InterPro domain: IPR045103

This entry represents a group of RING membrane-anchor proteins, including RNF5/RNF185 from humans and AtRMA1/AtRMA2/AtRMA3 from Arabidopsis. They contain a RING finger motif and a C-terminal membrane-anchoring domain. RNF5 and RNF185 are E3 ubiquitin-protein ligases [ 1 , 2 ].

AtRMA1, AtRMA2, and AtRMA3, are endoplasmic reticulum (ER)-localized Arabidopsis homologues of human outer membrane of the ER-anchor E3 ubiquitin-protein ligase, RING finger protein 5 (RNF5) [ 3 ]. AtRMAs possess E3 ubiquitin ligase activity, and may play a role in the growth and development of Arabidopsis. The AtRMA1 and AtRMA3 genes are predominantly expressed in major tissues, such as cotyledons, leaves, shoot-root junction, roots, and anthers, while AtRMA2 expression is restricted to the root tips and leaf hydathodes. AtRma1 probably functions with the Ubc4/5 subfamily of E2. AtRMA2 is likely involved in the cellular regulation of ABP1 expression levels through interacting with auxin binding protein 1 (ABP1). AtRMA proteins contain an N-terminal C3HC4-type RING-HC finger and a trans-membrane-anchoring domain in their extreme C-terminal region [ 4 ].

1. RNF5, a RING finger protein that regulates cell motility by targeting paxillin ubiquitination and altered localization. Mol Cell Biol 23, 5331-45
2. RNF185 is a novel E3 ligase of endoplasmic reticulum-associated degradation (ERAD) that targets cystic fibrosis transmembrane conductance regulator (CFTR). J Biol Chem 288, 31177-91
3. Rma1, a novel type of RING finger protein conserved from Arabidopsis to human, is a membrane-bound ubiquitin ligase. J Cell Sci 114, 1949-57
4. Functional analysis of the RING-type ubiquitin ligase family of Arabidopsis. Plant Physiol. 137, 13-30