TIMP-2 upregulates RECK expression via dephosphorylation of paxillin tyrosine residues 31 and 118.
We previously demonstrated that TIMP-2 increases the association of Crk with C3G and via subsequent activation of Rap1 enhances the expression of RECK, a membrane-anchored MMP inhibitor. In the present study, we investigate the mechanism of how the TIMP-2 signal is transduced from the alpha3beta1 integrin receptor to the Crk-C3G-Rap1 molecular complex. TIMP-2 treatment of human microvascular endothelial cells (hMVECs) increased the phosphorylation levels of Src at Tyr-527, the negative regulatory site, through enhanced association of Src with Csk. This results in the reduction of Src kinase activity and dephosphorylation of paxillin at Tyr-31/118, the target sites for Src kinase phosphorylation and also the binding sites for the downstream effector Crk. Such TIMP-2 effects accompany the disassembly of paxillin-Crk-DOCK180 molecular complex and, in turn, Rac1 inactivation. On the contrary, levels of paxillin-Crk-C3G complex formation are not reduced, rather slightly increased, which is consistent with our previous finding. Therefore, TIMP-2-mediated inhibition of Src kinase activity leads to the signaling switch from Rac1 to Rap1, thereby leading to enhanced RECK expression.
Oh
J
J
Laboratory of Cellular Oncology, Korea University Graduate School of Medicine, Ansan, Gyeonggi do, Korea. ohjs@korea.ac.kr
Diaz
T
T
Wei
B
B
Chang
H
H
Noda
M
M
Stetler-Stevenson
W G
WG
D002478:Cells, Cultured; D058851:GPI-Linked Proteins; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D051419:Paxillin / Q000378:metabolism*; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000502:physiology*; D014443:Tyrosine / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology*; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D020827:rap1 GTP-Binding Proteins / Q000502:physiology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors
D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D051419:Paxillin; C115460:RECK protein, human; D019716:Tissue Inhibitor of Metalloproteinase-2; D014443:Tyrosine; D019061:src-Family Kinases; D020830:rac1 GTP-Binding Protein; D020827:rap1 GTP-Binding Proteins