Requirement of the two‐headed structure for the phosphorylation dependent regulation of smooth muscle myosin

FEBS Letters

Matsu-ura, Motoi¹  Ikebe, Mitsuo¹ 

[1] Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4970, USA

关键词: Myosin;    Smooth muscle;    Phosphorylation;    Mg2+-ATPase activity;    Baculovirus expression;    HMM;    heavy meromyosin;    S-1;    myosin subfragment 1;    S-2;    myosin subfragment 2;    DTT;    dithiothreitol;    SDS-PAGE;    sodium dodecylsulfate polyacrylamide gel electrophoresis;    PMSF;    phenylmethylsulfonyl fluoride;   

DOI  :  10.1016/0014-5793(95)00326-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

It is known for smooth muscle myosin that while acto-HMM ATPase activity is regulated by phosphorylation, acto-S-1 ATPase activity is not regulated. To clarify the heavy chain structure required for the regulation, smooth muscle myosin containing 7 different lengths of the S-2 portion were expressed in Sf9 insect cells using Baculovirus expression system. Myosin containing longer than 991 residues of heavy chain formed a stable two-headed structure while myosin with shorter than 944 residues of heavy chain formed a single-headed structure, indicating that the residues Gln⁹⁴⁵-Asp⁹⁹¹ are critical for the fomation of the two-headed structure. The actin activated ATPase activity of myosin mutants having a two-headed structure was activated by phosphorylation while that of myosin mutants that failed to form the two-headed structure was completely independent of phosphorylation. These results suggest that the two-headed structure is critical for the phosphorylation-dependent regulation.

【 授权许可】

Unknown