Smooth muscle myosin phosphorylated at single head shows sustained mechanical activity
Document Type
Journal ArticlePublication Date
2008-04-15Keywords
Actins; Animals; Chickens; Muscle Contraction; Muscle, Smooth; Myosins; Phosphorylation; Rabbits; TurkeysLife Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
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.Source
J Biol Chem. 2008 Jun 6;283(23):15611-8. Epub 2008 Apr 11. Link to article on publisher's siteDOI
10.1074/jbc.M71059720Permanent Link to this Item
http://hdl.handle.net/20.500.14038/32926PubMed ID
18408003Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1074/jbc.M71059720