Protein complexes involving alpha v beta 3 integrins, nonmuscle myosin heavy chain-A, and focal adhesion kinase from in thrombospondin-treated smooth muscle cells.
alpha v beta 3 integrins have been implicated in regulating vascular healing in animal models of arterial injury. Because the specific cellular events mediated by alpha v beta 3 integrins are not completely understood, we examined alpha v beta 3 integrin-dependent cytoplasmic events in cultured human smooth muscle cells (SMC) following treatment with thrombospondin-1 (TSP), a glycoprotein concentrated at sites of blood vessel injury. TSP treatment elicited a time-dependent association of nonmuscle myosin heavy chain-A (NMHC-A) with alpha v beta 3 integrins. NMHC-A also associated with focal adhesion kinase (FAK) in TSP-treated SMC. FAK, a nonreceptor kinase implicated in integrin-mediated signaling, was phosphorylated on tyrosine in growth-arrested SMC, but levels of tyrosine phosphorylation increased following treatment with TSP. To test whether NMHC-A was regulated by vascular injury, we examined expression in baboon brachial arteries. In uninjured arteries, NMHC-A staining was present in the media. In arteries injured by balloon withdrawal, medial NMHC-A expression was increased with intense staining at specific sites. In summary, heteromeric protein complexes involving alpha v beta 3 integrins, NMHC-A, and FAK form following treatment of human SMC with TSP. These results suggest that the formation of protein signaling complexes is one mechanism whereby alpha v beta 3 integrins influence intracellular signaling pathways.
Sajid
M
M
Sealy Center for Molecular Cardiology, University of Texas Medical Branch, Galveston, USA.
Hu
Z
Z
Lele
M
M
Stouffer
G A
GA
D000818:Animals; D001916:Brachial Artery / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004727:Endothelium / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D008297:Male; D020409:Molecular Motor Proteins; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism*; D010215:Papio; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D019030:Receptors, Vitronectin / Q000378:metabolism*; D015398:Signal Transduction; D019699:Thrombospondins / Q000494:pharmacology*
C103814:MYH9 protein, human; D020409:Molecular Motor Proteins; D019030:Receptors, Vitronectin; D019699:Thrombospondins; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D018995:Myosin Heavy Chains