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.
Laboratory of Cellular Oncology, Korea University Graduate School of Medicine, Ansan, Gyeonggi do, Korea. ohjs@korea.ac.kr
J
J
Oh
T
T
Diaz
B
B
Wei
H
H
Chang
M
M
Noda
W G
WG
Stetler-Stevenson
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