Signal transducer and activator of transcription (STAT) proteins are critical for the regulation of numerous biological processes. In cattle, microarray analyses identified STAT1 as a differentially expressed gene in the endometrium during the peri-implantation period. To gain new insights about STAT1 during the oestrous cycle and early pregnancy, we investigated STAT1 transcript and protein ex...

This study examines the role of the signal transducer and activator of transcription 1 (STAT1) in induction of lipopolysaccharide (LPS)-stimulated gene expression both in vitro and in vivo. LPS-induced expression of an interferon (IFN)-inducible 10-kDa protein (IP-10), IFN regulatory factor-1 (IRF-1), and inducible nitric oxide synthase (iNOS) mRNAs was severely impaired in macrophages prepared...

Autosomal Dominant Chronic Mucocutaneous Candidiasis (AD-CMC) is characterized by defective T cell immunity, leading to fungal infections limited to mucosal surfaces. Recently it was discovered that mutations in the coiled-coil (CC) domain of STAT1 are the cause of AD-CMC. STAT1 deficiency has been implicated in experimental models of oesophageal cancer (EC) and head and neck carcinoma (HNC). B...

The Sendai virus (SeV) C proteins are known to interact with Stat1 to prevent interferon (IFN)-induced pY701-Stat1 formation and IFN signaling. Nevertheless, pY701-Stat1 levels paradoxically increase during SeV infection. The C proteins also induce bulk Stat1 instability in some cells, similar to rubulavirus V proteins. We have found that SeV infection increases pY701-Stat1 levels even in cells...

Signal transducer and activator of transcription 1 (STAT1) mediates gene expression in response to cytokines and growth factors. Activation of STAT1 is achieved through its tyrosine phosphorylation, a process that involves Jak tyrosine kinases. Here we show that STAT1, although phosphorylated on Y701, is unable to localize in the nucleus in the absence of Jak1 or Jak1 kinase activity. In contra...

The protozoan Toxoplasma gondii actively modulates cytokine-induced JAK/STAT signaling pathways to facilitate survival within the host, including blocking IFNγ-mediated STAT1-dependent proinflammatory gene expression. We sought to further characterize inhibition of STAT1 signaling in infected murine dendritic cells (DC) because this cell type has not previously been examined, yet is known to se...

The S-phase kinase-associated protein 2 (Skp2) is an F-box protein that serves as a subunit of the Skp1-Cullin-F-box ubiquitin protein ligase complex. Skp2 is overexpressed in many tumors and promotes tumor formation through its ability to induce the degradation of proteins with antiproliferative and tumor-suppressor functions, such as p27(Kip1). The signal transducer and activator of transcrip...

Mice lacking the Stat1 interferon signaling gene were infected with herpes simplex virus type 1 (HSV-1) or an attenuated recombinant lacking virion host shutoff (Delta vhs). Delta vhs virus-infected Stat1(-/-) mice showed levels of replication equivalent to that of the wild-type virus-infected control mice but reduced relative to wild-type virus-infected Stat1(-/-) mice. Stat1 deficiency reliev...

Signal transducer and activator of transcription 1 (Stat1) is a key player in responses to interferons (IFN). Mutations of Stat1 cause severe immune deficiencies in humans and mice. Here we investigate the importance of Stat1 signaling for the innate and secondary immune response to the intracellular bacterial pathogen Listeria monocytogenes (Lm). Cell type-restricted ablation of the Stat1 gene...

T-bet and STAT1 regulate IFN-gamma gene transcription in CD4+ T cells, which mediate protection against Leishmania. Here we show that T-bet and STAT1 are required for the induction of an efficient Th1 response during Leishmania donovani infection, but they play distinct roles in determining disease outcome. Both STAT1(-/-) and T-bet(-/-) mice failed to mount a Th1 response, but STAT1(-/-) mice ...