Andrew Chang
B.A./M.A. Harvard University, 2007

1st Year Graduate Student

Advisor: Peter Tonge, Ph.D.

Department: Chemistry

Graduate Program: Chemistry

Abstract (rotation):

Advisor: Dr. W. Todd Miller, Dept. of Physiology and Biophysics, SBU

Title:  Effects of a Src SH2 mutant on the phosphorylation of wild-type Cas

Cas is a multidomain signaling protein found in focal adhesions. Phosphorylation of Cas plays a major role in regulating cell migration and the actin cytoskeleton. This lab has previously demonstrated that the multisite phosphorylation of Cas occurs processively. It has also shown that the Src SH3 domain is required for its interaction with Cas. However, further details concerning the mechanism of processivity are still unclear. One possibility is that Src "hops" along successively phosphorylated sites on Cas via its SH2 domain. To test this possibility, Src mutant R175L, which has a non-functioning SH2 domain, was expressed and purified. The activity and kinetics of phosphorylation were determined via gel-shift and pulse-chase assays with wild-type Cas. Preliminary results suggest that the Src SH2 domain is not required for the processive phosphorylation of Cas.