PDGF RECEPTOR-TO-NUCLEUS SIGNALING OF P91 (STAT1-ALPHA) TRANSCRIPTIONFACTOR IN RAT SMOOTH-MUSCLE CELLS

Vascular smooth muscle cells (VSMC) are the predominant cell type in t he media of a normal artery. Injury to the vessel wall leads to platel et deposition and the release of numerous factors, including PDGF, whi ch exerts its biological effects by binding to specific surface recept ors on the smooth muscle cell membrane. We demonstrate that PDGF-stimu lated smooth muscle cells activate the STAT (signal transducers and ac tivators of transcription) family of proteins in addition to other sig naling pathways (e.g., RAS-RAF-MAP Kinase). We show that the transcrip tion factor p91 (STAT1 alpha) is rapidly activated by PDGF in VSMC and specifically binds to the regulatory elements SIE or GAS, We hypothes ize that signal transduction by p91 plays an important role in VSMC, e specially after injury with the release of growth factors such as PDGF . (C) 1996 Academic Press, Inc.