RING-CH finger, H2 subclass (C4HC3-type), found in membrane-associated RING-CH7 (MARCH7)
MARCH7, also known as membrane-associated RING finger protein 7, membrane-associated RING-CH protein VII (MARCH-VII), RING finger protein 177 (RNF177), or axotrophin, is a ubiquitin E3 ligase expressed in multiple types of cells and tissues, including stem cells and precursor cells, and is predominantly localized on the plasma membrane and cytoplasm. MARCH7 is involved in T cell proliferation and neuronal development. It also participates in the regulation of cytoskeleton re-organization, cellular migration and invasion, cell proliferation, and tumorigenesis in ovarian carcinoma cells. Moreover, MARCH7 modulates nuclear factor kappaB (NF-kappaB) and Wnt/beta-catenin pathways. It has been identified as an authentic target of miR-101. Furthermore, it ubiquitinates tau protein in vitro, impairing microtubule binding. Unlike other MARCH proteins, MARCH7 is predicted to have no transmembrane spanning region. It harbors a C4HC3-type RING-CH finger, also known as vRING or RINGv, a variant of C3H2C3-type RING-H2 finger, that is responsible for its E3 activity.
Comment:based on the structure of human MARCH8 with bound Zn2+ ions through its RING-CH finger
Comment:RING-CH finger (C4HC3-type)
Comment:A RING finger typically binds two zinc atoms, with its Cys and/or His side chains in a unique "cross-brace" arrangement.
Comment:The RING fingers found in MARCH proteins have an unusual arrangement of zinc-coordinating residues: The conserved helix complete with tryptophan at the C-terminal end is present but the cysteines and histidines are arranged in the sequence as C4HC3-type, rather than the typical C3H2C3-type in RING-H2 finger.
Jiyao W et al.(2023). "The conserved domain database in 2023.",