Molecular aspects of arterial smooth muscle contraction: focus on Rho.
The vascular smooth muscle cell is a highly specialized cell whose primary function is contraction and relaxation. It expresses a variety of contractile proteins, ion channels, and signalling molecules that regulate contraction. Upon contraction, vascular smooth muscle cells shorten, thereby decreasing the diameter of a blood vessel to regulate the blood flow and pressure. Contractile activity in vascular smooth muscle cells is initiated by a Ca(2+)-calmodulin interaction to stimulate phosphorylation of the light chain of myosin. Ca(2+)-sensitization of the contractile proteins is signaled by the RhoA/Rho-kinase pathway to inhibit the dephosphorylation of the light chain by myosin phosphatase, thereby maintaining force. Removal of Ca(2+) from the cytosol and stimulation of myoson phosphatase initiate the relaxation of vascular smooth muscle.
Hilgers
Rob H P
RH
Department of Physiology, Medical College of Georgia, Augusta, GA 30912-3000, USA. cwebb@mail.mcg.edu
Webb
R Clinton
RC
D000818:Animals; D001158:Arteries / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology*; D002147:Calmodulin / Q000378:metabolism; D006801:Humans; D009126:Muscle Relaxation / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D018994:Myosin Light Chains / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase / Q000378:metabolism; D010766:Phosphorylation; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D002147:Calmodulin; D018994:Myosin Light Chains; C066737:RHOA protein, human; D043263:Myosin-Light-Chain Phosphatase; D020742:rhoA GTP-Binding Protein