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Distribution of K ATP channel among the different fiber types in skeletal muscle.
Author(s) -
Banas Krystyna,
Renaud JeanMarc
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.961.7
Subject(s) - chemistry , myosin , medicine , kir6.2 , endocrinology , protein subunit , gene isoform , skeletal muscle , soleus muscle , fiber , biophysics , biochemistry , biology , gene , organic chemistry
The ATP‐sensitive K + channel (K ATP channel) is essential in preventing contractile dysfunctions during exercise and fatigue in skeletal muscle (Cifelli et al. 2007. J. Physiol. 582:843). The extent of the contractile dysfunctions varies in the order of FDB = EDL ≫ soleus. Our studies and others have shown that, in mouse, FDB is composed primarily of type IIA and IIX fibers, the EDL has primarily IIB and IIX while soleus is composed of I and IIA. The objective of this study was to test the hypothesis that the protein content for the K ATP channel is in the order of I < IIA ≪ IIB = IIX. Fiber types were identified using specific antibodies for each of the four myosin isoforms while the KATP channel was quantify using an antibody against the Kir6.2 subunit, which forms the pore of the channel. The data showed large Kir6.2 protein content in type IIA fibers of FDB and soleus, while very low levels were found in these same fibers in EDL. Type IIB (EDL only) and type IIX fibers (EDL & FDB) contained large amount of Kir6.2, while type I (FDB and soleus) had the lowest content. It is concluded that the expression of the Kir6.2 subunit of the KATP channel not only vary among fiber types, but also for type IIA fibers among different muscles. Research supported by an operating grant from the Natural Sciences and Engineering Council of Canada (NSERC).