The phosphomimetic mutation of syndecan-4 binds and inhibits Tiam1 modulating Rac1 activity in PDZ interaction-dependent manner
| Autor: | Aniko Keller-Pinter, Bettina Ughy, József Tímár, József Tóvári, László Szilák, Mónika Domoki, Tamás Letoha, Aladár Pettkó-Szandtner |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
rac1 GTP-Binding Protein RHOA Hydrolases Mutant lcsh:Medicine PDZ Domains GTPase Biochemistry Syndecan 1 Signaling Molecules Cell Signaling Guanine Nucleotide Exchange Factors T-Lymphoma Invasion and Metastasis-inducing Protein 1 Post-Translational Modification Phosphorylation lcsh:Science Multidisciplinary biology Chemistry Transmembrane protein Cell biology Precipitation Techniques Enzymes Cell Motility MCF-7 Cells Guanine nucleotide exchange factor Research Article Signal Transduction Protein Binding Cell Binding Cell Physiology Protein Kinase C-alpha PDZ domain RAC1 Cell Migration Research and Analysis Methods Transfection Green Fluorescent Protein Models Biological 03 medical and health sciences Immunoprecipitation Humans Amino Acid Sequence Molecular Biology Techniques Molecular Biology rho Guanine Nucleotide Dissociation Inhibitor alpha 030102 biochemistry & molecular biology lcsh:R Biology and Life Sciences Proteins Cell Biology Guanosine Triphosphatase Luminescent Proteins 030104 developmental biology p21-Activated Kinases Mutation biology.protein Enzymology lcsh:Q Syndecan-4 Developmental Biology |
| Zdroj: | PLoS ONE PLoS ONE, Vol 12, Iss 11, p e0187094 (2017) |
| DOI: | 10.1371/journal.pone.0187094 |
| Popis: | The small GTPases of the Rho family comprising RhoA, Rac1 and Cdc42 function as molecular switches controlling several essential biochemical pathways in eukaryotic cells. Their activity is cycling between an active GTP-bound and an inactive GDP-bound conformation. The exchange of GDP to GTP is catalyzed by guanine nucleotide exchange factors (GEFs). Here we report a novel regulatory mechanism of Rac1 activity, which is controlled by a phosphomimetic (Ser179Glu) mutant of syndecan-4 (SDC4). SDC4 is a ubiquitously expressed transmembrane, heparan sulfate proteoglycan. In this study we show that the Ser179Glu mutant binds strongly Tiam1, a Rac1-GEF reducing Rac1-GTP by 3-fold in MCF-7 breast adenocarcinoma cells. Mutational analysis unravels the PDZ interaction between SDC4 and Tiam1 is indispensable for the suppression of the Rac1 activity. Neither of the SDC4 interactions is effective alone to block the Rac1 activity, on the contrary, lack of either of interactions can increase the activity of Rac1, therefore the Rac1 activity is the resultant of the inhibitory and stimulatory effects. In addition, SDC4 can bind and tether RhoGDI1 (GDP-dissociation inhibitor 1) to the membrane. Expression of the phosphomimetic SDC4 results in the accumulation of the Rac1-RhoGDI1 complex. Co-immunoprecipitation assays (co-IP-s) reveal that SDC4 can form complexes with RhoGDI1. Together, the regulation of the basal activity of Rac1 is fine tuned and SDC4 is implicated in multiple ways. |
| Databáze: | OpenAIRE |
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