p120 serine and threonine phosphorylation is controlled by multiple ligand-receptor pathways but not cadherin ligation.

Xia X, Carnahan RH, Vaughan MH, Wildenberg GA, Reynolds AB
Exp Cell Res. 2006 312 (17): 3336-48

PMID: 16935280 · DOI:10.1016/j.yexcr.2006.07.007

p120-catenin (p120) regulates cadherin turnover and is required for cadherin stability. Extensive and dynamic phosphorylation on tyrosine, serine and threonine residues in the N-terminal regulatory domain has been postulated to regulate p120 function, possibly through modulation of the efficiency of p120/cadherin interaction. Here we have utilized novel phospho-specific monoclonal antibodies to four major p120 serine and threonine phosphorylation sites to monitor individual phosphorylation events and their consequences. Surprisingly, membrane-localization and not cadherin interaction is the main determinant in p120 serine and threonine phosphorylation and dephosphorylation. Furthermore, the phospho-status of these four residues had no obvious effect on p120's role in cadherin complex stabilization or cell-cell adhesion. Interestingly, dephosphorylation was dramatically induced by PKC activation, but PKC-independent pathways were also evident. The data suggest that p120 dephosphorylation at these sites is modulated by multiple cell surface receptors primarily through PKC-dependent pathways, but these changes do not seem to reduce p120/cadherin affinity.

MeSH Terms (20)

Amino Acid Substitution Animals Cadherins Catenins Cell Adhesion Molecules Cell Line, Tumor Cell Nucleus Dogs Humans Ligands Mutagenesis, Site-Directed Phosphoproteins Phosphorylation Protein Binding Protein Kinase C Receptors, G-Protein-Coupled RNA, Small Interfering Serine Signal Transduction Threonine

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