Dynamic conformational changes in the FERM domain of FAK are involved in focal-adhesion behavior during cell spreading and motility

PAPUSHEVA, E., F. M. DE QUEIRO, J. DALOUS, Y. HAN, A. ESPOSITO, E. A. JARES-ERIJMAN, T. M. JOVIN AND G. BUNT

JOURNAL OF CELL SCIENCE

COMPANY OF BIOLOGISTS LTD

Año: 2009 vol. 122 p. 656 - 666

0021-9533

Focal adhesion kinase (FAK) controls cellular adhesion and motility processes by its tight link to integrin-and extracellular- matrix-mediated signaling. To explore the dynamics of the regulation of FAK, we constructed a FRET-based probe that visualizes conformational rearrangements of the FERM domain of FAK in living cells. The sensor reports on an integrin- mediated conformational change in FAK following cellular adhesion. The perturbation is kinase-independent and involves the polybasic KAKTLR sequence in the FERM domain. It is manifested by an increased FRET signal and is expressed primarily in focal adhesions, and to a lesser extent in the cytoplasm. The conformational change in the FERM domain of FAK is observed in two consecutive phases during spreading – early and late – and is enriched in fully adhered motile cells at growing and sliding peripheral focal-adhesion sites, but not in stable or retracting focal adhesions. Inhibition of the actomyosin system indicates the involvement of tension signaling induced by Rho-associated kinase, rather than by myosin light- chain kinase, in the modulation of the FERM response. We conclude that the heterogeneous conformation of the FERM domain in focal adhesions of migrating cells reflects a complex regulatory mechanism for FAK that appears to be under the influence of cellular traction forces.