Modified RING finger, HC subclass (C3HC3D-type), found in ligand of numb protein X 2 (LNX2)
LNX2, also known as numb-binding protein 2, or PDZ domain-containing RING finger protein 1 (PDZRN1), is a PDZ domain-containing RING-type E3 ubiquitin ligase responsible for the ubiquitination and degradation of Numb, a component of the Notch signaling pathway that functions in the specification of cell fates during development and is known to control cell numbers during neurogenesis in vertebrates. It interacts with contactin-associated protein 4 (Caspr4, also known as CNTNAP4) in a PDZ domain-dependent manner, which modulates the proliferation and neuronal differentiation of neural progenitor cells (NPCs). LNX2 contains an N-terminal modified C3HC3D-type RING-HC finger, a NPAF motif for Numb/ Numblike-LNX interaction, and four PDZ domains necessary for the binding of substrates, including ErbB2, RhoC, the presynaptic protein CAST, the melanoma/cancer-testis antigen MAGEB18 and several proteins associated with cell junctions, such as JAM4 and the Coxsackievirus and adenovirus receptor (CAR).
Comment:consensus of the typical C3HC4-type RING-HC finger: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",