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Signaling through focal adhesion kinase
1Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
Abstract:
Focal adhesion kinase (FAK) is a nonreceptor protein-tyrosine kinase implicated in controlling cellular responses to the engagement of cell-surface integrins, including cell spreading and migration, survival and proliferation. Aberrant FAK signaling may contribute to the process of cell transformation by certain oncoproteins, including v-Src. Progress toward elucidating the events leading to FAK activation following integrin-mediated cell adhesion, as well as events downstream of FAK, has come through the identification of FAK phosphorylation sites and interacting proteins. A signaling partnership is formed between FAK and Src-family kinases, leading to tyrosine phosphorylation of FAK and associated 'docking' proteins Cas and paxillin. Subsequent recruitment of proteins containing Src homology 2 domains, including Grb2 and c-Crk, to the complex is likely to trigger adhesion-induced cellular responses, including changes to the actin cytoskeleton and activation of the Ras-MAP kinase pathway.
Insights
Focal adhesion kinase (FAK) is crucial for cell adhesion and migration. Its signaling partnership with Src-family kinases activates pathways essential for cellular responses and proliferation.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Focal adhesion kinase (FAK) is a key protein-tyrosine kinase regulating cellular responses to integrin engagement.
- FAK signaling is implicated in cell spreading, migration, survival, and proliferation.
- Dysregulated FAK signaling can contribute to cell transformation by oncoproteins like v-Src.
Purpose of the Study:
- To elucidate the mechanisms of FAK activation following integrin-mediated cell adhesion.
- To identify key phosphorylation sites and protein interactions in FAK signaling pathways.
- To understand the downstream events triggered by FAK activation.
Main Methods:
- Identification of FAK phosphorylation sites.
- Analysis of FAK protein-protein interactions.
- Investigation of signaling partnerships with Src-family kinases.
Main Results:
- A signaling complex involving FAK, Src-family kinases, Cas, and paxillin was identified.
- Tyrosine phosphorylation of FAK and associated docking proteins occurs.
- Recruitment of SH2 domain-containing proteins like Grb2 and c-Crk to the complex was observed.
Conclusions:
- FAK forms a critical signaling partnership with Src-family kinases.
- This complex initiates adhesion-induced cellular responses.
- Activation of the Ras-MAP kinase pathway is a downstream consequence of FAK signaling.