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Insulin receptor substrate-1/SHP-2 interaction, a phenotype-dependent switching machinery of insulin-like growth factor-I signaling in vascular smooth muscle cells.

Authors: Hayashi, K  Shibata, K  Morita, T  Iwasaki, K  Watanabe, M  Sobue, K 
Citation: Hayashi K, etal., J Biol Chem. 2004 Sep 24;279(39):40807-18. Epub 2004 Jul 21.
Pubmed: (View Article at PubMed) PMID:15272025
DOI: Full-text: DOI:10.1074/jbc.M405100200

Insulin-like growth factor-I (IGF-I) plays a role in mutually exclusive processes such as proliferation and differentiation in a variety of cell types. IGF-I is a potent mitogen and motogen for dedifferentiated vascular smooth muscle cells (VSMCs) in vivo and in vitro. However, in differentiated VSMCs, IGF-I is only required for maintaining the differentiated phenotype. Here we investigated the VSMC phenotype-dependent signaling and biological processes triggered by IGF-I. In differentiated VSMCs, IGF-I activated a protein-tyrosine phosphatase, SHP-2, recruited by insulin receptor substrate-1 (IRS-1). The activated SHP-2 then dephosphorylated IRS-1 Tyr(P)-895, resulting in blockade of the pathways from IRS-1/Grb2/Sos to the ERK and p38 MAPK. Conversely, such negative regulation was silent in dedifferentiated VSMCs, where IGF-I activated both MAPKs via IRS-1/Grb2/Sos interaction-linked Ras activation, leading to proliferation and migration. Thus, our present results demonstrate that the IRS-1/SHP-2 interaction acts as a switch controlling VSMC phenotype-dependent IGF-I-induced signaling pathways and biological processes, and this mechanism is likely to be applicable to other cells.

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RGD Object Information
RGD ID: 1581313
Created: 2006-09-26
Species: All species
Last Modified: 2006-09-26
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.