Linked Life Data

15331360

Source:http://linkedlifedata.com/resource/pubmed/id/15331360

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2004-11-19
pubmed:abstractText
It is generally recognized that ventricular myosin regulatory light chains (RLC) are approximately 40% phosphorylated under basal conditions, and there is little change in RLC phosphorylation with agonist stimulation of myocardium or altered stimulation frequency. To establish the functional consequences of basal RLC phosphorylation in the heart, we measured mechanical properties of rat skinned trabeculae in which approximately 7% or approximately 58% of total RLC was phosphorylated. The protocol for achieving approximately 7% phosphorylation of RLC involved isolating trabeculae in the presence of 2,3-butanedione monoxime (BDM) to dephosphorylate RLC from its baseline level. Subsequent phosphorylation to approximately 58% of total was achieved by incubating BDM-treated trabeculae in solution containing smooth muscle myosin light chain kinase, calmodulin, and Ca2+ (i.e., MLCK treatment). After MLCK treatment, Ca2+ sensitivity of force increased by 0.06 pCa units and maximum force increased by 5%. The rate constant of force development (ktr) increased as a function of Ca2+ concentration in the range between pCa 5.8 and pCa 4.5. When expressed versus pCa, the activation dependence of ktr appeared to be unaffected by MLCK treatment; however, when activation was expressed in terms of isometric force-generating capability (as a fraction of maximum), MLCK treatment slowed ktr at submaximal activations. These results suggest that basal phosphorylation of RLC plays a role in setting the kinetics of force development and Ca2+ sensitivity of force in cardiac muscle. Our results also argue that changes in RLC phosphorylation in the range examined here influence actin-myosin interaction kinetics differently in heart muscle than was previously reported for skeletal muscle.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0363-6135
pubmed:author
pubmed:issnType
Print
pubmed:volume
287
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H2712-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Basal myosin light chain phosphorylation is a determinant of Ca2+ sensitivity of force and activation dependence of the kinetics of myocardial force development.
pubmed:affiliation
Dept. of Physiology, Univ. of Wisconsin Medical School, 1300 University Ave., Madison, WI 53706, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't