RING finger, HC subclass, found in Saccharomyces cerevisiae POB3/SPT16 histone-associated protein 1 (ScPSH1), Arabidopsis thaliana Protein KEEP ON GOING (AtKEG) and similar proteins
ScPSH1 is a Cse4-specific E3 ubiquitin ligase that interacts with the kinetochore protein Pat1 and targets the degradation of budding yeast centromeric histone H3 variant, CENP-ACse4, which is essential for faithful chromosome segregation. ScPSH1 contains a C3HC4-type RING-HC finger and a DNA directed RNA polymerase domain. AtKEG is an E3 ubiquitin ligase essential for Arabidopsis growth and development. It maintains low levels of ABSCISIC ACID-INSENSITIVE5 (ABI5) in the absence of stress and thus functions as a negative regulator of abscisic acid (ABA) signaling. AtKEG is a multidomain protein that includes a C3HC4-type RING-HC finger, a kinase domain, ankyrin repeats, and 12 HERC2-like (for HECT and RCC1-like) repeats.