In a targeted proteomic screen to identify polarity protein complexes, a number of Scribble (Scrib) -associating proteins were identified; of particular interest was the Nitric Oxide Synthase 1 Adaptor Protein (NOS1AP). NOS1AP contains an N-terminal phosphotyrosine binding (PTB) domain and a C-terminal PSD-95/Dlg homology/ZO-1 (PDZ) binding motif that associates with neuronal NOS (NOS1). We show that the PTB domain of NOS1AP associates with the fourth PDZ domain of Scrib. We identified NOS1AP binding partners including three key regulators of dendritic spine formation, beta-Pix, Git1, and PAK, which require Scrib to associate with NOS1AP. Overexpression of NOS1AP in cultured hippocampal neurons increases dendritic protrusions, a process dependent on the PTB domain. The increase in dendritic protrusions can be blocked by the co-expression of a dominant negative Rac construct. NOS1AP, and the PTB domain of NOS1AP influence Rac activity. Together these data suggest that Scrib and NOS1AP function as important scaffolding proteins in the mammalian synapse and that NOS1AP functions in the dendritic spine by influencing Rho GTPase activity.

The current study characterizes a novel isoform of the Nitric Oxide Synthase 1 Adaptor Protein (NOS1AP), herein NOS1APc. NOS1APc was identified in a proteomic screen for Scribble interacting proteins. Northern blot analysis revealed a 7kb transcript that was present in a number of different tissues and cell lines. Highest levels were detected in the cerebellum. In situ hybridization studies revealed NOS1APc mRNA throughout the cortex and hippocampus. In addition, cerebellar Purkinje cells and different brainstem nuclei also contained NOS1APc mRNA. Antibodies directed against NOS1APc revealed a 100 kDa protein, while immunohistochemical staining revealed high levels of this protein within the molecular layer of the cerebellum. Finally, immunocytochemical studies using isolated primary astrocytes revealed a subset of BrdU positive nuclei that co-expressed NOS1APc, suggesting that this protein may function in some capacity in cell-cycle progression.

QTc-Zeit Verlängerungen sind aufgrund potentieller Übergänge in lebensbedrohliche Tachyarrhythmien Gegenstand vieler Arbeiten. Einer der Häufigsten Risikofaktoren ist die Einnahme von typischen bzw. atypischen Antipsychotika. Mehrere Studien belegen darüber hinaus genetische Einflüsse und zeigen, dass das homozygote Vorhandensein von rs12143842(T) und rs10494366(G) in NOS1AP einen verlängernden Einfluss auf die QTc-Zeit hat. Zudem scheinen oben genannte Polymorphismen von NOS1AP bei der Entwicklung schizophrener Psychosen eine Rolle zu spielen. In bisherigen Studien wurde immer nur getrennte Analysen hinsichtlich der genannten Risikofaktoren vorgenommen. In dieser Arbeit soll erstmals der gemeinsame Einfluss von Psychopharmaka und den zwei beschriebenen Polymorphismen von NOS1AP bei Patienten mit Schizophrenie untersucht werden. / The prolongation of the QTc-Time interval is a well examined phenomenon due to the risk of suffering a life threatening tachyarrhythmia. In patients with schizophrenia, several risk factors have been identified one of which is taking antipsychotic medication. Genetic variation in NOS1AP polymorphisms rs12143845 (T) and rs10494366 (G) are also found to be significant risk factors. Furthermore, NOS1AP is associated with a higher risk of developing schizophrenic psychosis. This study aims to detect the impact on QTc prolongation in an analysis of combined risk factors in patients with schizophrenia.