Abstract |
Tyrosine phosphorylation is implicated in regulating the adherens junction protein, p120 catenin (p120), however, the mechanisms are not well defined. Here, we show, using substrate trapping, that p120 is a direct target of the protein tyrosine phosphatase, PTP-PEST, in epithelial cells. Stable shRNA knockdown of PTP-PEST in colon carcinoma cells results in an increased cytosolic pool of p120 concomitant with its enhanced tyrosine phosphorylation and decreased association with E-cadherin. Consistent with this, PTP-PEST knockdown cells exhibit increased motility, enhanced Rac1 and decreased RhoA activity on a collagen substrate. Furthermore, p120 localization is enhanced at actin-rich protrusions and lamellipodia and has an increased association with the guanine nucleotide exchange factor, VAV2, and cortactin. Exchange factor activity of VAV2 is enhanced by PTP-PEST knockdown whereas overexpression of a VAV2 C-terminal domain or DH domain mutant blocks cell motility. Analysis of point mutations identified tyrosine 335 in the N-terminal domain of p120 as the site of PTP-PEST dephosphorylation. A Y335F mutant of p120 failed to induce the 'p120 phenotype', interact with VAV2, stimulate cell motility or activate Rac1. Together, these data suggest that PTP-PEST affects epithelial cell motility by controlling the distribution and phosphorylation of p120 and its availability to control Rho GTPase activity.
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Authors | Rosario Espejo, Yowjiun Jeng, Adriana Paulucci-Holthauzen, William Rengifo-Cam, Krysta Honkus, Panos Z Anastasiadis, Sarita K Sastry |
Journal | Journal of cell science
(J Cell Sci)
Vol. 127
Issue Pt 3
Pg. 497-508
(Feb 01 2014)
ISSN: 1477-9137 [Electronic] England |
PMID | 24284071
(Publication Type: Journal Article, Research Support, N.I.H., Extramural)
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Chemical References |
- p120 GTPase Activating Protein
- Tyrosine
- PTPN12 protein, human
- Protein Tyrosine Phosphatase, Non-Receptor Type 12
- rho GTP-Binding Proteins
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Topics |
- Cell Line, Tumor
- Cell Movement
(genetics)
- Colonic Neoplasms
(genetics, metabolism, pathology)
- Epithelial Cells
- Humans
- Mutation
- Phosphorylation
(genetics)
- Protein Tyrosine Phosphatase, Non-Receptor Type 12
(genetics, metabolism)
- Tyrosine
(genetics)
- p120 GTPase Activating Protein
(genetics, metabolism)
- rho GTP-Binding Proteins
(genetics, metabolism)
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