autophagy receptor zinc finger-C2H2 domain found in calcium-binding and coiled-coil domain-containing proteins, TAX1BP1 and similar proteins
The family includes calcium-binding and coiled-coil domain-containing proteins (CALCOCO1 and CALCOCO2), TAX1BP1 and similar proteins. CALCOCO1, also called calphoglin, or coiled-coil coactivator protein, or Sarcoma antigen NY-SAR-3, functions as a coactivator for aryl hydrocarbon and nuclear receptors (NR). CALCOCO2, also called antigen nuclear dot 52 kDa protein, or nuclear domain 10 protein NDP52, or nuclear domain 10 protein 52, or nuclear dot protein 52, is an ubiquitin-binding autophagy receptor involved in the selective autophagic degradation of invading pathogens. TAX1BP1, also called TRAF6-binding protein (T6BP), is a novel ubiquitin-binding adaptor protein involved in the negative regulation of the NF-kappaB transcription factor, a key player in inflammatory responses, immunity and tumorigenesis. The family also includes Drosophila melanogaster Spindle-F (Spn-F) that is the central mediator of IK2 kinase-dependent dendrite pruning in drosophila sensory neurons. This model corresponds to the C2H2-type zinc binding domain found in family members. It 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.