Protein phosphatase 1 regulates the phosphorylation state of the polarity scaffold Par-3.

ABSTRACT: Phosphorylation of the polarity protein Par-3 by the serine/threonine kinases aPKCzeta/iota and Par-1 (EMK1/MARK2) regulates various aspects of epithelial cell polarity, but little is known about the mechanisms by which these posttranslational modifications are reversed. We find that the serine/threonine protein phosphatase PP1 (predominantly the alpha isoform) binds Par-3, which localizes to tight junctions in MDCKII cells. PP1alpha can associate with multiple sites on Par-3 while retaining its phosphatase activity. By using a quantitative mass spectrometry-based technique, multiple reaction monitoring, we show that PP1alpha specifically dephosphorylates Ser-144 and Ser-824 of mouse Par-3, as well as a peptide encompassing Ser-885. Consistent with these observations, PP1alpha regulates th

SUBMITTER: Traweger A 

PROVIDER: S-EPMC2475498 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature