Linked Life Data

11964067

Source:http://linkedlifedata.com/resource/pubmed/id/11964067

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2002-4-19
pubmed:abstractText
Whether the two heads of skeletal muscle myosin work independently or cooperatively remains an open question in muscle biophysics. While individual myosin heads are sufficient for ATPase activity (Reisler (1980) J Mol Biol 138: 93-107) and force production (Harada et al. (1987) Nature 326: 805-808), it has also been reported that in situ, the two heads of a myosin molecule work cooperatively (Chaen et al. (1986) J Biol Chem 261(29): 13,632-13,636). To examine the role of cross-bridge cooperativity on isometric contraction and unloaded shortening we progressively inactivated myosin cross-bridges via titration with para-phenylenedimaleimide. The resting fiber ATPase was measured to provide an estimate of the fraction of active cross-bridges remaining during the titration. Isometric force and unloaded shortening velocity decline more rapidly than the resting ATPase as the titration proceeds. This is inconsistent with models for independent force generation and suggests cooperative action of myosin cross-bridges when muscle is isometrically contracting or shortening under zero load. However the degree of cooperativity depends on the type of muscle activity. While isometric force declines in a manner consistent with pair-wise cooperative action of myosin heads, unloaded shortening velocity declines more rapidly (greater cooperativity). Therefore, myosin cross-bridges in situ may be capable of at least two types of cooperative interactions, pair-wise cooperativity (when isometric) and another form of cooperativity that is sensitive to longer range interactions transmitted from other cross-bridges in the ensemble (during unloaded shortening).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0142-4319
pubmed:author
pubmed:issnType
Print
pubmed:volume
22
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
415-23
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Cross-bridge cooperativity during isometric contraction and unloaded shortening of skeletal muscle.
pubmed:affiliation
Department of Physiology, University of Minnesota Medical School, Minneapolis 55455, USA. barne014@tc.umn.edu
pubmed:publicationType
Journal Article, Comparative Study, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't