RING finger, HC subclass, found in tripartite motif-containing proteins TRIM60, TRIM61 and similar proteins
TRIM60 and TRIM61 are two closely related tripartite motif-containing proteins. TRIM60, also known as RING finger protein 129 (RNF129) or RING finger protein 33 (RNF33), is a cytoplasmic protein expressed in the testis. It may play an important role in the spermatogenesis process, the development of the preimplantation embryo, and in testicular functions. RNF33 interacts with the cytoplasmic kinesin motor proteins KIF3A and KIF3B suggesting possible contribution to cargo movement along the microtubule in the expressed sites. It is also involved in spermatogenesis in Sertoli cells under the regulation of nuclear factor-kappaB (NF-kappaB). TRIM60 belongs the C-IV subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. In contrast to TRIM60, TRIM61 belongs to the C-V subclass of TRIM family that contains RBCC domains only. Its biological function remains unclear.