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Mapping of O ‐linked β ‐ N ‐acetylglucosamine modification sites in key contractile proteins of rat skeletal muscle
Author(s) -
Hédou Julie,
Bastide Bruno,
Page Adeline,
Michalski JeanClaude,
Morelle Willy
Publication year - 2009
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200800617
Subject(s) - tropomyosin , myosin , actin , skeletal muscle , heavy meromyosin , threonine , n acetylglucosamine , biochemistry , chemistry , microbiology and biotechnology , serine , biology , phosphorylation , anatomy , enzyme
O ‐linked β‐ N ‐acetylglucosamine ( O ‐GlcNAc) is a widespread modification of serine/threonine residues of nucleocytoplasmic proteins. Recently, several key contractile proteins in rat skeletal muscle ( i.e ., myosin heavy and light chains and actin) were identified as O ‐GlcNAc modified. Moreover, it was demonstrated that O ‐GlcNAc moieties involved in contractile protein interactions could modulate Ca 2+ activation parameters of contraction. In order to better understand how O ‐GlcNAc can modulate the contractile activity of muscle fibers, we decided to identify the sites of O ‐GlcNAc modification in purified contractile protein homogenates. Using an MS‐based method that relies on mild β‐elimination followed by Michael addition of DTT (BEMAD), we determined the localization of one O ‐GlcNAc site in the subdomain four of actin and four O ‐GlcNAc sites in the light meromyosin region of myosin heavy chains (MHC). According to previous reports concerning the role of these regions, our data suggest that O ‐GlcNAc sites might modulate the actin–tropomyosin interaction, and be involved in MHC polymerization or interactions between MHC and other contractile proteins. Thus, the results suggest that this PTM might be involved in protein–protein interactions but could also modulate the contractile properties of skeletal muscle.