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Dependence of cross-bridge kinetics on myosin light chain isoforms in rabbit and rat skeletal muscle fibres.
J Physiol. 2006 Feb 15; 571(Pt 1):231-42.JP

Abstract

Cross-bridge kinetics underlying stretch-induced force transients was studied in fibres with different myosin light chain (MLC) isoforms from skeletal muscles of rabbit and rat. The force transients were induced by stepwise stretches (< 0.3% of fibre length) applied on maximally Ca2+-activated skinned fibres. Fast fibre types IIB, IID (or IIX) and IIA and the slow fibre type I containing the myosin heavy chain isoforms MHC-IIb, MHC-IId (or MHC-IIx), MHC-IIa and MHC-I, respectively, were investigated. The MLC isoform content varied within fibre types. Fast fibre types contained the fast regulatory MLC isoform MLC2f and different proportions of the fast alkali MLC isoforms MLC1f and MLC3f. Type I fibres contained the slow regulatory MLC isoform MLC2s and the slow alkali MLC isoform MLC1s. Slow MLC isoforms were also present in several type IIA fibres. The kinetics of force transients differed by a factor of about 30 between fibre types (order from fastest to slowest kinetics: IIB > IID > IIA >> I). The kinetics of the force transients was not dependent on the relative content of MLC1f and MLC3f. Type IIA fibres containing fast and slow MLC isoforms were about 1.2 times slower than type IIA fibres containing only fast MLC isoforms. We conclude that while the cross-bridge kinetics is mainly determined by the MHC isoforms present, it is affected by fast and slow MLC isoforms but not by the relative content of MLC1f and MLC3f. Thus, the physiological role of fast and slow MLC isoforms in type IIA fibres is a fine-tuning of the cross-bridge kinetics.

Authors+Show Affiliations

Department of Cell Biology, University of Salzburg, Hellbrunnerstrasse 34, A-5020, Salzburg, Austria.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16357018

Citation

Andruchov, Oleg, et al. "Dependence of Cross-bridge Kinetics On Myosin Light Chain Isoforms in Rabbit and Rat Skeletal Muscle Fibres." The Journal of Physiology, vol. 571, no. Pt 1, 2006, pp. 231-42.
Andruchov O, Andruchova O, Wang Y, et al. Dependence of cross-bridge kinetics on myosin light chain isoforms in rabbit and rat skeletal muscle fibres. J Physiol. 2006;571(Pt 1):231-42.
Andruchov, O., Andruchova, O., Wang, Y., & Galler, S. (2006). Dependence of cross-bridge kinetics on myosin light chain isoforms in rabbit and rat skeletal muscle fibres. The Journal of Physiology, 571(Pt 1), 231-42.
Andruchov O, et al. Dependence of Cross-bridge Kinetics On Myosin Light Chain Isoforms in Rabbit and Rat Skeletal Muscle Fibres. J Physiol. 2006 Feb 15;571(Pt 1):231-42. PubMed PMID: 16357018.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dependence of cross-bridge kinetics on myosin light chain isoforms in rabbit and rat skeletal muscle fibres. AU - Andruchov,Oleg, AU - Andruchova,Olena, AU - Wang,Yishu, AU - Galler,Stefan, Y1 - 2005/12/15/ PY - 2005/12/17/pubmed PY - 2006/4/28/medline PY - 2005/12/17/entrez SP - 231 EP - 42 JF - The Journal of physiology JO - J Physiol VL - 571 IS - Pt 1 N2 - Cross-bridge kinetics underlying stretch-induced force transients was studied in fibres with different myosin light chain (MLC) isoforms from skeletal muscles of rabbit and rat. The force transients were induced by stepwise stretches (< 0.3% of fibre length) applied on maximally Ca2+-activated skinned fibres. Fast fibre types IIB, IID (or IIX) and IIA and the slow fibre type I containing the myosin heavy chain isoforms MHC-IIb, MHC-IId (or MHC-IIx), MHC-IIa and MHC-I, respectively, were investigated. The MLC isoform content varied within fibre types. Fast fibre types contained the fast regulatory MLC isoform MLC2f and different proportions of the fast alkali MLC isoforms MLC1f and MLC3f. Type I fibres contained the slow regulatory MLC isoform MLC2s and the slow alkali MLC isoform MLC1s. Slow MLC isoforms were also present in several type IIA fibres. The kinetics of force transients differed by a factor of about 30 between fibre types (order from fastest to slowest kinetics: IIB > IID > IIA >> I). The kinetics of the force transients was not dependent on the relative content of MLC1f and MLC3f. Type IIA fibres containing fast and slow MLC isoforms were about 1.2 times slower than type IIA fibres containing only fast MLC isoforms. We conclude that while the cross-bridge kinetics is mainly determined by the MHC isoforms present, it is affected by fast and slow MLC isoforms but not by the relative content of MLC1f and MLC3f. Thus, the physiological role of fast and slow MLC isoforms in type IIA fibres is a fine-tuning of the cross-bridge kinetics. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/16357018/Dependence_of_cross_bridge_kinetics_on_myosin_light_chain_isoforms_in_rabbit_and_rat_skeletal_muscle_fibres_ L2 - https://doi.org/10.1113/jphysiol.2005.099770 DB - PRIME DP - Unbound Medicine ER -