Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
21
|
| pubmed:dateCreated |
1994-6-29
|
| pubmed:databankReference | |
| pubmed:abstractText |
Phosphorylation of Ser residues in the NH2-terminal extension unique to cardiac troponin I (cTnI) is known to occur through protein kinase A and to alter myofilament Ca2+ activation (Robertson, S. P., Johnson, J. D., Holroyde, M. J., Kranias, E. G., Potter, J. D., and Solaro, R. J. (1982) J. Biol. Chem. 257, 260-263). Yet, how the NH2-terminal extension may itself affect thin filament Ca2+ signaling is unknown. To approach this question we have used molecular cloning, mutagenesis, and bacterial synthesis of a full-length cTnI and a truncated mutant (cTnI/NH2) missing the 32 amino acids. Using reconstituted preparations we could show no differences between cTnI and cTnI/NH2 either in inhibition of actomyosin ATPase activity, in Ca(2+)-reversible inhibitory activity, or in the relation between pCa and Ca2+ binding to the regulatory site of cTnC at either pH 7.0 or 6.5. There were also no significant differences at either pH in the pCa-MgATPase activity relation of myofibrils into which the various species of TnI has been exchanged. Our results indicate: 1) that phosphorylation most likely induces a new state of TnI activity rather than altering an intrinsic effect of the NH2-terminal peptide on Ca2+ activation; and 2) that domains outside the NH2-terminal extension are important with regard to differences in effects of acidic pH on Ca2+ activation on cardiac and skeletal myofilaments.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
May
|
| pubmed:issn |
0021-9258
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
27
|
| pubmed:volume |
269
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
15210-6
|
| pubmed:dateRevised |
2011-11-17
|
| pubmed:meshHeading |
pubmed-meshheading:8195157-Actin Cytoskeleton,
pubmed-meshheading:8195157-Amino Acid Sequence,
pubmed-meshheading:8195157-Animals,
pubmed-meshheading:8195157-Base Sequence,
pubmed-meshheading:8195157-Cloning, Molecular,
pubmed-meshheading:8195157-DNA, Complementary,
pubmed-meshheading:8195157-Escherichia coli,
pubmed-meshheading:8195157-Hydrogen-Ion Concentration,
pubmed-meshheading:8195157-Mice,
pubmed-meshheading:8195157-Molecular Sequence Data,
pubmed-meshheading:8195157-Mutagenesis,
pubmed-meshheading:8195157-Myocardium,
pubmed-meshheading:8195157-Peptide Fragments,
pubmed-meshheading:8195157-Phosphorylation,
pubmed-meshheading:8195157-Sequence Deletion,
pubmed-meshheading:8195157-Spectrometry, Fluorescence,
pubmed-meshheading:8195157-Troponin,
pubmed-meshheading:8195157-Troponin I
|
| pubmed:year |
1994
|
| pubmed:articleTitle |
Mutagenesis of cardiac troponin I. Role of the unique NH2-terminal peptide in myofilament activation.
|
| pubmed:affiliation |
Department of Physiology and Biophysics, College of Medicine, University of Illinois, Chicago 60612-7342.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
|