Linked Life Data

11896035

Source:http://linkedlifedata.com/resource/pubmed/id/11896035

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2002-3-15
pubmed:abstractText
The role of phosphorylation of the myosin regulatory light chains (RLC) is well established in smooth muscle contraction, but in striated (skeletal and cardiac) muscle its role is still controversial. We have studied the effects of RLC phosphorylation in reconstituted myosin and in skinned skeletal muscle fibers where Ca2+ sensitivity and the kinetics of steady-state force development were measured. Skeletal muscle myosin reconstituted with phosphorylated RLC produced a much higher Ca2+ sensitivity of thin filament-regulated ATPase activity than nonphosphorylated RLC (change in -log of the Ca2+ concentration producing half-maximal activation = approximately 0.25). The same was true for the Ca2+ sensitivity of force in skinned skeletal muscle fibers, which increased on reconstitution of the fibers with the phosphorylated RLC. In addition, we have shown that the level of endogenous RLC phosphorylation is a crucial determinant of the Ca2+ sensitivity of force development. Studies of the effects of RLC phosphorylation on the kinetics of force activation with the caged Ca2+, DM-nitrophen, showed a slight increase in the rates of force development with low statistical significance. However, an increase from 69 to 84% of the initial steady-state force was observed when nonphosphorylated RLC-reconstituted fibers were subsequently phosphorylated with exogenous myosin light chain kinase. In conclusion, our results suggest that, although Ca2+ binding to the troponin-tropomyosin complex is the primary regulator of skeletal muscle contraction, RLC play an important modulatory role in this process.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
8750-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
92
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1661-70
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Phosphorylation of the regulatory light chains of myosin affects Ca2+ sensitivity of skeletal muscle contraction.
pubmed:affiliation
Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, Florida 33136, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't