studies have reported that mutations associated with the promoter region of pbp4 demonstrated high levels of ß-lactam resistance, suggesting the role of PBP4 as an important non-mecA mediator of ß-lactam resistance. The pbp4-promoter-associated mutations have been detected in strains with or without mecA. Our previous studies that were carried out in strains devoid of mecA described that pbp4-promoter-associated mutations lead to PBP4 overexpression and ß-lactam resistance. In this study, by introducing various pbp4-promoter-associated mutations in the genome of a MRSA strain, we demonstrate that PBP4 overexpression can supplement mecA-associated resistance in S. aureus and can lead to increased ß-lactam resistance. The promoter and regulatory region of pbp4 is shared with a divergently transcribed gene, abcA, which encodes a multidrug exporter. We demonstrate that the promoter mutations caused an upregulation of pbp4 and downregulation of abcA, confirming that the resistant phenotype is associated with PBP4 overexpression. PBP4 has also been associated with staphylococcal pathogenesis, however, its exact role remains unclear. Using a Caenorhabditis elegans model, we demonstrate that strains having increased PBP4 expression are less virulent than wild-type strains, suggesting that ß-lactam resistance mediated via PBP4 likely comes at the cost of virulence. IMPORTANCE Our study demonstrates the ability of PBP4 to be an important mediator of ß-lactam resistance in not only methicillin-susceptible Staphylococcus aureus (MSSA) background strains as previously demonstrated but also in MRSA strains. When present together, PBP2a and PBP4 overexpression can produce increased levels of ß-lactam resistance, causing complications in treatment. Thus, this study suggests the importance of monitoring PBP4-associated resistance in clinical settings, as well as understanding the mechanistic basis of associated resistance, so that treatments targeting PBP4 may be developed. This study also demonstrates that S. aureus strains with increased PBP4 expression are less pathogenic, providing important hints about the role of PBP4 in S. aureus resistance and pathogenesis.


Subject(s)
Methicillin-Resistant Staphylococcus aureus , Staphylococcus aureus , Penicillin-Binding Proteins/metabolism , Virulence/genetics , beta-Lactam Resistance/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Microbial Sensitivity Tests
2.
Proc Natl Acad Sci U S A ; 118(16)2021 04 20.
Article in English | MEDLINE | ID: mdl-33859044

ABSTRACT

Age-related macular degeneration (AMD) is a leading cause of blindness among the elderly. Canonical disease models suggest that defective interactions between complement factor H (CFH) and cell surface heparan sulfate (HS) result in increased alternative complement pathway activity, cytolytic damage, and tissue inflammation in the retina. Although these factors are thought to contribute to increased disease risk, multiple studies indicate that noncanonical mechanisms that result from defective CFH and HS interaction may contribute to the progression of AMD as well. A total of 60 ciliated sensory neurons in the nematode Caenorhabditis elegans detect chemical, olfactory, mechanical, and thermal cues in the environment. Here, we find that a C. elegans CFH homolog localizes on CEP mechanosensory neuron cilia where it has noncanonical roles in maintaining inversin/NPHP-2 within its namesake proximal compartment and preventing inversin/NPHP-2 accumulation in distal cilia compartments in aging adults. CFH localization and maintenance of inversin/NPHP-2 compartment integrity depend on the HS 3-O sulfotransferase HST-3.1 and the transmembrane proteoglycan syndecan/SDN-1. Defective inversin/NPHP-2 localization in mouse and human photoreceptors with CFH mutations indicates that these functions and interactions may be conserved in vertebrate sensory neurons, suggesting that previously unappreciated defects in cilia structure may contribute to the progressive photoreceptor dysfunction associated with CFH loss-of-function mutations in some AMD patients.


Subject(s)
Complement Factor H/metabolism , Heparitin Sulfate/metabolism , Retina/metabolism , Animals , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/metabolism , Cilia/metabolism , Complement Factor H/physiology , Heparitin Sulfate/physiology , Macular Degeneration/metabolism , Macular Degeneration/physiopathology , Neurons/metabolism , Transcription Factors/metabolism
3.
PLoS One ; 14(8): e0220849, 2019.
Article in English | MEDLINE | ID: mdl-31393918

ABSTRACT

Mutations in ATP13A2 cause Kufor-Rakeb syndrome (KRS), a juvenile form of Parkinson's disease (PD) with dementia. However, the mechanisms by which mutations in ATP13A2 cause KRS is not understood. The mutations lead to misfolding of the translated Atp13a2 protein and its premature degradation in the endoplasmic reticulum, never reaching the lysosome where the protein is thought to function. Atp13a2 is a P-type ATPase, a class of proteins that function in ion transport. Indeed, studies of human, mouse, and yeast Atp13a2 proteins suggest a possible involvement in regulation of heavy metal toxicity. Here we report on the cytoprotective function of Atp13a2 on HeLa cells and dopamine neurons of Caenorhabditis elegans (C. elegans). HeLa cells stably overexpressing V5- tagged Atp13a2Isoform-1 protein were more resistant to elevated manganese exposure and to starvation-induced cell death compared to cells not overexpressing the protein. Because PD is characterized by loss of dopamine neurons, we generated transgenic C. elegans expressing GFP-tagged human Atp13a2 protein in dopamine neurons. The transgenic animals exhibited higher resistance to dopamine neuron degeneration after acute exposure to manganese compared to nematodes that expressed GFP alone. The results suggest Atp13a2 Isoform-1 protein confers cytoprotection against toxic insults, including those that cause PD syndromes.


Subject(s)
Cell Death , Manganese/toxicity , Proton-Translocating ATPases/pharmacology , Starvation , Animals , Animals, Genetically Modified , Caenorhabditis elegans/cytology , Caenorhabditis elegans/genetics , Dopaminergic Neurons/drug effects , HeLa Cells , Humans , Parkinson Disease/prevention & control , Protective Agents/metabolism , Protein Isoforms , Proton-Translocating ATPases/genetics , Proton-Translocating ATPases/metabolism
4.
Elife ; 62017 05 02.
Article in English | MEDLINE | ID: mdl-28463106

ABSTRACT

Over 170 different mutations in the gene encoding SOD1 all cause amyotrophic lateral sclerosis (ALS). Available studies have been primarily focused on the mechanisms underlying mutant SOD1 cytotoxicity. How cells defend against the cytotoxicity remains largely unknown. Here, we show that misfolding of ALS-linked SOD1 mutants and wild-type (wt) SOD1 exposes a normally buried nuclear export signal (NES)-like sequence. The nuclear export carrier protein CRM1 recognizes this NES-like sequence and exports misfolded SOD1 to the cytoplasm. Antibodies against the NES-like sequence recognize misfolded SOD1, but not native wt SOD1 both in vitro and in vivo. Disruption of the NES consensus sequence relocalizes mutant SOD1 to the nucleus, resulting in higher toxicity in cells, and severer impairments in locomotion, egg-laying, and survival in Caenorhabditis elegans. Our data suggest that SOD1 mutants are removed from the nucleus by CRM1 as a defense mechanism against proteotoxicity of misfolded SOD1 in the nucleus.


Subject(s)
Active Transport, Cell Nucleus , Karyopherins/metabolism , Protein Folding , Receptors, Cytoplasmic and Nuclear/metabolism , Superoxide Dismutase-1/metabolism , Superoxide Dismutase-1/toxicity , Amino Acid Motifs , Animals , Caenorhabditis elegans , Mutant Proteins/genetics , Mutant Proteins/metabolism , Mutant Proteins/toxicity , Protein Binding , Protein Sorting Signals , Superoxide Dismutase-1/chemistry , Exportin 1 Protein
5.
Exp Cell Res ; 318(20): 2543-7, 2012 Dec 10.
Article in English | MEDLINE | ID: mdl-22981695

ABSTRACT

Fibulins are evolutionarily conserved extracellular matrix (ECM) proteins that assemble in elastic fibers and basement membranes. Caenorhabditis elegans has a single fibulin gene that produces orthologs of vertebrate fibulin-1 C and D splice forms. In a structure-function analysis of fibulin-1 domains, a series of deletion constructs show that EGF repeats 4 and 5 are required for the hemicentin-dependent assembly and function of fibulin-1D in native locations. In contrast, constructs missing the second EGF repeat of fibulin-1D (EGF2D) assemble in ectopic locations in a hemicentin dependent manner. Constructs that contain EGF2D are cleaved into two fragments, but constructs with EGF2D missing are not, suggesting that a protease binds and/or cleaves fibulin-1D at a site that is likely within EGF2D. Together, the data suggests that EGF repeats 4 and 5 promote interaction with hemicentin while a region within EGF2D suppresses ectopic interactions with hemicentin and this suppression may be protease dependent.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/genetics , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , Membrane Proteins/metabolism , Protein Interaction Domains and Motifs/genetics , Alternative Splicing/genetics , Amino Acid Sequence , Animals , Animals, Genetically Modified , Caenorhabditis elegans Proteins/genetics , Calcium-Binding Proteins/chemistry , Extracellular Matrix Proteins/chemistry , Extracellular Matrix Proteins/genetics , Extracellular Matrix Proteins/metabolism , Membrane Proteins/genetics , Molecular Sequence Data , Tandem Repeat Sequences/genetics
6.
Commun Integr Biol ; 4(4): 433-5, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21966563

ABSTRACT

Interactions between extracellular matrix (ECM) proteins and transmembrane receptors mediate changes in cell shape during cell migration, adhesion, differentiation and polarization. Cytokinesis is the final step in cell division as cells employ a contractile ring composed of actin and myosin to partition one cell into two. During the partition process, an invagination in nascent membrane forms a new extracellular space called the cleavage furrow. Despite the dramatic changes in cell shape during cytokinesis, existing models include no role for the ECM. In a recent paper, we show that hemicentins assemble in the cleavage furrow of C. elegans germ cells and mouse embryo blastomeres. Hemicentin depletion results in membrane destabilization, cleavage furrow retraction and cytokinesis failure. The data suggest that hemicentins and other ECM proteins stabilize the cleavage furrow during cytokinesis of multiple cell types.

7.
Cell Cycle ; 10(12): 1916-20, 2011 Jun 15.
Article in English | MEDLINE | ID: mdl-21558805

ABSTRACT

Interactions between extracellular matrix (ECM) proteins and their transmembrane receptors mediate cytoskeletal reorganization and corresponding changes in cell shape during cell migration, adhesion, differentiation and polarization. Cytokinesis is the final step in cell division as cells employ a contractile ring composed of actin and myosin to partition one cell into two. Cells undergo dramatic changes in cell shape during the division process, creating new membrane and forming an extracellular invagination called the cleavage furrow. However, existing models of cytokinesis include no role for the ECM. In a recent paper, we demonstrate that depletion of a large secreted protein, hemicentin, results in membrane destabilization, cleavage furrow retraction and cytokinesis failure in C. elegans germ cells and in pre-implantation mouse embryos. Here, we demonstrate that cytokinesis failure produces tetraploid intermediate cells with multipolar spindles, providing a potential explanation for the large number of aneuploid progeny observed among C. elegans hemicentin mutant hermaphrodites.


Subject(s)
Aneuploidy , Caenorhabditis elegans/cytology , Cytokinesis , Extracellular Matrix Proteins/physiology , Germ Cells/cytology , Animals , Germ-Line Mutation , Mice , Tetraploidy
8.
Curr Biol ; 21(2): 114-9, 2011 Jan 25.
Article in English | MEDLINE | ID: mdl-21215633

ABSTRACT

Developmental modifications in cell shape depend on dynamic interactions between the extracellular matrix and cytoskeleton. In contrast, existing models of cytokinesis describe substantial cell surface remodeling that involves many intracellular regulatory and structural proteins but includes no contribution from the extracellular matrix [1-3]. Here, we show that extracellular hemicentins assemble at the cleavage furrow of dividing cells in the C. elegans germline and in preimplantation mouse embryos. In the absence of hemicentin, cleavage furrows form but retract prior to completion, resulting in multinucleate cells. In addition to their role in tissue organization, the data indicate that hemicentins are the first secreted proteins required during mammalian development and the only known secreted proteins required for cytokinesis, with an evolutionarily conserved role in stabilizing and preventing retraction of nascent cleavage furrows. Together with studies showing that extracellular polysaccharides are required for cytokinesis in diverse species [4-9], our data suggest that assembly of a cell type-specific extracellular matrix may be a general requirement for cleavage furrow maturation and contractile ring function during cytokinesis.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Cytokinesis/physiology , Extracellular Matrix Proteins/metabolism , Gene Expression Regulation, Developmental/physiology , Membrane Proteins/metabolism , Animals , Blastocyst , Caenorhabditis elegans , Caenorhabditis elegans Proteins/genetics , Cell Membrane , Extracellular Matrix Proteins/genetics , Female , Heterozygote , Male , Membrane Proteins/genetics , Mice , Mitosis/physiology , Parthenogenesis , Protein Transport
9.
J Histochem Cytochem ; 55(2): 119-26, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17015624

ABSTRACT

Hemicentins are recently described extracellular matrix (ECM) proteins with a single ortholog in C. elegans that assembles into discrete tracks constricting broad regions of epithelial cell contact into adhesive and flexible line-shaped junctions. There are two highly conserved hemicentin genes in most vertebrate species; however, nothing is known about the function or distribution of vertebrate hemicentins. To determine the distribution of vertebrate hemicentins, we used a polyclonal antibody to stain mouse tissue and showed that hemicentins are found in the pericellular ECM of epithelial cells in a number of tissues including embryonic trophectoderm and adult skin and tongue, in addition to the ECM of some, but not all, blood vessels. Hemicentins also assemble on multiple epithelia in the eye, including cornea, lens, and retina. The pericellular localization of vertebrate hemicentins on epithelia and other cell surfaces suggests that vertebrate hemicentins, like their nematode counterpart, are secreted ECM proteins likely to have a role in the architecture of adhesive and flexible cell junctions, particularly in tissues subject to significant amounts of mechanical stress.


Subject(s)
Epithelial Cells/metabolism , Extracellular Matrix Proteins/metabolism , Amino Acid Sequence , Animals , Antibodies , Blood Vessels/metabolism , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/immunology , Conserved Sequence , Epithelium/metabolism , Extracellular Matrix Proteins/genetics , Extracellular Matrix Proteins/immunology , Eye/metabolism , Membrane Proteins/genetics , Membrane Proteins/immunology , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Organ Specificity , Reverse Transcriptase Polymerase Chain Reaction , Skin/metabolism , Tongue/metabolism
10.
Cell Res ; 16(11): 872-8, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17031392

ABSTRACT

Hemicentins are conserved extracellular matrix proteins discovered in Caenorhabditis elegans, with orthologs in all vertebrate species including human and mouse. Hemicentins share a single, highly conserved amino-terminal von Willebrand A domain, followed by a long (>40) stretch of immunoglobulin repeats, multiple tandem epidermal growth factors and a fibulin-like carboxy-terminal module. C. elegans has a single hemicentin gene that has pleiotropic functions in transient cell contacts that are required for cell migration and basement membrane invasion and in stable contacts at hemidesmosome-mediated cell junctions and elastic fiber-like structures. Here, we summarize what is known about the function of hemicentin in C. elegans and discuss implications for hemicentin function in other species.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , Animals , Caenorhabditis elegans/cytology , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/physiology , Calcium-Binding Proteins/metabolism , Cell Adhesion/physiology , Extracellular Matrix Proteins/genetics , Extracellular Matrix Proteins/metabolism , Extracellular Matrix Proteins/physiology , Mutation/genetics
11.
Dev Dyn ; 235(10): 2632-40, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16804890

ABSTRACT

Fibulin-1C and fibulin-1D splice variants have been conserved throughout metazoan evolution and have distinct functions in Caenorhabditis elegans development. Both splice variants are required for the assembly of hemidesmosome-mediated mechanosensory neuron and uterine attachments, although the molecular associations that underlie their distinct functions at these locations are not known. Here, we show that the assembly of fibulin-1C and fibulin-1D splice variants at these anchorages is dependent upon distinct components of the extracellular matrix (ECM): Fibulin-1D assembly at uterine and mechanosensory neurons attachments is dependent upon a perlecan/ UNC-52 splice variant that includes alternately spliced IG8-IG10, whereas the assembly of fibulin-1C at mechanosensory neuron attachments is dependent upon laminin/ EPI-1. These data not only indicate that fibulin-1C and fibulin-1D are components of distinct networks of ECM but also demonstrates a novel function for a major class of perlecan splice variants found in C. elegans and mouse. In addition, we demonstrate that overexpression of another ECM protein, collagen XVIII, can suppress gonad morphogenesis defects associated with loss of fibulin-1C, suggesting that some genetic defects that result in a weakened basement membrane can be compensated by overexpression of genes for ECM components that stabilize basement membranes.


Subject(s)
Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans/genetics , Calcium-Binding Proteins/genetics , Extracellular Matrix/metabolism , Heparan Sulfate Proteoglycans/genetics , Membrane Proteins/genetics , Proteoglycans/genetics , Alternative Splicing , Amino Acid Sequence , Animals , Basement Membrane/metabolism , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/metabolism , Calcium-Binding Proteins/metabolism , Collagen Type XVIII/genetics , Collagen Type XVIII/metabolism , Extracellular Matrix/physiology , Gonads/metabolism , Gonads/pathology , Heparan Sulfate Proteoglycans/metabolism , Laminin/genetics , Laminin/metabolism , Membrane Proteins/metabolism , Mice , Microscopy, Interference/methods , Models, Biological , Molecular Sequence Data , Neurons/metabolism , Neurons/pathology , Protein Binding , Protein Isoforms/genetics , Protein Isoforms/metabolism , Proteoglycans/metabolism , RNA Interference , Signal Transduction/physiology
12.
J Biol Chem ; 281(33): 23606-10, 2006 Aug 18.
Article in English | MEDLINE | ID: mdl-16798744

ABSTRACT

Hemicentins are conserved extracellular matrix proteins characterized by a single von Willebrand A (VWA) domain at the amino terminus, a long stretch (>40) of tandem immunoglobulin domains, multiple tandem epidermal growth factors (EGFs), and a single fibulin-like carboxyl-terminal module. In Caenorhabditis elegans, hemicentin is secreted from muscle and gonadal leader cells and assembles at multiple locations into discrete tracks that constrict broad regions of cell contact into adhesive and flexible line-shaped junctions. To determine hemicentin domains critical for function and assembly, we have expressed fragments of hemicentin as GFP tagged fusion proteins in C. elegans. We find that a hemicentin fragment containing the VWA domain can target to multiple assembly sites when expressed under the control of either endogenous hemicentin regulatory sequences or the muscle-specific unc-54 promoter. A hemicentin fragment containing the EGF and fibulin-like carboxyl-terminal modules can co-assemble with existing hemicentin polymers in wild-type animals but has no detectable function in the absence of endogenous hemicentin. The data suggest that the VWA domain is a cell binding domain whose function is to target hemicentin to sites of assembly and the EGF/fibulin-like carboxyl-terminal modules constitute an assembly domain that mediates direct interactions between hemicentin monomers during the hemicentin assembly process.


Subject(s)
Caenorhabditis elegans Proteins/chemistry , Caenorhabditis elegans Proteins/metabolism , Extracellular Matrix/metabolism , Membrane Proteins/chemistry , Membrane Proteins/metabolism , Protein Processing, Post-Translational , Animals , Caenorhabditis elegans Proteins/genetics , Cell Adhesion/physiology , Cell Division/physiology , Extracellular Matrix/chemistry , Extracellular Matrix/genetics , Green Fluorescent Proteins/metabolism , Male , Membrane Proteins/genetics , Muscles/physiology , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Fragments/metabolism , Protein Processing, Post-Translational/genetics , Protein Structure, Tertiary , von Willebrand Factor/chemistry
13.
Hum Mol Genet ; 15(6): 1025-41, 2006 Mar 15.
Article in English | MEDLINE | ID: mdl-16461334

ABSTRACT

Expanded polyglutamine (polyQ) tracts are associated with the induction of protein aggregation and cause cytotoxicity in nine different neurodegenerative disorders. Here, we report that ubiquilin suppresses polyQ-induced protein aggregation and toxicity in cells and in an animal model of Huntington's disease. Overexpression of ubiquilin in HeLa cells and primary neurons reduced aggregation of polyQ-containing proteins and cell death induced by overexpression of a green fluorescent protein (GFP)-huntingtin fusion protein containing 74 polyQ repeats [GFP-Htt(Q74)], in a dose-dependent manner. Moreover, overexpression of ubiquilin suppressed oxidative stress-induced cell death in HeLa cell lines stably expressing GFP-Htt(Q74). In contrast, knockdown of ubiquilin expression in these cell lines was associated with increases in DNA fragmentation, caspase activation, GFP-fusion protein aggregation, and cell death. Caenorhabditis elegans lines expressing GFP-Htt fusion proteins in body wall muscle displayed a polyQ repeat length-dependent decrease in body movement compared with wild-type animals. RNA interference of the C. elegans ubiquilin gene exacerbated the motility defect, whereas overexpression of ubiquilin prevented, and could rescue, loss of worm movement induced by overexpression of GFP-Htt(Q55). These results suggest that ubiquilin might be a novel therapeutic target for treating polyQ diseases.


Subject(s)
Carrier Proteins/physiology , Cell Cycle Proteins/physiology , Huntington Disease/metabolism , Neurons/metabolism , Peptides/antagonists & inhibitors , Peptides/toxicity , Adaptor Proteins, Signal Transducing , Animals , Animals, Genetically Modified , Autophagy-Related Proteins , Behavior, Animal/physiology , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Carrier Proteins/biosynthesis , Carrier Proteins/genetics , Cell Cycle Proteins/biosynthesis , Cell Cycle Proteins/genetics , Cell Line , Cells, Cultured , Disease Models, Animal , HeLa Cells , Humans , Huntingtin Protein , Mice , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/genetics , Nuclear Proteins/biosynthesis , Nuclear Proteins/genetics , RNA Interference , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism
14.
Development ; 132(19): 4223-34, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16120639

ABSTRACT

Fibulins are a family of extracellular glycoproteins associated with basement membranes and elastic fibers in vertebrates. Conservation of the fibulin-1 gene throughout metazoan evolution includes fibulin-1C and fibulin-1D alternate splice variants, although little is known about variant specific functions that would justify this striking structural conservation. We have therefore investigated the structure, localization and loss-of-function phenotype specific to both fibulin-1 variants in C. elegans. We find that fibulin-1C has specific roles during pharynx, intestine, gonad and muscle morphogenesis, being required to regulate cell shape and adhesion, whereas fibulin-1D assembles in flexible polymers that connect the pharynx and body-wall-muscle basement membranes. The assembly of fibulin-1C and fibulin-1D in multiple locations is dependent upon the presence of hemicentin, a recently described extracellular member of the immunoglobulin superfamily. We suggest that the distinct developmental roles and hemicentin-dependent assembly for fibulin-1 splice variants demonstrated here may be relevant to fibulin-1 and possibly other fibulin family members in non-nematode species.


Subject(s)
Caenorhabditis elegans Proteins/physiology , Caenorhabditis elegans/metabolism , Calcium-Binding Proteins/physiology , Membrane Proteins/physiology , Abdominal Muscles/growth & development , Abdominal Muscles/metabolism , Abdominal Muscles/ultrastructure , Alternative Splicing , Animals , Basement Membrane/metabolism , Caenorhabditis elegans/genetics , Caenorhabditis elegans/growth & development , Caenorhabditis elegans Proteins/genetics , Calcium-Binding Proteins/genetics , Cell Adhesion/physiology , Cell Shape/physiology , Gonads/growth & development , Gonads/metabolism , Gonads/ultrastructure , Intestinal Mucosa/metabolism , Intestines/growth & development , Intestines/ultrastructure , Membrane Proteins/genetics , Microscopy, Electron, Transmission , Morphogenesis , Mutation , Pharynx/growth & development , Pharynx/metabolism , Pharynx/ultrastructure
15.
Development ; 130(14): 3343-58, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12783803

ABSTRACT

Laminins are heterotrimeric (alpha/beta/gamma) glycoproteins that form a major polymer within basement membranes. Different alpha, beta and gamma subunits can assemble into various laminin isoforms that have different, but often overlapping, distributions and functions. In this study, we examine the contributions of the laminin alpha subunits to the development of C. elegans. There are two alpha, one beta and one gamma laminin subunit, suggesting two laminin isoforms that differ by their alpha subunit assemble in C. elegans. We find that near the end of gastrulation and before other basement membrane components are detected, the alpha subunits are secreted between primary tissue layers and become distributed in different patterns to the surfaces of cells. Mutations in either alpha subunit gene cause missing or disrupted extracellular matrix where the protein normally localizes. Cell-cell adhesions are abnormal: in some cases essential cell-cell adhesions are lacking, while in other cases, cells inappropriately adhere to and invade neighboring tissues. Using electron microscopy, we observe adhesion complexes at improper cell surfaces and disoriented cytoskeletal filaments. Cells throughout the animal show defective differentiation, proliferation or migration, suggesting a general disruption of cell-cell signaling. The results suggest a receptor-mediated process localizes each secreted laminin to exposed cell surfaces and that laminin is crucial for organizing extracellular matrix, receptor and intracellular proteins at those surfaces. We propose this supramolecular architecture regulates adhesions and signaling between adjacent tissues.


Subject(s)
Caenorhabditis elegans/embryology , Laminin/chemistry , Laminin/physiology , Animals , Basement Membrane/metabolism , Cell Adhesion , Cell Differentiation , Cell Division , Cell Movement , DNA, Complementary/metabolism , Extracellular Matrix/metabolism , Homozygote , Microscopy, Electron , Microscopy, Fluorescence , Models, Genetic , Mutation , Protein Isoforms , Protein Structure, Tertiary , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction
SELECTION OF CITATIONS
SEARCH DETAIL
...