E3 ubiquitin ligase that plays a role in the maintenance of muscle cell boundaries and muscle dense bodies, which establish the adhesion sites of the muscle cells to the extracellular matrix (PubMed:15210732). Ubiquitinates the LIM domain protein unc-95, thereby regulating its dislocalization from muscle dense bodies and weakening the link between the muscle cells and the hypodermis (PubMed:20385102, PubMed:15210732). Regulation of unc-95 dissociation from muscle dense bodies by ubiquitination plays an important role in ecdysis during molting (PubMed:20385102). Plays a role in the cessation of distal tip cell migration at the end of larval morphogenesis (PubMed:22285439). Acts as a negative regulator of autophagy (PubMed:23093945). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Colocalizes with deb-1/vinculin in muscle dense bodies. Expressed in body wall muscles. Expressed in larval stages L1, L2 and L3 and in adult animals with high expression during molting (at protein level). RNAi-mediated knockdown leads to disorganized muscle dense bodies and abnormal muscle-muscle cell boundaries. Accumulation of unc-95 in the muscle cell bodies. Belongs to the RNF5 family.