Modified RING finger, HC subclass (C3HC3D-type), found in Roquin-1
Roquin-1, also known as RING finger and C3H zinc finger protein 1 (RC3H1), or RING finger protein 198 (RNF198), is a ubiquitously expressed RNA-binding protein essential for degradation of inflammation-related mRNAs and maintenance of immune homeostasis. It is localized in cytoplasmic granules and binds to the 3' untranslated region (3'UTR) of inducible costimulator (Icos) mRNA to post-transcriptionally repress its expression. Roquin-1 interacts with the 3'UTR of tumor necrosis factor receptor superfamily member 4 (TNFRSF4) and tumor-necrosis factor-alpha (TNFalpha), and post-transcriptionally regulates A20 mRNA and modulates the activity of the IKK/NF-kappaB pathway. Moreover, Roquin-1 shares functions with its paralog Roquin-2 in the repression of mRNAs controlling T follicular helper cells and systemic inflammation. Roquin-1 contains an N-terminal modified C3HC3D-type RING-HC finger with a potential E3 ubiquitin-ligase function, a highly conserved ROQ domain required for RNA binding and localization to stress granules, and a CCCH-type zinc finger that is involved in RNA recognition, typically contacting AU-rich elements. In addition, both N- and C-terminal to the ROQ domain are combined to form a HEPN (higher eukaryotes and prokaryotes nucleotide-binding) domain that is highly likely to function as an RNA-binding domain.
Conserved feature residue pattern:C C C H C C C [DE]
Evidence:
Structure:4TXA; Mus musculus Roquin binds two Zn2+ ions, contacts at 4A. - View structure with Cn3D
Comment:modified RING-HC finger (C3HC3D-type)
Comment:consensus of the typical C3HC4-type RING-HC finger: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, X is any amino acid and the number of X residues varies in different fingers.
Comment:A RING finger typically binds two zinc atoms, with its Cys and/or His side chains in a unique "cross-brace" arrangement.