May regulate gene expression and protein turnover in muscle cells. Homooligomer and heterooligomer (Probable). Interacts with titin/TTN. Interacts with myosins. Interacts with SQSTM1 and NBR1. Probably interacts with TRIM63 and TRIM54 (By similarity). Nuclear under atrophic conditions and upon mechanical signals. Localizes to the sarcomeric M-band in cardiomyocytes. Colocalizes in part with microtubules.