LabA-like PIN domain of human zinc finger protein 451 and related proteins
Human ZNF451 (also known as COASTER) functions as a transcriptional cofactor in promyelocytic leukemia bodies in the nucleus, it acts as a coactivator or corepressor, depending on the factors with which it interacts. ZNF451 interacts with p300 by the PIN-like domain and down regulates TGF-beta signaling in a p300-dependent and sumoylation-independent manner. This subfamily belongs to LabA-like PIN domain family which includes Synechococcus elongatus PCC 7942 LabA, human ZNF451, uncharacterized Bacillus subtilis YqxD and Escherichia coli YaiI, and the N-terminal domain of a well-conserved group of mainly bacterial proteins with no defined function, which contain a C-terminal LabA_like_C domain. Curiously, a gene labeled NicB from Pseudomonas putida S16, which is described as a putative NADH-dependent hydroxylase involved in the microbial degradation of nicotine also falls into the LabA-like PIN family. The PIN (PilT N terminus) domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found while some others lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons. Matelska et al. recently classified PIN-like domains into distinct groups; this subgroup includes some sequences belonging to one of these, PIN_11.
Comment:based on structure and experimental evidence from PIN-superfamily members belonging to the FEN-like, VapC-like, PRORP-like, and LabA-like families
Comment:The PIN domain superfamily contains three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found. Some members of the superfamily lack several of these key catalytic residues. In this subgroup 4 conserved catalytic residues are found.