[Abstract]  [Full Text]  [PDF]

Wenjie Bao^1* and Staffan Strömblad¹

¹ Karolinska Institutet, Department of Microbiology, Pathology and Immunology. Huddinge University Hospital F46, SE-141 86 Huddinge. Sweden. Phone: 46-8-58581036 Fax: 46-8-58581020

* To whom correspondence should be addressed: Wenjie Bao, Karolinska Institutet, Department of Microbiology, Pathology and Immunology. Huddinge University Hospital F46, SE-141 86 Huddinge. Sweden. Phone: 46-8-58581036. Fax: 46-8-58581020. Email: wenjie.bao@impi.ki.se

Biol. Proced. Online 2002;4:81-87. doi:10.1251/bpo37
Submitted: September 12, 2002; Accepted: October 15, 2002; Published: November 11, 2002.

Indexing terms: cell adhesion; integrins; antibodies, monoclonal; fibronectins; protein kinases.

Cell attachment to the extracellular matrix (ECM) engages integrin signaling into the cell, but part of the signaling response also stem from cell spreading (3). To analyze specific integrin signaling-mediated responses independent of cell spreading, we developed a method engaging integrin signaling by use of an immobilized anti-integrin monoclonal antibody (mab) directed against the fibronectin (FN) receptor integrin α5β1. ECV 304 cells were plated onto FN or immobilized mab JBS5 (anti-integrin α5β1) or onto poly-L-lysin (P-L-L), which mediates integrin-independent attachment. Cells attached and spread on FN, while cells on JBS5 or P-L-L attached but did not spread. Importantly, plating onto FN or mab JBS5 gave rise to identical integrin-induced responses, including a down-regulation of the cyclin-dependent kinase (Cdk2) inhibitors p21^CIP1 and p27^KIP1, while attachment to P-L-L did not. We conclude that engagement of the FN-receptor integrin α5β1 induces integrin signaling regulating the Cdk2-inhibitors independent of cell spreading and present a method for how integrin signaling can be analyzed separate from the effects of cell spreading.