NOS1AP (nitric oxide synthase 1 adaptor protein) is a critical adapter protein that regulates neuronal nitric oxide (NO) synthesis through its association with neuronal NOS (nNOS) 1. Structurally, NOS1AP contains an N-terminal phosphotyrosine-binding (PTB) domain and a C-terminal PDZ ligand motif that enables interactions with nNOS and synapsins at glutamatergic synapses 1. The protein mediates indirect activation of RASD1 through nNOS and competes with PSD-95 for nNOS binding, thereby modulating NMDAR-driven nNOS signaling 2. NOS1AP regulates dendritic branching during neurodevelopment, with both long and short isoforms suppressing dendrite branching in human neurons 3. In kidney podocytes, NOS1AP promotes CDC42 activation for podosome formation 4. Disease relevance spans neuropsychiatric conditions: NOS1AP polymorphisms associate with schizophrenia, bipolar disorder, and personality disorders, with genetic variants showing interactions with childhood trauma in antisocial and paranoid personality disorder development 56. Clinical significance includes elevated NOS1AP expression in schizophrenia postmortem brain tissue and nephrotic syndrome 22 association. NOS1AP also participates in cancer-related pathways, competing with tumor suppressor Scribble for binding partners in breast cancer progression 7.