[PDF][PDF] Nuclear FAK promotes cell proliferation and survival through FERM-enhanced p53 degradation

ST Lim, XL Chen, Y Lim, DA Hanson, TT Vo… - Molecular cell, 2008 - cell.com
ST Lim, XL Chen, Y Lim, DA Hanson, TT Vo, K Howerton, N Larocque, SJ Fisher…
Molecular cell, 2008cell.com
FAK is known as an integrin-and growth factor-associated tyrosine kinase promoting cell
motility. Here we show that, during mouse development, FAK inactivation results in p53-and
p21-dependent mesodermal cell growth arrest. Reconstitution of primary FAK−/− p21−/−
fibroblasts revealed that FAK, in a kinase-independent manner, facilitates p53 turnover via
enhanced Mdm2-dependent p53 ubiquitination. p53 inactivation by FAK required FAK
FERM F1 lobe binding to p53, FERM F2 lobe-mediated nuclear localization, and FERM F3 …
Summary
FAK is known as an integrin- and growth factor-associated tyrosine kinase promoting cell motility. Here we show that, during mouse development, FAK inactivation results in p53- and p21-dependent mesodermal cell growth arrest. Reconstitution of primary FAK−/−p21−/− fibroblasts revealed that FAK, in a kinase-independent manner, facilitates p53 turnover via enhanced Mdm2-dependent p53 ubiquitination. p53 inactivation by FAK required FAK FERM F1 lobe binding to p53, FERM F2 lobe-mediated nuclear localization, and FERM F3 lobe for connections to Mdm2 and proteasomal degradation. Staurosporine or loss of cell adhesion enhanced FERM-dependent FAK nuclear accumulation. In primary human cells, FAK knockdown raised p53-p21 levels and slowed cell proliferation but did not cause apoptosis. Notably, FAK knockdown plus cisplatin triggered p53-dependent cell apoptosis, which was rescued by either full-length FAK or FAK FERM re-expression. These studies define a scaffolding role for nuclear FAK in facilitating cell survival through enhanced p53 degradation under conditions of cellular stress.
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