The skeletal muscle atrophy genes for ubiquitin E3 ligases MuRf1 (muscle ring finger-1) and MAFbx (muscle atrophy F-box) (or atrogin- 1) are up-regulated under catabolic conditions where proteolysis. These ligases bind to and mediate ubiquitination of myofibrillar proteins for subsequent degradation during muscle atrophy and are considered as sensitive markers of muscle protein degradation by the Ub-proteasome system. Recombinant GST-MuRF1 is competent for both auto-ubiquitination and ubiquitination of substrate proteins, such as troponin I, in vitro.
Recombinant protein expressed with N-terminal GST-tag.