Contractile activity in smooth muscle cells is regulated by phosphorylation-dephosphorylation of the 20,000-Da light chain of myosin. In an attempt to better understand the localization in muscle of the enzymes which catalyze the phosphorylation-dephosphorylation process, we measured the binding constants of turkey gizzard smooth muscle myosin light chain (MLC) kinase and smooth muscle phosphat...

Dictyostelium myosin is composed of two heavy chains and two pairs of light chains in a 1:1:1 stoichiometry. Myosin purified from amoebae grown in medium containing [32P]phosphate had two of the subunits labeled (0.2-0.3 mol of phosphate per mol of 210,000-dalton heavy chains and approximately 0.1 mol of phosphate per mol of 18,000-dalton light chain). Kinase activities specific for the 210,000...

Intracellular calcium concentration ([Ca]i)-dependent activation of myosin light chain kinase and its phosphorylation of the 20-kd light chain of myosin is generally considered the primary mechanism responsible for regulation of contractile force in arterial smooth muscle. However, recent data suggest that the relation between [Ca], and myosin light chain phosphorylation is variable and depends...

The inhibition of myosin phosphatase evokes smooth muscle contraction in the absence of Ca(2+), yet the underlying mechanisms are not understood. To this end, we have cloned smooth muscle zipper-interacting protein (ZIP) kinase cDNA. ZIP kinase is present in various smooth muscle tissues including arteries. Triton X-100 skinning did not diminish ZIP kinase content, suggesting that ZIP kinase as...

Intracellular calcium concentration ([Ca2+]i)-dependent activation of myosin light chain kinase and its phosphorylation of the 20-kd light chain of myosin is generally considered the primary mechanism responsible for regulation of contractile force in arterial smooth muscle. However, recent data suggest that the relation between [Ca2+]i and myosin light chain phosphorylation is variable and dep...

Systematically synthesized derivatives of ML-9, 1-(5-chloronaphthalenesulfonyl)-1H-hexahydro-1,4-diazepine, were found to inhibit both Ca2+-calmodulin-dependent and -independent smooth muscle myosin light chain kinases with a similar concentration dependence, and their inhibitions were of the competitive type with respect to ATP. Moreover, ML-9 as well as ATP or ADP exhibited an effective prote...

The inhibition of myosin phosphatase evokes smooth muscle contraction in the absence of Ca, yet the underlying mechanisms are not understood. To this end, we have cloned smooth muscle zipper-interacting protein (ZIP) kinase cDNA. ZIP kinase is present in various smooth muscle tissues including arteries. Triton X-100 skinning did not diminish ZIP kinase content, suggesting that ZIP kinase associ...

The aim of this study was to examine the changes in muscle proteome of the rainbow trout fed dietary β-glucan. The experimental diets contained 0 (control), 0.1% and 0.2% β-1,3/1,6 yeast glucan. First, feeding larvae were fed to apparent satiation nine times per day with their respective diets over two months. The percentage of body weight gain and feed efficiency of fish fed 0.2% diet was sign...