Belongs to an adhesion system, probably together with the E-cadherin-catenin system, which plays a role in the organization of homotypic, interneuronal and heterotypic cell-cell adherens junctions (AJs) (PubMed:9334353). Nectin- and actin-filament-binding protein that connects nectin to the actin cytoskeleton (PubMed:9334353). May play a key role in the organization of epithelial structures of the embryonic ectoderm (By similarity). Essential for the organization of adherens junctions (By similarity). Homodimer. Interacts with F-actin, nectin and NECTIN3. Essential for the association of nectin and E-cadherin. Isoform 2/s-afadin does not interact with F-actin. Interacts with ZO-1 and occludin, but probably in an indirect manner. Interacts with RIT1, RIT2, NRXN1 and BCR (By similarity). Interacts with ADAM10; the interaction locks ADAM10 at adherens junctions following ADAM10 recruitment to adherens junctions by TSPAN33 (PubMed:30463011). Not found at cell-matrix AJs. Isoform 1 is widely expressed, including in heart, brain, spleen, lung, liver, skeletal muscle, kidney and testis. Isoform 2 is mainly expressed in the brain. Isoform 1 increases the viscosity of F-actin in a dose-dependent manner. Isoform 1 causes F-actin to associate into bundles and meshworks.