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Influence of fast and slow alkali myosin light chain isoforms on the kinetics of stretch-induced force transients of fast-twitch type IIA fibres of rat.
Pflugers Arch. 2008 Mar; 455(6):1165-72.PA

Abstract

This study contributes to understand the physiological role of slow myosin light chain isoforms in fast-twitch type IIA fibres of skeletal muscle. These isoforms are often attached to the myosin necks of rat type IIA fibres, whereby the slow alkali myosin light chain isoform MLC1s is much more frequent and abundant than the slow regulatory myosin light chain isoform MLC2s. In the present study, single-skinned rat type IIA fibres were maximally Ca(2+) activated and subjected to stepwise stretches for causing a perturbation of myosin head pulling cycles. From the time course of the resulting force transients, myosin head kinetics was deduced. Fibres containing MLC1s exhibited slower kinetics independently of the presence or absence of MLC2s. At the maximal MLC1s concentration of about 75%, the slowing was about 40%. The slowing effect of MLC1s is possibly due to differences in the myosin heavy chain binding sites of the fast and slow alkali MLC isoforms, which changes the rigidity of the myosin neck. Compared with the impact of myosin heavy chain isoforms in various fast-twitch fibre types, the influence of MLC1s on myosin head kinetics of type IIA fibres is much smaller. In conclusion, the physiological role of fast and slow MLC isoforms in type IIA fibres is a fine-tuning of the myosin head kinetics.

Authors+Show Affiliations

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

Pub Type(s)

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

Language

eng

PubMed ID

17960418

Citation

Andruchov, Oleg, and Stefan Galler. "Influence of Fast and Slow Alkali Myosin Light Chain Isoforms On the Kinetics of Stretch-induced Force Transients of Fast-twitch Type IIA Fibres of Rat." Pflugers Archiv : European Journal of Physiology, vol. 455, no. 6, 2008, pp. 1165-72.
Andruchov O, Galler S. Influence of fast and slow alkali myosin light chain isoforms on the kinetics of stretch-induced force transients of fast-twitch type IIA fibres of rat. Pflugers Arch. 2008;455(6):1165-72.
Andruchov, O., & Galler, S. (2008). Influence of fast and slow alkali myosin light chain isoforms on the kinetics of stretch-induced force transients of fast-twitch type IIA fibres of rat. Pflugers Archiv : European Journal of Physiology, 455(6), 1165-72.
Andruchov O, Galler S. Influence of Fast and Slow Alkali Myosin Light Chain Isoforms On the Kinetics of Stretch-induced Force Transients of Fast-twitch Type IIA Fibres of Rat. Pflugers Arch. 2008;455(6):1165-72. PubMed PMID: 17960418.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of fast and slow alkali myosin light chain isoforms on the kinetics of stretch-induced force transients of fast-twitch type IIA fibres of rat. AU - Andruchov,Oleg, AU - Galler,Stefan, Y1 - 2007/10/25/ PY - 2007/09/17/received PY - 2007/10/04/accepted PY - 2007/10/26/pubmed PY - 2008/7/1/medline PY - 2007/10/26/entrez SP - 1165 EP - 72 JF - Pflugers Archiv : European journal of physiology JO - Pflugers Arch VL - 455 IS - 6 N2 - This study contributes to understand the physiological role of slow myosin light chain isoforms in fast-twitch type IIA fibres of skeletal muscle. These isoforms are often attached to the myosin necks of rat type IIA fibres, whereby the slow alkali myosin light chain isoform MLC1s is much more frequent and abundant than the slow regulatory myosin light chain isoform MLC2s. In the present study, single-skinned rat type IIA fibres were maximally Ca(2+) activated and subjected to stepwise stretches for causing a perturbation of myosin head pulling cycles. From the time course of the resulting force transients, myosin head kinetics was deduced. Fibres containing MLC1s exhibited slower kinetics independently of the presence or absence of MLC2s. At the maximal MLC1s concentration of about 75%, the slowing was about 40%. The slowing effect of MLC1s is possibly due to differences in the myosin heavy chain binding sites of the fast and slow alkali MLC isoforms, which changes the rigidity of the myosin neck. Compared with the impact of myosin heavy chain isoforms in various fast-twitch fibre types, the influence of MLC1s on myosin head kinetics of type IIA fibres is much smaller. In conclusion, the physiological role of fast and slow MLC isoforms in type IIA fibres is a fine-tuning of the myosin head kinetics. SN - 0031-6768 UR - https://www.unboundmedicine.com/medline/citation/17960418/Influence_of_fast_and_slow_alkali_myosin_light_chain_isoforms_on_the_kinetics_of_stretch_induced_force_transients_of_fast_twitch_type_IIA_fibres_of_rat_ L2 - https://dx.doi.org/10.1007/s00424-007-0369-1 DB - PRIME DP - Unbound Medicine ER -