Linked Life Data

15961398

Source:http://linkedlifedata.com/resource/pubmed/id/15961398

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
2005-8-29
pubmed:abstractText
Human cardiac Troponin I (cTnI) is the first sarcomeric protein for which mutations have been associated with restrictive cardiomyopathy. To determine whether five mutations in cTnI (L144Q, R145W, A171T, K178E, and R192H) associated with restrictive cardiomyopathy were distinguishable from hypertrophic cardiomyopathy-causing mutations in cTnI, actomyosin ATPase activity and skinned fiber studies were carried out. All five mutations investigated showed an increase in the Ca2+ sensitivity of force development compared with wild-type cTnI. The two mutations with the worst clinical phenotype (K178E and R192H) both showed large increases in Ca2+ sensitivity (deltapCa50 = 0.47 and 0.36, respectively). Although at least one of these mutations is not in the known inhibitory regions of cTnI, all of the mutations investigated caused a decrease in the ability of cTnI to inhibit actomyosin ATPase activity. Mixtures of wild-type and mutant cTnI showed that cTnI mutants could be classified into three different groups: dominant (L144Q, A171T and R192H), equivalent (K178E), or weaker (R145W) than wild-type cTnI in actomyosin ATPase assays in the absence of Ca2+. Although most of the mutants were able to activate actomyosin ATPase similarly to wild-type cTnI, L144Q had significantly lower maximal ATPase activities than any of the other mutants or wild-type cTnI. Three mutants (L144Q, R145W, and K178E) were unable to fully relax contraction in the absence of Ca2+. The inability of the five cTnI mutations investigated to fully inhibit ATPase activity/force development and the generally larger increases in Ca2+ sensitivity than observed for most hypertrophic cardiomyopathy mutations would likely lead to severe diastolic dysfunction and may be the major physiological factors responsible for causing the restrictive cardiomyopathy phenotype in some of the genetically affected individuals.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
30909-15
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Mutations in human cardiac troponin I that are associated with restrictive cardiomyopathy affect basal ATPase activity and the calcium sensitivity of force development.
pubmed:affiliation
Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural