This domain is found in calcium-binding and coiled-coil domain 2/NDP25 (CALCOCO2/NDP25) found in Homo sapiens. CALCOCO2/NDP25 is an ubiquitin-binding autophagy receptor involved in the selective autophagic degradation of invading pathogens. This domain is a typical C2H2-type zinc finger which specifically recognizes mono-ubiquitin or poly-ubiquitin chain. The overall ubiquitin-binding mode utilizes the C-terminal alpha-helix to interact with the solvent-exposed surface of the central beta-sheet of ubiquitin, similar to that observed in the RABGEF1/Rabex-5 or POLN/Pol-eta zinc finger [1].

1: Molecular basis of ubiquitin recognition by the autophagy receptor CALCOCO2. Xie X, Li F, Wang Y, Wang Y, Lin Z, Cheng X, Liu J, Chen C, Pan L; Autophagy. 2015;11:1775-1789. PMID:26506893