Requirement of the two‐headed structure for the phosphorylation dependent regulation of smooth muscle myosin
- 24 April 1995
- journal article
- Published by Wiley in FEBS Letters
- Vol. 363 (3), 246-250
- https://doi.org/10.1016/0014-5793(95)00326-5
Abstract
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.Keywords
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