1yvl
From Proteopedia
Structure of Unphosphorylated STAT1
Structural highlights
Disease[STAT1_HUMAN] Defects in STAT1 are the cause of STAT1 deficiency complete (STAT1D) [MIM:613796]. STAT1D is a disorder characterized by susceptibility to severe mycobacterial and viral infections. Affected individuals can develop disseminated infections and die of viral illness.[1] [2] Defects in STAT1 are a cause of Mendelian susceptibility to mycobacterial disease (MSMD) [MIM:209950]; also known as familial disseminated atypical mycobacterial infection. This rare condition confers predisposition to illness caused by moderately virulent mycobacterial species, such as Bacillus Calmette-Guerin (BCG) vaccine and environmental non-tuberculous mycobacteria, and by the more virulent Mycobacterium tuberculosis. Other microorganisms rarely cause severe clinical disease in individuals with susceptibility to mycobacterial infections, with the exception of Salmonella which infects less than 50% of these individuals. The pathogenic mechanism underlying MSMD is the impairment of interferon-gamma mediated immunity whose severity determines the clinical outcome. Some patients die of overwhelming mycobacterial disease with lepromatous-like lesions in early childhood, whereas others develop, later in life, disseminated but curable infections with tuberculoid granulomas. MSMD is a genetically heterogeneous disease with autosomal recessive, autosomal dominant or X-linked inheritance.[3] [4] [5] Defects in STAT1 are the cause of familial candidiasis type 7 (CANDF7) [MIM:614162]. A primary immunodeficiency disorder with altered immune responses and impaired clearance of fungal infections, selective against Candida. It is characterized by persistent and/or recurrent infections of the skin, nails and mucous membranes caused by organisms of the genus Candida, mainly Candida albicans. Note=STAT1 mutations in patients with autosomal dominant candidiasis lead to defective responses of type 1 and type 17 helper T-cells, characterized by reduced production of interferon-alpha, interleukin-17, and interleukin-22. These cytokines are crucial for the antifungal defense of skin and mucosa (PubMed:21714643).[6] [7] Function[STAT1_HUMAN] Signal transducer and transcription activator that mediates cellular responses to interferons (IFNs), cytokine KITLG/SCF and other cytokines and growth factors. Following type I IFN (IFN-alpha and IFN-beta) binding to cell surface receptors, signaling via protein kinases leads to activation of Jak kinases (TYK2 and JAK1) and to tyrosine phosphorylation of STAT1 and STAT2. The phosphorylated STATs dimerize, associate with ISGF3G/IRF-9 to form a complex termed ISGF3 transcription factor, that enters the nucleus. ISGF3 binds to the IFN stimulated response element (ISRE) to activate the transcription of interferon stimulated genes, which drive the cell in an antiviral state. In response to type II IFN (IFN-gamma), STAT1 is tyrosine- and serine-phosphorylated. It then forms a homodimer termed IFN-gamma-activated factor (GAF), migrates into the nucleus and binds to the IFN gamma activated sequence (GAS) to drive the expression of the target genes, inducing a cellular antiviral state. Becomes activated in response to KITLG/SCF and KIT signaling. May mediate cellular responses to activated FGFR1, FGFR2, FGFR3 and FGFR4.[8] [9] [10] [11] [12] Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure has been determined at 3.0 A resolution for an unphosphorylated STAT1 (1-683) complexed with a phosphopeptide derived from the alpha chain of interferon gamma (IFNgamma) receptor. Two dimer interfaces are seen, one between the N domains (NDs) (amino acid residues 1-123) and the other between the core fragments (CFs) (residues 132-683). Analyses of the wild-type (wt) and mutant STAT1 proteins by static light scattering, analytical ultracentrifugation, and coimmunoprecipitation suggest that STAT1 is predominantly dimeric prior to activation, and the dimer is mediated by the ND interactions. The connecting region between the ND and the CF is flexible and allows two interconvertable orientations of the CFs, termed "antiparallel" or "parallel," as determined by SH2 domain orientations. Functional implications of these dimer conformations are discussed. Also revealed in this structure is the detailed interaction between STAT1 SH2 domain and its docking site on IFNgamma receptor. Structural bases of unphosphorylated STAT1 association and receptor binding.,Mao X, Ren Z, Parker GN, Sondermann H, Pastorello MA, Wang W, McMurray JS, Demeler B, Darnell JE Jr, Chen X Mol Cell. 2005 Mar 18;17(6):761-71. PMID:15780933[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Large Structures | Chen, X | Darnell, J E | Demeler, B | Mao, X | McMurray, J S | Parker, G N | Pastorello, M A | Ren, Z | Sondermann, H | Wang, W | Signaling protein