Bombesin and Platelet-derived Growth Factor Induce Association of Endogenous Focal Adhesion Kinase with Src in Intact Swiss 3T3 Cells

doi:10.1074/jbc.274.40.28371

Bombesin and Platelet-derived Growth Factor Induce Association of Endogenous Focal Adhesion Kinase with Src in Intact Swiss 3T3 Cells*

From the Department of Medicine, School of Medicine and Molecular Biology Institute, UCLA, Los Angeles, California 90095

Abstract

Stimulation of quiescent Swiss 3T3 cells with bombesin induces a rapid increase in the formation of complexes between focal adhesion kinase (FAK) and Src family members, which can be extracted with a buffer containing Triton, deoxycholate, and SDS but not with a buffer containing Triton alone. An increase in complex formation between FAK and Src in response to bombesin could be detected within 1 min, reached a maximum after 10 min, and declined toward base-line levels after 60 min of bombesin treatment. Bradykinin, endothelin, and lysophosphatidic acid also stimulated FAK-Src complex formation. Bombesin stimulated FAK/Src association through a Ca²⁺ and phosphatidylinositol 3′-kinase-independent pathway that requires the integrity of the actin filament network and is partly dependent on functional protein kinase C. Treatment with the selective Src kinase inhibitor PP-2 inhibited both FAK activation and phosphorylation of FAK at Tyr⁵⁷⁷ induced by bombesin in intact cells. Platelet-derived growth factor at low concentrations (1–10 ng/ml) also induced FAK-Src complex formation via a pathway that depended on the integrity of the actin cytoskeleton and phosphatidylinositol 3′-kinase. Thus, G protein-coupled receptor agonists and platelet-derived growth factor promote complex formation between endogenous FAK and Src in attached cells through different signal transduction pathways.

Footnotes

↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵‡ Recipient of a postdoctoral fellowship from Consejo Nacional de Ciencia y Tecnologia, Mexico.
↵§ To whom all correspondence should be addressed: 900 Veteran Ave., Warren Hall Rm. 11-124, Dept. of Medicine, UCLA School of Medicine, Los Angeles, CA 90095-178622. Tel.: 310-794-6610; Fax: 310-267-2399.
Abbreviations:

GPCR

G-protein-coupled receptor

DMEM

Dulbecco’s modified Eagle’s medium

FAK

focal adhesion kinase

LPA

lysophosphatidic acid, Ab, antibody

PAGE

polyacrylamide gel electrophoresis

PDB

phorbol 12,13-dibutyrate

PDGF

platelet-derived growth factor

PI 3-kinase

phosphatidylinositol 3-kinase

PKC

protein kinase C

PP-2

pyrazolopyrimidine 2

SH2 and SH3

Src homology domain 2 and 3, respectively

MAPK

mitogen-activated protein kinase

S6K

S6 kinase
- Received February 26, 1999.
- Revision received June 14, 1999.
The American Society for Biochemistry and Molecular Biology, Inc.