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1.
Sci Rep ; 8(1): 3178, 2018 02 16.
Article in English | MEDLINE | ID: mdl-29453334

ABSTRACT

Wnt signaling is an evolutionarily conserved signaling route required for development and homeostasis. While canonical, ß-catenin-dependent Wnt signaling is well studied and has been linked to many forms of cancer, much less is known about the role of non-canonical, ß-catenin-independent Wnt signaling. Here, we aimed at identifying a ß-catenin-independent Wnt target gene signature in order to understand the functional significance of non-canonical signaling in colon cancer cells. Gene expression profiling was performed after silencing of key components of Wnt signaling pathway and an iterative signature algorithm was applied to predict pathway-dependent gene signatures. Independent experiments confirmed several target genes, including PLOD2, HADH, LCOR and REEP1 as non-canonical target genes in various colon cancer cells. Moreover, non-canonical Wnt target genes are regulated via RoR2, Dvl2, ATF2 and ATF4. Furthermore, we show that the ligands Wnt5a/b are upstream regulators of the non-canonical signature and moreover regulate proliferation of cancer cells in a ß-catenin-independent manner. Our experiments indicate that colon cancer cells are dependent on both ß-catenin-dependent and -independent Wnt signaling routes for growth and proliferation.


Subject(s)
Activating Transcription Factor 2/metabolism , Activating Transcription Factor 4/metabolism , Colonic Neoplasms/pathology , Receptor Tyrosine Kinase-like Orphan Receptors/metabolism , Wnt Proteins/metabolism , Cell Line, Tumor , Cell Proliferation , Gene Expression Regulation, Neoplastic , Humans , Wnt Signaling Pathway , beta Catenin/metabolism
2.
Hepatology ; 68(2): 707-722, 2018 08.
Article in English | MEDLINE | ID: mdl-29059455

ABSTRACT

Postnatal liver development is characterized by hepatocyte growth, proliferation, and functional maturation. Notably, canonical Wnt signaling in hepatocytes has been identified as an important regulator of final adult liver size and metabolic liver zonation. The cellular origin of Wnt ligands responsible for homeostatic liver/body weight ratio (LW/BW) remained unclear, which was also attributable to a lack of suitable endothelial Cre driver mice. To comprehensively analyze the effects of hepatic angiocrine Wnt signaling on liver development and metabolic functions, we used endothelial subtype-specific Stab2-Cre driver mice to delete Wls from hepatic endothelial cells (HECs). The resultant Stab2-Cretg/wt ;Wlsfl/fl (Wls-HECKO) mice were viable, but showed a significantly reduced LW/BW. Specifically, ablation of angiocrine Wnt signaling impaired metabolic zonation in the liver, as shown by loss of pericentral, ß-catenin-dependent target genes such as glutamine synthase (Glul), RhBg, Axin2, and cytochrome P450 2E1, as well as by extended expression of periportal genes such as arginase 1. Furthermore, endothelial subtype-specific expression of a c-terminally YFP-tagged Wls fusion protein in Wls-HECKO mice (Stab2-Cretg/wt ;Wlsfl/fl ;Rosa26:Wls-YFPfl/wt [Wls-rescue]) restored metabolic liver zonation. Interestingly, lipid metabolism was altered in Wls-HECKO mice exhibiting significantly reduced plasma cholesterol levels, while maintaining normal plasma triglyceride and blood glucose concentrations. On the contrary, zonal expression of Endomucin, LYVE1, and other markers of HEC heterogeneity were not altered in Wls-HECKO livers. CONCLUSION: Angiocrine Wnt signaling controls liver growth as well as development of metabolic liver zonation in mice, whereas intrahepatic HEC zonation is not affected. (Hepatology 2017).


Subject(s)
Endothelial Cells/metabolism , Hepatocytes/metabolism , Liver/metabolism , Wnt Signaling Pathway/genetics , Animals , Fluorescent Antibody Technique , Genotyping Techniques , Homeostasis/physiology , Immunohistochemistry , In Situ Hybridization , Lipid Metabolism/physiology , Liver/growth & development , Mice , Mice, Knockout , Real-Time Polymerase Chain Reaction , Wnt Proteins/metabolism
3.
Sci Signal ; 10(461)2017 01 10.
Article in English | MEDLINE | ID: mdl-28074006

ABSTRACT

Wnt signaling plays an important role in the self-renewal and differentiation of stem cells. The secretion of Wnt ligands requires Evi (also known as Wls). Genetically ablating Evi provides an experimental approach to studying the consequence of depleting all redundant Wnt proteins, and overexpressing Evi enables a nonspecific means of increasing Wnt signaling. We generated Evi-deficient and Evi-overexpressing mouse embryonic stem cells (ESCs) to analyze the role of autocrine Wnt production in self-renewal and differentiation. Self-renewal was reduced in Evi-deficient ESCs and increased in Evi-overexpressing ESCs in the absence of leukemia inhibitory factor, which supports the self-renewal of ESCs. The differentiation of ESCs into cardiomyocytes was enhanced when Evi was overexpressed and teratoma formation and growth of Evi-deficient ESCs in vivo were impaired, indicating that autocrine Wnt ligands were necessary for ESC differentiation and survival. ESCs lacking autocrine Wnt signaling had mitotic defects and showed genomic instability. Together, our study demonstrates that autocrine Wnt secretion is important for the survival, chromosomal stability, differentiation, and tumorigenic potential of ESCs.


Subject(s)
Autocrine Communication , Cell Proliferation/genetics , Genomic Instability , Mouse Embryonic Stem Cells/metabolism , Wnt Proteins/genetics , Animals , Cell Differentiation/genetics , Cell Self Renewal , Cell Survival/genetics , Cells, Cultured , Gene Expression Profiling , HEK293 Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Mice , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Knockout , Mouse Embryonic Stem Cells/transplantation , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Wnt Proteins/metabolism , Wnt Signaling Pathway
4.
Stem Cell Res ; 17(3): 607-615, 2016 11.
Article in English | MEDLINE | ID: mdl-27838585

ABSTRACT

Wnt signaling plays a central role in tumor initiation and tumor progression. Mutations in Wnt pathway components, such as the tumor suppressor APC, lead to malignant transformation. While previous studies focused on Wnt-related changes in cancer cells, the impact of aberrant Wnt signaling on the tumor microenvironment is only beginning to emerge. In order to investigate the role of increased Wnt secretion on tumor growth and the microenvironment, we generated a novel germ cell tumor model by overexpressing the Wnt secretion factor Evi/Wls in mouse embryonic stem cells. Evi-overexpressing teratoma were characterized by enhanced tumor growth in supporting a tumor-promoting role of Wnt secretion. Interestingly, enhanced Evi expression correlated with impaired immune cell recruitment. Specifically, T- and B-cell infiltration was reduced in Evi-overexpressing teratomas, which was independent of teratoma size and differentiation. Our study suggests that Wnt secretion impairs immunosurveillance. Since immune cell infiltration has been shown to have prognostic value, the levels of secreted Wnt activity might impact the efficiency of cancer immunotherapy.


Subject(s)
Teratoma/immunology , Teratoma/pathology , Wnt Proteins/metabolism , Animals , Cell Differentiation/physiology , Cell Proliferation/physiology , Embryonic Stem Cells/cytology , Embryonic Stem Cells/immunology , Humans , Mice , Mice, SCID , Teratoma/metabolism , Wnt Proteins/immunology
5.
Dev Cell ; 36(1): 79-93, 2016 Jan 11.
Article in English | MEDLINE | ID: mdl-26766444

ABSTRACT

The WNT signaling enhancer R-spondin3 (RSPO3) is prominently expressed in the vasculature. Correspondingly, embryonic lethality of Rspo3-deficient mice is caused by vessel remodeling defects. Yet the mechanisms underlying vascular RSPO3 function remain elusive. Inducible endothelial Rspo3 deletion (Rspo3-iECKO) resulted in perturbed developmental and tumor vascular remodeling. Endothelial cell apoptosis and vascular pruning led to reduced microvessel density in Rspo3-iECKO mice. Rspo3-iECKO mice strikingly phenocopied the non-canonical WNT signaling-induced vascular defects of mice deleted for the WNT secretion factor Evi/Wls. An endothelial screen for RSPO3 and EVI/WLS co-regulated genes identified Rnf213, Usp18, and Trim30α. RNF213 targets filamin A and NFAT1 for proteasomal degradation attenuating non-canonical WNT/Ca(2+) signaling. Likewise, USP18 and TRIM5α inhibited NFAT1 activation. Consequently, NFAT protein levels were decreased in endothelial cells of Rspo3-iECKO mice and pharmacological NFAT inhibition phenocopied Rspo3-iECKO mice. The data identify endothelial RSPO3-driven non-canonical WNT/Ca(2+)/NFAT signaling as a critical maintenance pathway of the remodeling vasculature.


Subject(s)
Endothelial Cells/metabolism , Gene Expression Regulation, Developmental/genetics , Signal Transduction/genetics , Thrombospondins/metabolism , Transcription Factors/metabolism , Animals , Calcium/metabolism , Mice, Transgenic , NFATC Transcription Factors/metabolism , Thrombospondins/genetics , Wnt Proteins/metabolism
6.
J Immunol ; 195(11): 5261-71, 2015 Dec 01.
Article in English | MEDLINE | ID: mdl-26512137

ABSTRACT

Wnt signaling has been implicated in T cell development. However, it remained unclear which cell type is the major source of Wnt ligands and to what extent thymic epithelial cell (TEC) development is dependent on Wnt signaling. In this study, we analyzed the role of Wnt ligands provided by TECs for the development of T cells and TECs without manipulating the intracellular Wnt signaling machinery in either cell type. To this end, we used conditional knockout mice (FoxN1-Gpr177) in which TECs are unable to secrete Wnt ligands. Gpr177 (Evi/Wls) is a Wnt-specific cargo receptor that is required for the secretion of Wnt ligands. We found that TECs are the main source of Wnt ligands in the thymus, which serves a nonredundant role, and lack of TEC-provided Wnt ligands led to thymic hypotrophy, as well as a reduced peripheral T cell pool. Despite being reduced in numbers, T cells that developed in the absence of TEC-secreted Wnt ligands were functionally competent, and the subset composition of the peripheral T cell pool was not affected. Thus, our data suggest that T cell development is not directly dependent on TEC-provided Wnt ligands. Rather, TEC-secreted Wnt ligands are essential for normal thymus development and normal peripheral T cell frequencies but are dispensable for T cell function in the periphery.


Subject(s)
Lymphocyte Activation/immunology , T-Lymphocytes/cytology , Thymus Gland/immunology , Wnt Proteins/metabolism , Animals , Cell Differentiation/immunology , Epithelial Cells/immunology , Forkhead Transcription Factors/genetics , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Receptors, G-Protein-Coupled/genetics , T-Lymphocytes/immunology , Wnt Signaling Pathway/immunology
7.
J Dtsch Dermatol Ges ; 13(4): 302-6, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25819237

ABSTRACT

The mammalian skin mediates the primary interphase between the body and the external environment and provides the first line of defense against pathogens, mechanical trauma, sunlight injuries, and chemical stress. Proper physical, biochemical, and immunological composition of the skin is necessary to maintain its barrier function. Therefore, the skin reflects a complex dynamic organ with high cellular turnover during normal tissue replacement and wound repair. Stem cell reservoirs ensure constant skin renewal. Wnt signaling controls stem cell maintenance and fate decisions in various tissues and also reflects a key pathway in controlling skin development and homeostasis. Disruption of Wnt signaling in the skin causes disorders such as alopecia, chronic inflammatory skin diseases or cancer. This review summarizes the role of Wnt signaling during skin development, homeostasis, and disease.


Subject(s)
Homeostasis , Skin Diseases/metabolism , Skin Diseases/pathology , Skin/metabolism , Stem Cells/metabolism , Wnt Signaling Pathway , Animals , Humans , Models, Biological , Skin/pathology
8.
Development ; 141(8): 1757-66, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24715464

ABSTRACT

Multiple cell types involved in the regulation of angiogenesis express Wnt ligands. Although ß-catenin dependent and independent Wnt signaling pathways have been shown to control angiogenesis, the contribution of individual cell types to activate these downstream pathways in endothelial cells (ECs) during blood vessel formation is still elusive. To investigate the role of ECs in contributing Wnt ligands for regulation of blood vessel formation, we conditionally deleted the Wnt secretion factor Evi in mouse ECs (Evi-ECKO). Evi-ECKO mice showed decreased microvessel density during physiological and pathological angiogenesis in the postnatal retina and in tumors, respectively. The reduced microvessel density resulted from increased vessel regression accompanied by decreased EC survival and proliferation. Concomitantly, survival-related genes were downregulated and cell cycle arrest- and apoptosis-inducing genes were upregulated. EVI silencing in cultured HUVECs showed similar target gene regulation, supporting a mechanism of EC-derived Wnt ligands in controlling EC function. ECs preferentially expressed non-canonical Wnt ligands and canonical target gene expression was unaffected in Evi-ECKO mice. Furthermore, the reduced vascularization of Matrigel plugs in Evi-ECKO mice could be rescued by introduction of non-canonical Wnt5a. Treatment of mouse pups with the non-canonical Wnt inhibitor TNP470 resulted in increased vessel regression accompanied by decreased EC proliferation, thus mimicking the proliferation-dependent Evi-ECKO remodeling phenotype. Taken together, this study identified EC-derived non-canonical Wnt ligands as regulators of EC survival, proliferation and subsequent vascular pruning during developmental and pathological angiogenesis.


Subject(s)
Endothelial Cells/metabolism , Neovascularization, Pathologic/metabolism , Neovascularization, Physiologic , Wnt Proteins/metabolism , Animals , Animals, Newborn , Apoptosis/drug effects , Apoptosis/genetics , Autocrine Communication/drug effects , Autocrine Communication/genetics , Cell Count , Cell Proliferation/drug effects , Cell Survival/drug effects , Cyclohexanes/pharmacology , DNA-Binding Proteins/metabolism , Endothelial Cells/drug effects , Gene Expression Regulation/drug effects , Human Umbilical Vein Endothelial Cells/drug effects , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Ligands , MDS1 and EVI1 Complex Locus Protein , Mice , Mice, Transgenic , Models, Biological , Neovascularization, Pathologic/genetics , Neovascularization, Pathologic/pathology , Neovascularization, Physiologic/drug effects , Neovascularization, Physiologic/genetics , O-(Chloroacetylcarbamoyl)fumagillol , Phenotype , Proto-Oncogenes , Retina/growth & development , Retina/metabolism , Sesquiterpenes/pharmacology , Signal Transduction/drug effects , Signal Transduction/genetics , Transcription Factors/metabolism
9.
Nat Commun ; 4: 2610, 2013.
Article in English | MEDLINE | ID: mdl-24162018

ABSTRACT

Aberrant regulation of the Wnt/ß-catenin pathway has an important role during the onset and progression of colorectal cancer, with over 90% of cases of sporadic colon cancer featuring mutations in APC or ß-catenin. However, it has remained a point of controversy whether these mutations are sufficient to activate the pathway or require additional upstream signals. Here we show that colorectal tumours express elevated levels of Wnt3 and Evi/Wls/GPR177. We found that in colon cancer cells, even in the presence of mutations in APC or ß-catenin, downstream signalling remains responsive to Wnt ligands and receptor proximal signalling. Furthermore, we demonstrate that truncated APC proteins bind ß-catenin and key components of the destruction complex. These results indicate that cells with mutations in APC or ß-catenin depend on Wnt ligands and their secretion for a sufficient level of ß-catenin signalling, which potentially opens new avenues for therapeutic interventions by targeting Wnt secretion via Evi/Wls.


Subject(s)
Adenocarcinoma/genetics , Adenomatous Polyposis Coli Protein/genetics , Colonic Neoplasms/genetics , Gene Expression Regulation, Neoplastic , Intracellular Signaling Peptides and Proteins/genetics , Receptors, G-Protein-Coupled/genetics , Wnt3 Protein/genetics , beta Catenin/genetics , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Adenomatous Polyposis Coli Protein/metabolism , Animals , Cell Line, Tumor , Cell Proliferation , Colon/metabolism , Colon/pathology , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Mice , Mice, Inbred NOD , Mutation , Neoplasm Transplantation , Receptor, EphB2/genetics , Receptor, EphB2/metabolism , Receptors, G-Protein-Coupled/metabolism , Signal Transduction , Wnt3 Protein/metabolism , beta Catenin/metabolism
10.
J Exp Med ; 210(9): 1761-77, 2013 Aug 26.
Article in English | MEDLINE | ID: mdl-23918954

ABSTRACT

Cells of the epidermis renew constantly from germinal layer stem cells. Although epithelial cell differentiation has been studied in great detail and the role of Wnt signaling in this process is well described, the contribution of epidermal Wnt secretion in epithelial cell homeostasis remains poorly understood. To analyze the role of Wnt proteins in this process, we created a conditional knockout allele of the Wnt cargo receptor Evi/Gpr177/Wntless and studied mice that lacked Evi expression in the epidermis. We found that K14-Cre, Evi-LOF mice lost their hair during the first hair cycle, showing a reddish skin with impaired skin barrier function. Expression profiling of mutant and wild-type skin revealed up-regulation of inflammation-associated genes. Furthermore, we found that Evi expression in psoriatic skin biopsies is down-regulated, suggesting that Evi-deficient mice developed skin lesions that resemble human psoriasis. Immune cell infiltration was detected in Evi-LOF skin. Interestingly, an age-dependent depletion of dendritic epidermal T cells (DETCs) and an infiltration of γδ(low) T cells in Evi mutant epidermis was observed. Collectively, the described inflammatory skin phenotype in Evi-deficient mice revealed an essential role of Wnt secretion in maintaining normal skin homeostasis by enabling a balanced epidermal-dermal cross talk, which affects immune cell recruitment and DETC survival.


Subject(s)
Dermatitis/pathology , Epidermis/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Psoriasis/pathology , Receptors, G-Protein-Coupled/metabolism , Animals , CD3 Complex/metabolism , Cell Proliferation , Chronic Disease , Dendritic Cells/pathology , Dermatitis/complications , Dermatitis/immunology , Dermatitis/metabolism , Epidermis/immunology , Epidermis/pathology , Gene Deletion , Humans , Inflammation/complications , Inflammation/metabolism , Inflammation/pathology , Keratinocytes/metabolism , Keratinocytes/pathology , Keratins/metabolism , Lymphocyte Activation/immunology , Mice , Mice, Transgenic , Neutrophil Infiltration , Phenotype , Psoriasis/complications , Psoriasis/immunology , Psoriasis/metabolism , Receptors, Antigen, T-Cell, gamma-delta/metabolism , STAT3 Transcription Factor/metabolism , T-Lymphocytes/pathology , Wnt Proteins/metabolism
11.
Mol Med ; 19: 135-48, 2013 Jul 24.
Article in English | MEDLINE | ID: mdl-23698091

ABSTRACT

Anxiety disorders and substance abuse, including benzodiazepine use disorder, frequently occur together. Unfortunately, treatment of anxiety disorders still includes benzodiazepines, and patients with an existing comorbid benzodiazepine use disorder or a genetic susceptibility for benzodiazepine use disorder may be at risk of adverse treatment outcomes. The identification of genetic predictors for anxiety disorders, and especially for benzodiazepine use disorder, could aid the selection of the best treatment option and improve clinical outcomes. The brain-specific angiogenesis inhibitor I-associated protein 3 (Baiap3) is a member of the mammalian uncoordinated 13 (Munc13) protein family of synaptic regulators of neurotransmitter exocytosis, with a striking expression pattern in amygdalae, hypothalamus and periaqueductal gray. Deletion of Baiap3 in mice leads to enhanced seizure propensity and increased anxiety, with the latter being more pronounced in female than in male animals. We hypothesized that genetic variation in human BAIAP3 may also be associated with anxiety. By using a phenotype-based genetic association study, we identified two human BAIAP3 single-nucleotide polymorphism risk genotypes (AA for rs2235632, TT for rs1132358) that show a significant association with anxiety in women and, surprisingly, with benzodiazepine abuse in men. Returning to mice, we found that male, but not female, Baiap3 knockout (KO) mice develop tolerance to diazepam more quickly than control animals. Analysis of cultured Baiap3 KO hypothalamus slices revealed an increase in basal network activity and an altered response to diazepam withdrawal. Thus, Baiap3/BAIAP3 is gender specifically associated with anxiety and benzodiazepine use disorder, and the analysis of Baiap3/BAIAP3-related functions may help elucidate mechanisms underlying the development of both disorders.


Subject(s)
Anxiety/genetics , Diazepam/administration & dosage , Midazolam/administration & dosage , Nerve Tissue Proteins/physiology , Substance-Related Disorders/genetics , Animals , Anti-Anxiety Agents/administration & dosage , Anticonvulsants/administration & dosage , Anxiety/physiopathology , Behavior, Animal , Female , Humans , Hypothalamus/physiology , Leukocytes, Mononuclear/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Pentylenetetrazole , Polymorphism, Single Nucleotide , Psychomotor Performance , Seizures/chemically induced , Seizures/genetics , Seizures/physiopathology , Sex Factors , Substance-Related Disorders/physiopathology , Substance-Related Disorders/psychology
12.
EMBO Mol Med ; 4(1): 38-51, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22147553

ABSTRACT

Malignant astrocytomas are highly aggressive brain tumours with poor prognosis. While a number of structural genomic changes and dysregulation of signalling pathways in gliomas have been described, the identification of biomarkers and druggable targets remains an important task for novel diagnostic and therapeutic approaches. Here, we show that the Wnt-specific secretory protein Evi (also known as GPR177/Wntless/Sprinter) is overexpressed in astrocytic gliomas. Evi/Wls is a core Wnt signalling component and a specific regulator of pan-Wnt protein secretion, affecting both canonical and non-canonical signalling. We demonstrate that its depletion in glioma and glioma-derived stem-like cells led to decreased cell proliferation and apoptosis. Furthermore, Evi/Wls silencing in glioma cells reduced cell migration and the capacity to form tumours in vivo. We further show that Evi/Wls overexpression is sufficient to promote downstream Wnt signalling. Taken together, our study identifies Evi/Wls as an essential regulator of glioma tumourigenesis, identifying a pathway-specific protein trafficking factor as an oncogene and offering novel therapeutic options to interfere with the aberrant regulation of growth factors at the site of production.


Subject(s)
Brain Neoplasms/metabolism , Cell Transformation, Neoplastic , Glioma/pathology , Intracellular Signaling Peptides and Proteins/metabolism , Receptors, G-Protein-Coupled/metabolism , Wnt Proteins/metabolism , Animals , Apoptosis , Brain Neoplasms/pathology , Cell Cycle Checkpoints , Cell Line, Tumor , Cell Movement , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/metabolism , Glioma/metabolism , Humans , Interleukins/metabolism , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Nude , RNA Interference , RNA, Small Interfering/metabolism , Receptors, G-Protein-Coupled/antagonists & inhibitors , Receptors, G-Protein-Coupled/genetics , Signal Transduction , Transcriptome , Transplantation, Heterologous
13.
Neuron ; 33(3): 411-24, 2002 Jan 31.
Article in English | MEDLINE | ID: mdl-11832228

ABSTRACT

Presynaptic short-term plasticity is an important adaptive mechanism regulating synaptic transmitter release at varying action potential frequencies. However, the underlying molecular mechanisms are unknown. We examined genetically defined and functionally unique axonal subpopulations of synapses in excitatory hippocampal neurons that utilize either Munc13-1 or Munc13-2 as synaptic vesicle priming factor. In contrast to Munc13-1-dependent synapses, Munc13-2-driven synapses show pronounced and transient augmentation of synaptic amplitudes following high-frequency stimulation. This augmentation is caused by a Ca(2+)-dependent increase in release probability and releasable vesicle pool size, and requires phospholipase C activity. Thus, differential expression of Munc13 isoforms at individual synapses represents a general mechanism that controls short-term plasticity and contributes to the heterogeneity of synaptic information coding.


Subject(s)
Nerve Tissue Proteins/metabolism , Neuronal Plasticity/physiology , Neurons/metabolism , Synaptic Transmission/physiology , Synaptic Vesicles/metabolism , Animals , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Calcium/metabolism , Cells, Cultured , Dizocilpine Maleate/pharmacology , Electric Stimulation , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Excitatory Amino Acid Antagonists/pharmacology , Excitatory Postsynaptic Potentials/physiology , Glutamic Acid/metabolism , Hippocampus/cytology , Hippocampus/metabolism , Intracellular Signaling Peptides and Proteins , Mice , Mice, Knockout , N-Methylaspartate/pharmacology , Nerve Tissue Proteins/genetics , Neurons/cytology , Neurons/drug effects , Protein Isoforms/genetics , Protein Isoforms/metabolism , Thiazoles/pharmacology , Thiazolidines , Type C Phospholipases/antagonists & inhibitors , Type C Phospholipases/metabolism , alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
14.
Cell ; 108(1): 121-33, 2002 Jan 11.
Article in English | MEDLINE | ID: mdl-11792326

ABSTRACT

Munc13-1 is a presynaptic protein with an essential role in synaptic vesicle priming. It contains a diacylglycerol (DAG)/beta phorbol ester binding C(1) domain and is a potential target of the DAG second messenger pathway that may act in parallel with PKCs. Using genetically modified mice that express a DAG/beta phorbol ester binding-deficient Munc13-1(H567K) variant instead of the wild-type protein, we determined the relative contribution of PKCs and Munc13-1 to DAG/beta phorbol ester-dependent regulation of neurotransmitter release. We show that Munc13s are the main presynaptic DAG/beta phorbol ester receptors in hippocampal neurons. Modulation of Munc13-1 activity by second messengers via the DAG/beta phorbol ester binding C(1) domain is essential for use-dependent alterations of synaptic efficacy and survival.


Subject(s)
Diglycerides/metabolism , Nerve Tissue Proteins/metabolism , Phorbol Esters/pharmacology , Protein Kinase C/metabolism , Synaptic Transmission/physiology , Amino Acid Sequence , Animals , Base Sequence , Binding Sites/genetics , Cells, Cultured , Gene Expression/physiology , Hippocampus/cytology , Intracellular Signaling Peptides and Proteins , Mice , Molecular Sequence Data , Mutagenesis/physiology , Nerve Tissue Proteins/genetics , Neurons/cytology , Point Mutation/physiology , Protein Kinase C/genetics , Synapses/enzymology , Synaptic Transmission/drug effects
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