Open AccessA New Myofibrillar Protein Characteristic of Type I Human Skeletal Muscle Fibres
Author(s) -
HEIZMANN Claus W.,
CELIO Marco R.,
BILLETER Rudolf,
REIST Ursula,
MORET MariaLuisa,
ARNOLD Eva M.
Publication year - 1983
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1983.tb07415.x
Subject(s) - myofibril , myosin , skeletal muscle , actin , protein subunit , chemistry , microbiology and biotechnology , biochemistry , biology , anatomy , gene
Analysis of a single human type I (slow‐twitch) skeletal muscle fibres by two‐dimensional gel electrophoresis shows that they contain a specific protein of subunit M, 34 × 10 3 and PI 6.0,6.1 and 6.2 (three spots) which is absent from type IIA and IIB muscle fibres. This type I protein is located in the I‐band of isolated myofibrils as demonstrated by the indirect immunofluorescence using specific antisera against the denatured form of type I protein. Type I protein could only be extracted from myofibrils with high salt solutions (0.6 ‐ 1 M KCl), conditions which also coextract actin and myosin, demonstrating its firm attachment. Rat and cat type I muscle fibres as well as the slow‐tonic fibres from chicken anterior latissimus dorsi also contained a protein homologous to the human type I protein. The human type I protein was found to be different from the known regulatory and contractile muscle proteins by electrophoretic and immunological criteria, and may therefore be a new myofibrillar protein in type I muscle fibres.