title: Novel non-canonical role of STAT1 in Natural Killer cell cytotoxicity.
abstract: STAT1 is an important regulator of NK cell maturation and cytotoxicity. Although the consequences ofStat1-deficiency have been described in detail the underlying molecular functions of STAT1 in NK cells are only partially understood. Here, we describe a novel non-canonical role of STAT1 that was unmasked in NK cells expressing aStat1-Y701Fmutant. This mutation prevents JAK-dependent phosphorylation, subsequent nuclear translocation and cytokine-induced transcriptional activity as verified by RNA-seq analysis. As expectedStat1-Y701Fmice displayed impaired NK cell maturation comparable toStat1-/-animals. In contrastStat1-Y701FNK cells exerted a significantly enhanced cytotoxicityin vitroandin vivocompared toStat1-/-NK cells in the absence of detectable transcriptional activity. We thus investigated the STAT1 interactome using primary NK cells derived fromStat1indmice that inducibly express a FLAG-tagged STAT1. Mass spectrometry revealed that STAT1 directly binds proteins involved in cell junction formation and proteins associated to membrane or membrane-bound vesicles. In line, immunofluorescence studies uncovered the recruitment of STAT1 to the target-cell interphase during NK cell killing. This led us to propose a novel function for STAT1 at the immunological synapse in NK cells regulating tumor surveillance and cytotoxicity.
authors.affiliation: Institute of Pharmacology and Toxicology, Department for Biomedical Sciences, University of Veterinary Medicine Vienna , Vienna, Austria.
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Putz
authors.affiliation: Max F. Perutz Laboratories, University of Vienna , Vienna, Austria.
authors.forename: Andrea
authors.initials: A
authors.lastname: Majoros
authors.affiliation: Institute of Pharmacology and Toxicology, Department for Biomedical Sciences, University of Veterinary Medicine Vienna , Vienna, Austria.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Gotthardt
authors.affiliation: Institute of Pharmacology and Toxicology, Department for Biomedical Sciences, University of Veterinary Medicine Vienna , Vienna, Austria.
authors.forename: Michaela
authors.initials: M
authors.lastname: Prchal-Murphy
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna, Austria.
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Zebedin-Brandl
authors.affiliation: Institute of Pharmacology and Toxicology, Department for Biomedical Sciences, University of Veterinary Medicine Vienna , Vienna, Austria.
authors.forename: Daniela Alexandra
authors.initials: DA
authors.lastname: Fux
authors.affiliation: Boehringer Ingelheim RCV GmBH & CO KG , Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schlattl
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine , St Louis, MO, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Schreiber
authors.affiliation: Boehringer Ingelheim RCV GmBH & CO KG, Vienna, Austria; Division of Molecular Immunology, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Carotta
authors.affiliation: Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria; Biomodels Austria, Vienna, Austria.
authors.forename: Mathias
authors.initials: M
authors.lastname: Müller
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna , Vienna, Austria.
authors.forename: Christopher
authors.initials: C
authors.lastname: Gerner
authors.affiliation: Max F. Perutz Laboratories, University of Vienna , Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Decker
authors.affiliation: Institute of Pharmacology and Toxicology, Department for Biomedical Sciences, University of Veterinary Medicine Vienna , Vienna, Austria.
authors.forename: Veronika
authors.initials: V
authors.lastname: Sexl
keywords: Interactome; NK cell; STAT1; tumor surveillance; vesicle