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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
43
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pubmed:dateCreated |
1996-12-16
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pubmed:abstractText |
The N-terminal region of skeletal myosin light chain-1 (MLC-1) binds to the C terminus of actin, yet the functional significance of this interaction is unclear. We studied a fragment (MLC-pep; residues 5-14) of the ventricular MLC-1. When added to rat cardiac myofibrils, 10 nM MLC-pep induced a supramaximal increase in the MgATPase activity at submaximal Ca2+ levels with no effect at low and maximal Ca2+ levels. A nonsense, scrambled sequence peptide had no effect at any pCa value. MLC-pep did not affect myosin KEDTA and CaATPase activities or actin-activated MgATPase activities in the absence or presence of tropomyosin. The MLC-pep did not alter the ability of troponin I to inhibit MgATPase activity. Moreover, when troponin I and troponin C were extracted from the myofibrils, the MLC-pep lost its ability to stimulate the ATPase rate. This effect was fully restored upon reconstitution of the extracted myofibrils with troponin I-troponin C complex. Thus, activation of MgATPase activity by the peptide required a full complement of thin filament regulatory proteins. Interestingly, the stimulatory effect occurred at a ratio of 4 peptides to 1 thin filament, suggesting that the peptide engages in a highly cooperative process that may involve activation of the entire thin filament.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
271
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
27039-43
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:8900193-Adenosine Triphosphatases,
pubmed-meshheading:8900193-Amino Acid Sequence,
pubmed-meshheading:8900193-Animals,
pubmed-meshheading:8900193-Cattle,
pubmed-meshheading:8900193-Enzyme Activation,
pubmed-meshheading:8900193-Heart Ventricles,
pubmed-meshheading:8900193-Male,
pubmed-meshheading:8900193-Molecular Sequence Data,
pubmed-meshheading:8900193-Muscle Proteins,
pubmed-meshheading:8900193-Myocardial Contraction,
pubmed-meshheading:8900193-Myosin Light Chains,
pubmed-meshheading:8900193-Peptide Fragments,
pubmed-meshheading:8900193-Rats,
pubmed-meshheading:8900193-Rats, Sprague-Dawley,
pubmed-meshheading:8900193-Ventricular Function
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pubmed:year |
1996
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pubmed:articleTitle |
An essential myosin light chain peptide induces supramaximal stimulation of cardiac myofibrillar ATPase activity.
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pubmed:affiliation |
Department of Physiology and Biophysics, College of Medicine, University of Illinois, Chicago, Illinois 60612-7342, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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