Pressure activates colon cancer cell adhesion via paxillin phosphorylation, Crk, Cas, and Rac1

• Published in: Cellular and molecular life sciences : CMLS Vol. 65; no. 9; pp. 1446 - 1457
• Main Authors: Downey, C, Craig, D. H, Basson, M. D
• Format: Journal Article
• Language: English
• Published: Basel Basel : SP Birkhäuser Verlag Basel 01.05.2008; SP Birkhäuser Verlag Basel; Springer Nature B.V
• Subjects: Actinin - antagonists & inhibitors; Adhesion; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cas; Cell Adhesion; Cell adhesion & migration; Cell Biology; Cell Line, Tumor; Colonic Neoplasms - metabolism; Colonic Neoplasms - pathology; Colorectal cancer; Crk; Crk-Associated Substrate Protein - antagonists & inhibitors; Crk-Associated Substrate Protein - metabolism; Enzymes; Humans; Life Sciences; Metastasis; Neoplasm Metastasis; neoplasms; Paxillin; Paxillin - antagonists & inhibitors; Paxillin - chemistry; Paxillin - metabolism; Phosphorylation; Pressure; Proteins; Proto-Oncogene Proteins c-crk - antagonists & inhibitors; Proto-Oncogene Proteins c-crk - metabolism; Rac1; rac1 GTP-Binding Protein - metabolism; Research Article; RNA Interference; Tumor Cells, Cultured; Tyrosine - metabolism; Cas; cancer; pressure; Rac1; Adhesion; Crk; Paxillin
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s00018-008-8038-x

Physical forces can activate colon cancer cell adhesion, critical for metastasis. Paxillin is phosphorylated by FAK and required for pressure-stimulated adhesion. However, whether paxillin acts as an inert scaffolding protein or whether paxillin phosphorylation is required is unknown. Transfection with paxillin point-phosphorylation mutants demonstrated that phosphorylation at tyrosines 31 and 118 together is necessary for pressure-stimulated adhesion. We further evaluated potential paxillin partners. Reducing the adaptor protein Crk or the focal adhesion protein p130Cas blocked pressure-stimulated adhesion. Furthermore, Crk and p130Cas both displayed increased co-immunoprecipitation with paxillin in response to increased pressure, except in cells transfected with a Y31Y118 paxillin mutant. Inhibiting the small GTPase Rac1 also abolished pressure-stimulated adhesion, and reducing paxillin by siRNA blocked Rac1 phosphorylation by pressure. Thus, paxillin phosphorylation at tyrosines 31 and 118 together is necessary for pressure-induced adhesion. Paxillin, Crk and Cas form a trimeric complex that activates Rac1 and mediates this effect.