PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of afadin (AFDN, also known as ALL1-fused gene from chromosome 6 protein (AF6) and MLLT4), and related domains. AFDN belongs to the adhesion system, probably together with the E-cadherin-catenin system, that plays a role in the organization of homotypic, interneuronal, and heterotypic cell-cell adherens junctions. The AFDN PDZ domain interaction partners include poliovirus receptor-related protein PRR2/nectin, the junctional adhesion molecule (JAM), the breakpoint-cluster-region protein (BCR), connexin36 (Cx36), and a subset of Eph-related receptor tyrosine kinases; it can also bind low molecular weight ligands, in competition with a natural peptide ligand. Other AFDN-binding proteins have been identified. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This AFDN family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.
Feature 1:peptide binding site [polypeptide binding site]
Evidence:
Comment:based on canonical PDZ domains with structure
Comment:PDZ domains specifically recognize and bind to short C-terminal peptide motifs, but can also recognize internal peptide motifs and certain lipids
Structure:2AIN: PDZ domain of human afadin binds C- terminal peptide of breakpoint cluster region (Bcr) protein, contacts at 4A
Comment:the afadin PDZ domain bind to the C-terminus of Bcr efficiently after phosphorylation of afadin by the Bcr kinase; complex exhibits a noncononical binding mode of PDZ to peptide
Jiyao W et al.(2023). "The conserved domain database in 2023.",