second Tudor domain found in Tudor domain-containing protein 4 (TDRD4) and similar proteins
TDRD4, also called RING finger protein 17 (RNF17), is a component of the mammalian germ cell nuage and is essential for spermiogenesis. It seems to be involved in the regulation of transcriptional activity of MYC. In vitro, TDRD4 inhibits the DNA-binding activity of Mad-MAX heterodimers. It can recruit Mad transcriptional repressors (MXD1, MXD3, MXD4 and MXI1) to the cytoplasm. TDRD4 also acts as a potential cancer/testis antigen in liver cancer. TDRD4 contains a RING finger and five Tudor domains. This model corresponds to the second one. The Tudor domain binds to proteins with dimethylated arginine or lysine residues, and may also bind methylated histone tails to facilitate protein-protein interactions.