Syndecan-4 Proteoglycan Regulates the Distribution and Activity of Protein Kinase C

摘要: During cell-matrix adhesion, both tyrosine and serine/threonine kinases are activated. Integrin ligation correlates with phosphorylation, whereas the later stages of spreading focal adhesion stress fiber formation in primary fibroblasts requires interactions cell surface proteoglycan heparin-binding moieties. This protein kinase C (PKC) activation, PKCα can become localized to adhesions normal, but not transformed, cells. PKC activation has been thought be downstream initial receptor-ligand interactions. We now show, however, that syndecan-4 transmembrane heparan sulfate co-immunoprecipitate co-patch vivo. The core directly bind catalytic domain potentiate its by phospholipid mediators. It also activate absence other activity resides sequence LGKKPIYKK center short cytoplasmic domain, syndecans lack this regulatory properties. Syndecan-4 is a component, interaction may localize amplify at sites forming adhesions. represents first report direct signaling through proteoglycans.