Identification and characterization of NOS1APc interacting proteins

Abstract

The current study characterizes novel interacting proteins for the neuronal nitric oxide synthase 1 adaptor protein (NOS1AP) isoform NOS1APc. NOS1APc is a 100kDa isoform of NOS1AP (herein NOS1APa) that contains a unique 30kDa C-terminal extension that eliminates the interaction with nNOS. Immunoprecipitations using NOS1APc isoform specific antibodies revealed the potential for alternate isoforms of NOS1AP. Cloning techniques were used to identify three new NOS1AP isoforms, NOS1APd, NOS1APe and NOS1APf. All isoforms except for NOS1APf retain the ability to interact with the polarity protein Scribble. A targeted proteomic screen for NOS1APc established pyruvate carboxylase (PCB) as a potential interacting protein. Through over-expression and immunoprecipitation experiments, it was identified that NOS1APc plausibly interacts with PCB. Finally, an interaction between NOS1APc and ephrinB3 was characterized. Taken together, these data suggest differences exist between NOS1APa and NOS1APc in their ability to bind to certain proteins and therefore may act in different protein-protein complexes.