Modified RING finger, HC subclass (C3HC3D-type), found in Roquin-2
Roquin-2, also known as membrane-associated nucleic acid-binding protein (MNAB), RING finger and CCCH-type zinc finger domain-containing protein 2 (RC3H2), or RING finger protein 164 (RNF164), is an E3 ubiquitin ligase that is localized to the cytoplasm and upon stress, is concentrated in stress granules. It is required for reactive oxygen species (ROS)-induced ubiquitination and degradation of apoptosis signal-regulating kinase 1 (ASK1, also known as MAP3K5). Roquin-2 interacts with the 3'UTR of tumor necrosis factor receptor superfamily member 4 (TNFRSF4) and tumor-necrosis factor-alpha (TNFalpha), and modulates immune responses. Moreover, Roquin-2 shares functions with its paralog Roquin-1 in the repression of mRNAs controlling T follicular helper cells and systemic inflammation. Roquin-2 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, a coiled-coil (CC1), and a CCCH-type zinc finger that is involved in RNA recognition.
Comment:based on the structure of Mus musculus Roquin with bound Zn2+ ions through its modified RING-HC finger
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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",