Comprehensive Analysis of Phosphorylation Sites in Tensin1 Reveals Regulation by

Tensin1 is the archetype of a family of focal adhesion proteins. Tensin1 has a phosphotyrosine binding do-main that binds the cytoplasmic tail of -integrin, a Src homology 2 domain that binds focal adhesion kinase, p130Cas, and the RhoGAP called deleted in liver can-cer-1, a phosphatase and tensin homology domain that binds protein phosphatase-1 and other regions that bind F-actin. The association between tensin1 and these partners affects cell polarization, migration, and inva-sion. In this study we analyzed the phosphorylation of human S-tag-tensin1 expressed in HEK293 cells by mass spectrometry. Peptides covering>90 % of the se-quence initially revealed 50 phosphorylated serine/ phosphorylated threonine (pSer/pThr) but no phosphory-lated tyrosine (pTyr) sites. Addition of peroxyvanadate t