Open AccessUBE2B is implicated in myofibrillar protein loss in catabolic C2C12 myotubes
Author(s) -
Polge Cécile,
Leulmi Roza,
Jarzaguet Marianne,
Claustre Agnes,
Combaret Lydie,
Béchet Daniel,
Heng AnneElisabeth,
Attaix Didier,
Taillandier Daniel
Publication year - 2016
Publication title -
journal of cachexia, sarcopenia and muscle
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.803
H-Index - 66
eISSN - 2190-6009
pISSN - 2190-5991
DOI - 10.1002/jcsm.12060
Subject(s) - myogenesis , catabolism , proteasome , c2c12 , ubiquitin , skeletal muscle , anabolism , ubiquitin ligase , protein degradation , biochemistry , chemistry , myofibril , myocyte , microbiology and biotechnology , enzyme , biology , endocrinology , gene
Background Skeletal muscle protein loss is an adaptive response to various patho‐physiological situations, and the ubiquitin proteasome system (UPS) is responsible for the degradation of the bulk of muscle proteins. The role of E2 ubiquitin‐conjugating enzymes is still poorly understood in skeletal muscle. Methods We screened for E2s expression levels in C2C12 myotubes submitted to the catabolic glucocorticoid dexamethasone (Dex). Results One micromolar Dex induced an accumulation of proteasome substrates (polyUb conjugates) and an overexpression of the muscle‐specific E3 ligase MuRF1 and of six E2 enzymes, UBE2A, UBE2B, UBE2D1, UBE2D2, UBE2G1, and UBE2J1. However, only MuRF1 and UBE2B were sensitive to mild catabolic conditions (0.16 μM Dex). UBE2B knockdown induced a sharp decrease of total (−18%) and K48 (−28%) Ub conjugates, that is, proteasome substrates, indicating an important role of UBE2B in the overall protein breakdown in catabolic myotubes. Conclusions Interestingly, these results indicate an important role of UBE2B on muscle protein homeostasis during catabolic conditions.