Title
Smooth muscle myosin phosphorylated at single head shows sustained mechanical activity
UMMS Affiliation
Graduate School of Biomedical Sciences; Department of Physiology
Publication Date
2008-04-15
Document Type
Article
Disciplines
Life Sciences | Medicine and Health Sciences
Abstract
Smooth muscle contraction is regulated by the phosphorylation of myosin. It is well known that tonic smooth muscles can maintain force with low energy consumption (latch state); however, the molecular mechanism underlying this phenomenon is unresolved. Here we show that single-head phosphorylated smooth myosin (SHPMII) exhibits fast ( approximately 24 s(-1)) and slow prolonged ( approximately 1 s(-1)) actin interactions, whereas double-head phosphorylated myosin (DHPMII) predominantly exhibits the fast ( approximately 29 s(-1)) interaction, suggesting that the phosphorylated head of SHPMII is mechanically as active as that of DHPMII. Both the fast and the slow actin interactions of SHPMII support the positive net mechanical displacement of actin. The actin translocating velocity of SHPMII was much slower than that of DHPMII, which is consistent with the slow actin interaction of SHPMII. We propose that the "latch state" can be explained by the motor characteristics of SHPMII that is present during the sustained phase of contraction.
DOI of Published Version
10.1074/jbc.M71059720
Source
J Biol Chem. 2008 Jun 6;283(23):15611-8. Epub 2008 Apr 11. Link to article on publisher's site
Journal/Book/Conference Title
The Journal of biological chemistry
Related Resources
PubMed ID
18408003
Repository Citation
Tanaka H, Homma K, White HD, Yanagida T, Ikebe M. (2008). Smooth muscle myosin phosphorylated at single head shows sustained mechanical activity. GSBS Student Publications. https://doi.org/10.1074/jbc.M71059720. Retrieved from https://escholarship.umassmed.edu/gsbs_sp/1477