RING finger, HC subclass, found in RING finger proteins RNF212, RNF212B and similar proteins
This subfamily includes RING finger protein RNF212, RNF212B, and their homologs. RNF212 is a dosage-sensitive regulator of crossing-over during mammalian meiosis. It plays a central role in designating crossover sites and coupling chromosome synapsis to the formation of crossover-specific recombination complexes. It also functions as an E3 ligase for small ubiquitin-related modifier (SUMO) modification. RNF212B shows high sequence similarity with RNF212, but its biological function remains unclear. Members of this subfamily contain an N-terminal C3HC4-type RING-HC finger. Also included are two homologs of RNF212, meiotic procrossover factors Zip3 and ZHP-3, which have been identified in Saccharomyces cerevisiae and Caenorhabditis elegans, respectively. Budding yeast Zip3 is a small ubiquitin-related modifier (SUMO) E3 ligase implicated in the SUMO pathway of post-translational modification. It sumoylates chromosome axis proteins, thus promoting synaptonemal complex polymerization. It also acts as an Smt3 E3 ligase. Zip3 includes a SUMO Interacting Motif (SIM) and a modified C3HCHC2-type RING-HC finger that are important for Zip3 in vitro E3 ligase activity and necessary for SC polymerization and correct sporulation. ZHP-3 acts at crossovers to couple meiotic recombination with synaptonemal complex disassembly and chiasma formation in Caenorhabditis elegans. It possesses a C3HC4-type RING-HC finger.
Comment:C3HC4-type RING-HC finger consensus motif: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, where 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.
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