| First Author | Hamelers IH | Year | 2005 |
| Journal | J Cell Biol | Volume | 171 |
| Issue | 5 | Pages | 871-81 |
| PubMed ID | 16330714 | Mgi Jnum | J:104526 |
| Mgi Id | MGI:3612226 | Doi | 10.1083/jcb.200509172 |
| Citation | Hamelers IH, et al. (2005) The Rac activator Tiam1 is required for (alpha)3(beta)1-mediated laminin-5 deposition, cell spreading, and cell migration. J Cell Biol 171(5):871-81 |
| abstractText | The Rho-like guanosine triphosphatase Rac1 regulates various signaling pathways, including integrin-mediated adhesion and migration of cells. However, the mechanisms by which integrins signal toward Rac are poorly understood. We show that the Rac-specific guanine nucleotide exchange factor Tiam1 (T-lymphoma invasion and metastasis 1) is required for the integrin-mediated laminin (LN)-5 deposition, spreading, and migration of keratinocytes. In contrast to wild-type keratinocytes, Tiam1-deficient (Tiam1-/-) keratinocytes are unable to adhere to and spread on a glass substrate because they are unable to deposit their own LN5 substrate. Both Tiam1 and V12Rac1 can rescue the defects of Tiam1-/- keratinocytes, indicating that these deficiencies are caused by impaired Tiam1-mediated Rac activation. Tiam1-/- cells are unable to activate Rac upon alpha3beta1-mediated adhesion to an exogenous LN5 substrate. Moreover, Tiam1 deficiency impairs keratinocyte migration in vitro and reepithelialization of excision wounds in mouse skin. Our studies indicate that Tiam1 is a key molecule in alpha3beta1-mediated activation of Rac, which is essential for proper production and secretion of LN5, a requirement for the spreading and migration of keratinocytes. |
