GTP/ggS‐Induced phosphorylation of myosin light chain kinase in smooth muscle

[摘要]

Phosphorylation of myosin light chain kinase by a Ca²⁺-dependent protein kinase increases the concentration of Ca²⁺/calmodulin required for half-maximal activation. The Ca²⁺ concentrations required for myosin light chain kinase phosphorylation in permeable smooth muscle are similar to those required for myosin light chain phosphorylation. Both GTPγS and carbachol increase the Ca²⁺ sensitivity of myosin light chain kinase phosphorylation as well as light chain phosphorylation. It is proposed that a similar G-protein mediated mechanism regulates the Ca²⁺-dependent phosphorylation of these two contractile proteins in smooth muscle.

[学科分类] 生物化学/生物物理

[关键词] Smooth muscle contraction;Myosin light chain;Myosin light chain kinase;GTPγS;Protein phosphatase;[Ca2*]i;free intracellular Ca2+ concentration;KN-62;1-[N-O-Bis(5-isoquinolinesulfonyl)-N+-methyl-l-tyrosyl]-4-phenylpiperazine;G-protein;guanine nucleotide-binding protein;PSS;physiological salt solution;PAGE;polyacrylamide gel electrophoresis;PMSF;phenylmethylsulfonyl fluoride;EDTA;ethylenediamine-tetraacetic acid;MOPS;3-[N-morpholino]propane-sulfonic acid;EGTA;ethyleneglycol-bis (β-aminoethylether)N;N;N';N';-tetraacetic acid;k cam;concentration of Ca2+/calmodulin required for half-maximal activation;PIPES;piperazine-N;N-bis[2-ethane-sulfonic acid]