Journal article
Characterizations of myosin essential light chain's N-terminal truncation mutant Delta 43 in transgenic mouse papillary muscles by using tension transients in response to sinusoidal length alterations
Journal of muscle research and cell motility, Vol.34(2), pp.93-105
05/01/2013
DOI: 10.1007/s10974-013-9337-x
PMCID: PMC3656599
PMID: 23397074
Abstract
Cross-bridge kinetics were studied at 20 A degrees C in cardiac muscle strips from transgenic (Tg) mice expressing N-terminal 43 amino acid truncation mutation (Delta 43) of myosin essential light chain (ELC), and the results were compared to those from Tg-wild type (WT) mice. Sinusoidal length changes were applied to activated skinned papillary muscle strips to induce tension transients, from which two exponential processes were deduced to characterize the cross-bridge kinetics. Their two rate constants were studied as functions of ATP, phosphate (Pi), ADP, and Ca2+ concentrations to characterize elementary steps of the cross-bridge cycle consisting of six states. Our results demonstrate for the first time that the cross-bridge kinetics of Delta 43 are accelerated owing to an acceleration of the rate constant k (2) of the cross-bridge detachment step, and that the number of strongly attached cross-bridges are decreased because of a reduction of the equilibrium constant K (4) of the force generation step. The isometric tension and stiffness of Delta 43 are diminished compared to WT, but the force per cross-bridge is not changed. Stiffness measurement during rigor induction demonstrates a reduction in the stiffness in Delta 43, indicating that the N-terminal extension of ELC forms an extra linkage between the myosin cross-bridge and actin. The tension-pCa study demonstrates that there is no Ca2+ sensitivity change with Delta 43, but the cooperativity is diminished. These results demonstrate the importance of the N-terminal extension of ELC in maintaining the myosin motor function during force generation and optimal cardiac performance.
Details
- Title: Subtitle
- Characterizations of myosin essential light chain's N-terminal truncation mutant Delta 43 in transgenic mouse papillary muscles by using tension transients in response to sinusoidal length alterations
- Creators
- Li Wang - University of IowaPriya Muthu - University of MiamiDanuta Szczesna-Cordary - University of MiamiMasataka Kawai - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of muscle research and cell motility, Vol.34(2), pp.93-105
- DOI
- 10.1007/s10974-013-9337-x
- PMID
- 23397074
- PMCID
- PMC3656599
- NLM abbreviation
- J Muscle Res Cell Motil
- ISSN
- 0142-4319
- eISSN
- 1573-2657
- Publisher
- Springer Nature
- Number of pages
- 13
- Grant note
- R01HL070041 / NATIONAL HEART, LUNG, AND BLOOD INSTITUTE; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI) HL070041; HL108343; HL071778; HL090786 / National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA 10POST3420009 / American Heart Association
- Language
- English
- Date published
- 05/01/2013
- Academic Unit
- Anatomy and Cell Biology; Internal Medicine
- Record Identifier
- 9984284337702771
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