Tripartite motif-containing protein 34 (TRIM34), also known as RING finger protein 21 (RNF21) or interferon-responsive finger protein 1 (IFP1), is a 488 amino acid member of the TRIM family, also known as the RING-B-box coiled-coil (RBCC) family. Members of the RBCC family have an N-terminal RING finger, followed by one or two zinc-binding domains (B-box domains), a leucine coiled-coil region and a variable C-terminal domain. Three isoforms of TRIM34 exist as a result of alternative splicing events. Isoform 1, the most abundant isoform, is highly expressed in placenta, spleen, colon and peripheral blood leukocytes. Studies have shown that Interferon (IFN) stimulation leads to an upregulation of TRIM34. These findings suggest that TRIM34 maybe a downstream effector that mediates IFN activities.