Nitric Oxide Synthase 1 Adaptor Protein (NOS1AP)

NOS1AP encodes a cytosolic protein that binds to the signaling molecule, neuronal nitric oxide synthase (nNOS). This protein has a C-terminal PDZ-binding domain that mediates interactions with nNOS and an N-terminal phosphotyrosine binding (PTB) domain that binds to the small monomeric G protein, Dexras1. Studies of the related mouse and rat proteins have shown that this protein functions as an adapter protein linking nNOS to specific targets, such as Dexras1 and the synapsins. NOS1AP polymorphisms has been associated with the QT interval length. CAPON appears to have 2 alternate splice forms, one encoding a 125-amino acid protein and the other encoding a 327-amino acid protein. The 125-amino acid C-terminal fragment of CAPON specifically interacted with NOS1 in a 2-hybrid system.