Paxillin is a 70 kDa protein localized to focal adhesions, points of attachment of the cell to the substratum. Tyrosine phosphorylation of paxillin and p125FAK, another focal adhesion protein, is stimulated by a number of different viral and cellular agents. Recent studies, performed by the applicant as a Postdoctoral Fellow, indicate that p125FAK and paxillin interact, and that pp125FAK can phosphorylate paxillin. The central hypothesis of the proposed research is that pp125FAK mediated tyrosine phosphorylation of paxillin regulates the formation of signaling complexes, by recruiting SH2 containing proteins.
Four specific Aims are described. Sequences within pp125FAK and paxillin which mediate protein:protein interaction will be defined using the yeast two-hybrid method (Aim I). Next, the sites of Src and FAK-mediated phosphorylation on paxillin will be altered by mutating tyrosines to phenylalanines, and the ability of the mutated paxillin proteins to bind SH2 domains of known proteins will be assessed (Aim II).
In Aim III, proteins that bind to paxillin, both known and unknown will be examined. Finally, the importance of paxillin containing signaling complexes will be determined by disrupting SH2-containing protein complexes bound to tyrosine phosphorylated paxillin. The effects on cell transformation and cell migration will be studied.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29GM053666-04
Application #
2771037
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1995-09-30
Project End
2000-08-31
Budget Start
1998-09-01
Budget End
1999-08-31
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Schaller, M D; Schaefer, E M (2001) Multiple stimuli induce tyrosine phosphorylation of the Crk-binding sites of paxillin. Biochem J 360:57-66
Schaller, M D (2000) UNC112. A new regulator of cell-extracellular matrix adhesions? J Cell Biol 150:F9-F11
Shen, Y; Lyons, P; Cooley, M et al. (2000) The noncatalytic domain of protein-tyrosine phosphatase-PEST targets paxillin for dephosphorylation in vivo. J Biol Chem 275:1405-13
Shen, Y; Schneider, G; Cloutier, J F et al. (1998) Direct association of protein-tyrosine phosphatase PTP-PEST with paxillin. J Biol Chem 273:6474-81
Schaller, M D (1997) Signaling through the focal adhesion kinase. Soc Gen Physiol Ser 52:241-55