HAP1 and schizophrenia: In addition, Kalirin interacts with many different proteins including deleted in schizophrenia 1 (DISC1), a major risk factor for schizophrenia, the inducible form of nitric oxide synthase (iNOS; NOS2), Huntingtin-associated protein 1 (HAP1) and peptidylglycine α-amidating monooxygenase, an essential enzyme for neuropeptide biosynthesis [7-11].