Dataset Information

Grb2 promotes integrin-induced focal adhesion kinase (FAK) autophosphorylation and directs the phosphorylation of protein tyrosine phosphatase ? by the Src-FAK kinase complex.

ABSTRACT: The integrin-activated Src-focal adhesion kinase (FAK) kinase complex phosphorylates PTP? at Tyr789, initiating PTP?-mediated signaling that promotes cell migration. Recruitment of the BCAR3-Cas complex by PTP?-phospho-Tyr789 at focal adhesions is one mechanism of PTP? signaling. The adaptor protein Grb2 is also recruited by PTP?-phospho-Tyr789, although the role of the PTP?-Grb2 complex in integrin signaling is unknown. We show that silencing Grb2 expression in fibroblasts abolishes PTP?-Tyr789 phosphorylation and that this is due to two unexpected actions of Grb2. First, Grb2 promotes integrin-induced autophosphorylation of FAK-Tyr397. This is impaired in Grb2-depleted cells and prohibits FAK activation and formation of the Src-FAK complex. Grb2-depleted cells contain less paxillin, and paxillin overexpression rescues FAK-Tyr397 phosphorylation, suggesting that the FAK-activating action of Grb2 involves paxillin. A second distinct role for Grb2 in PTP?-Tyr789 phosphorylation involves Grb2-mediated coupling of Src-FAK and PTP?. This requires two phosphosites, FAK-Tyr925 and PTP?-Tyr789, for Grb2-Src homology 2 (SH2) binding. We propose that a Grb2 dimer links FAK and PTP?, and this positions active Src-FAK in proximity with other, perhaps integrin-clustered, molecules of PTP? to enable maximal PTP?-Tyr789 phosphorylation. These findings identify Grb2 as a new FAK activator and reveal its essential role in coordinating PTP? tyrosine phosphorylation to enable downstream integrin signaling and migration.

SUBMITTER: Cheng SY

PROVIDER: S-EPMC3911518 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Grb2 promotes integrin-induced focal adhesion kinase (FAK) autophosphorylation and directs the phosphorylation of protein tyrosine phosphatase α by the Src-FAK kinase complex.

Cheng Suzanne Y S SY Sun Guobin G Schlaepfer David D DD Pallen Catherine J CJ

Molecular and cellular biology 20131118 3

The integrin-activated Src-focal adhesion kinase (FAK) kinase complex phosphorylates PTPα at Tyr789, initiating PTPα-mediated signaling that promotes cell migration. Recruitment of the BCAR3-Cas complex by PTPα-phospho-Tyr789 at focal adhesions is one mechanism of PTPα signaling. The adaptor protein Grb2 is also recruited by PTPα-phospho-Tyr789, although the role of the PTPα-Grb2 complex in integrin signaling is unknown. We show that silencing Grb2 expression in fibroblasts abolishes PTPα-Tyr789 ...[more]

PMID: 24248601

Similar Datasets

Project description:Focal adhesion kinase (FAK) inhibitors have been developed as potential anticancer agents and are undergoing clinical trials. In vitro activation of the FAK kinase domain triggers autophosphorylation of Y397, Src activation, and subsequent phosphorylation of other FAK tyrosine residues. However, how FAK Y397 mutations affect FAK kinase-dead (KD) phenotypes in tumour angiogenesis in vivo is unknown. We developed three Pdgfb-iCreert -driven endothelial cell (EC)-specific, tamoxifen-inducible homozygous mutant mouse lines: FAK wild-type (WT), FAK KD, and FAK double mutant (DM), i.e. KD with a putatively phosphomimetic Y397E mutation. These ECCre+;FAKWT/WT , ECCre+;FAKKD/KD and ECCre+;FAKDM/DM mice were injected subcutaneously with syngeneic B16F0 melanoma cells. Tumour growth and tumour blood vessel functions were unchanged between ECCre+;FAKWT/WT and ECCre-;FAKWT/WT control mice. In contrast, tumour growth and vessel density were decreased in ECCre+;FAKKD/KD and ECCre+;FAKDM/DM mice, as compared with Cre?-?littermates. Despite no change in the percentage of perfused vessels or pericyte coverage in either genotype, tumour hypoxia was elevated in ECCre+;FAKKD/KD and ECCre+;FAKDM/DM mice. Furthermore, although ECCre+;FAKKD/KD mice showed reduced blood vessel leakage, ECCre+;FAKDM/DM and ECCre-;FAKDM/DM mice showed no difference in leakage. Mechanistically, fibronectin-stimulated Y397 autophosphorylation was reduced in Cre+;FAKKD/KD ECs as compared with Cre+;FAKWT/WT cells, with no change in phosphorylation of the known Src targets FAK-Y577, FAK-Y861, FAK-Y925, paxillin-Y118, p130Cas-Y410. Cre+;FAKDM/DM ECs showed decreased Src target phosphorylation levels, suggesting that the Y397E substitution actually disrupted Src activation. Reduced VE-cadherin-pY658 levels in Cre+;FAKKD/KD ECs were rescued in Cre+FAKDM/DM ECs, corresponding with the rescue in vessel leakage in the ECCre+;FAKDM/DM mice. We show that EC-specific FAK kinase activity is required for tumour growth, angiogenesis, and vascular permeability. The ECCre+;FAKDM/DM mice restored the KD-dependent tumour vascular leakage observed in ECCre+;FAKKD/KD mice in vivo. This study opens new fields in in vivo FAK signalling. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Dataset Information

Grb2 promotes integrin-induced focal adhesion kinase (FAK) autophosphorylation and directs the phosphorylation of protein tyrosine phosphatase ? by the Src-FAK kinase complex.

Publications

Grb2 promotes integrin-induced focal adhesion kinase (FAK) autophosphorylation and directs the phosphorylation of protein tyrosine phosphatase α by the Src-FAK kinase complex.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure