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Muscle specific Ring finger‐1 (MuRF‐1) siRNA in C2C12 cells leads to an increase in Troponin I protein
Author(s) -
Schaefer Jean,
Salter Eben,
Oleynek Joseph,
Loria Paula
Publication year - 2006
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.20.4.a808-d
Subject(s) - myogenesis , myocyte , skeletal muscle , ubiquitin ligase , ubiquitin , biology , troponin , sarcomere , muscle atrophy , c2c12 , troponin i , microbiology and biotechnology , medicine , endocrinology , biochemistry , myocardial infarction , gene
We have previously shown that the E3 ubiquitin ligase, MuRF‐1, is elevated in animal models of muscle atrophy, providing evidence for the involvement of MuRF‐1 in divergent models of skeletal muscle wasting. MuRF‐1 knockout mice show a resistance to denervation‐induced atrophy (Bodine et al. 2001), further implicating MuRF‐1 activity in the regulation of muscle wasting. Our laboratory is investigating the molecular pathways associated with MuRF‐1 action in skeletal muscle. Here we show the effects of MuRF‐1 siRNA on Troponin I protein levels in C2C12 cells, a mouse skeletal muscle cell line. C2C12 cells express muscle specific proteins and can be differentiated from myoblasts to myotubes by starving the cells in media with 2% horse serum in place of fetal bovine serum. When C2C12 myoblasts were transfected with MuRF‐1 siRNA duplexes (Dharmacon) and allowed to differentiate to myotubes, Troponin I protein levels increased relative to other muscle markers. MuRF‐1 overexpression caused a reciprocal decrease in Troponin I levels. These data are consistent with recent reports that cardiac troponin I is a direct ubiquitination target of MuRF‐1 (Kedar et al. 2004). Current work is focusing on determining whether direct ubiquitination of Troponin I is related to MuRF‐1’s role in muscle catabolism.