RING finger family found sporadically in bacteria and archaea, and associated in gene neighborhoods with other components of the ubiquitin-based signaling and degradation system, including ubiquitin, the E1 and E2 proteins and the JAB-like metallopeptidase. The bacterial versions contain transmembrane helices.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.",