Ring Finger Protein 39 (RNF39)

RING finger protein 39 lies within the major histocompatibility complex class I region on chromosome 6. Studies of a similar rat protein suggest that this gene encodes a protein that plays a role in an early phase of synaptic plasticity. Alternative splicing results in three transcript variants encoding different isoforms.The deduced proteins have 421, 355, and 257 amino acids, respectively. HZFW1 and HZFW2 contain both the N-terminal RING finger C3HC4 motif and the C-terminal B30-2-like domain, while HZFW3 lacks the B30-2-like motif. Human testis expressed all 3 variants. The deduced translation start site of HZFW1 differs from that of Lirf in that HZFW1 has an extra N-terminal stretch; however, both proteins retain the N-terminal RING finger motif. Fluorescence-tagged Lirf protein localized to the cytoplasm of COS-7 cells.