Structure of human guanylate-binding protein 1 representing a unique class of GTP-binding proteins

Max-Planck-Institut für Molekulare Physiologie, Dortmund, Germany.
Nature (Impact Factor: 41.46). 03/2000; 403(6769):567-71. DOI: 10.1038/35000617
Source: PubMed


Interferon-gamma is an immunomodulatory substance that induces the expression of many genes to orchestrate a cellular response and establish the antiviral state of the cell. Among the most abundant antiviral proteins induced by interferon-gamma are guanylate-binding proteins such as GBP1 and GBP2. These are large GTP-binding proteins of relative molecular mass 67,000 with a high-turnover GTPase activity and an antiviral effect. Here we have determined the crystal structure of full-length human GBP1 to 1.8 A resolution. The amino-terminal 278 residues constitute a modified G domain with a number of insertions compared to the canonical Ras structure, and the carboxy-terminal part is an extended helical domain with unique features. From the structure and biochemical experiments reported here, GBP1 appears to belong to the group of large GTP-binding proteins that includes Mx and dynamin, the common property of which is the ability to undergo oligomerization with a high concentration-dependent GTPase activity.

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Available from: Louis Renault, Jan 12, 2015
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    • "Guanylate-binding protein 1 (GBP1) is one of the ISGs that most strongly induced by IFNs [9] and belongs to a family of GTPases which are divided into three groups: (1) the large GTPases, also known as GBPs; (2) the small GTPases; (3) the Mx proteins. The human large GTPase family is composed of seven members encoded by a gene cluster located on chromosome 1 [10,11]. The emerging roles of GBP1 in host immune responses have been characterized in in vitro and in vivo models [12-15]. "
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    ABSTRACT: Background Dengue virus (DENV), the causative agent of human Dengue hemorrhagic fever, is a mosquito-borne virus found in tropical and sub-tropical regions around the world. Vaccines against DENV are currently unavailable. Guanylate-binding protein 1 (GBP1) is one of the Interferon (IFN) stimulated genes (ISGs) and has been shown important for host immune defense against various pathogens. However, the role of GBP1 during DENV infection remains unclarified. In this study, we evaluated the relevance of GBP1 to DENV infection in in vitro model. Findings Quantitative RT-PCR (qRT-PCR) and Western blot showed that the expression of mouse Gbp1 was dramatically upregulated in DENV-infected RAW264.7 cells. The intracellular DENV loads were significantly higher in Gbp1 silenced cells compared with controls. The expression levels of selective anti-viral cytokines were decreased in Gbp1 siRNA treated cells, while the transcription factor activity of NF-κB was impaired upon GBP1 silencing during infection. Conclusions Our data suggested that GBP1 plays an antiviral role during DENV infection.
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    • "To identify the target genes regulated by EGFR activation, we performed expression array analysis and found that the most commonly altered expression was from a gene module normally associated with IFN stimulation and Stat function. This included GBP1 (guanylate binding protein 1), initially identified as a type I and II IFN-induced gene, that encodes a 67-kD protein belonging to a large GTPase family, which includes dynamins and Mx proteins (Prakash et al., 2000a,b). In endothelial cells, GBP1 can be induced by IL-1, TNF, and IFN- in vitro (Guenzi et al., 2001, 2003), and it is expressed in these cells in vivo during an inflammatory response (Lubeseder-Martellato et al., 2002) to interfere with angiogenesis and to inhibit the expression of MMP1 (matrix metalloproteinase 1), a collagenase necessary for cell migration through the extracellular matrix (Guenzi et al., 2003). "
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    ABSTRACT: Although GBP1 (guanylate binding protein 1) was among the first interferon-inducible proteins identified, its function is still largely unknown. Epidermal growth factor receptor (EGFR) activation by amplification or mutation is one of the most frequent genetic lesions in a variety of human tumors. These include glioblastoma multiforme (GBM), which is characterized by independent but interrelated features of extensive invasion into normal brain parenchyma, rapid growth, necrosis, and angiogenesis. In this study, we show that EGFR activation promoted GBP1 expression in GBM cell lines through a signaling pathway involving Src and p38 mitogen-activated protein kinase. Moreover, we identified YY1 (Yin Yang 1) as the downstream transcriptional regulator regulating EGFR-driven GBP1 expression. GBP1 was required for EGFR-mediated MMP1 (matrix metalloproteinase 1) expression and glioma cell invasion in vitro. Although deregulation of GBP1 expression did not affect glioma cell proliferation, overexpression of GBP1 enhanced glioma cell invasion through MMP1 induction, which required its C-terminal helical domain and was independent of its GTPase activity. Reducing GBP1 levels by RNA interference in invasive GBM cells also markedly inhibited their ability to infiltrate the brain parenchyma of mice. GBP1 expression was high and positively correlated with EGFR expression in human GBM tumors and cell lines, particularly those of the neural subtype. Together, these findings establish GBP1 as a previously unknown link between EGFR activity and MMP1 expression and nominate it as a novel potential therapeutic target for inhibiting GBM invasion.
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    • "The structures reveal a globular GTPase head connected through an eight–amino acid linker to a middle domain comprised of a three-helix bundle. As expected, the GTPase domain has an overall fold similar to that of GBP1 (Prakash et al., 2000), the closest relative of ATL1–3 in the dynamin superfamily (14, 14, and 16% identical to ATL1, ATL2, and ATL3, respectively). Dynamin superfamily members undergo conformational changes in a manner dependent on their nucleotide-bound state (Ghosh et al., 2006; Chappie et al., 2010). "
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    ABSTRACT: Endoplasmic reticulum (ER) network branching requires homotypic tethering and fusion of tubules mediated by the atlastin (ATL) guanosine triphosphatase (GTPase). Recent structural studies on the ATL soluble domain reveal two dimeric conformers proposed to correspond to a tethered prefusion state and a postfusion state. How the prefusion conformer transitions to the postfusion conformer is unknown. In this paper, we identify an intramolecular salt bridge mediated by two residues outside the GTPase domain near the point of rotation that converts the prefusion dimer to the postfusion state. Charge reversal of either residue blocked ER network branching, whereas a compensatory charge reversal to reestablish electrostatic attraction restored function. In vitro assays using the soluble domain revealed that the salt bridge was dispensable for GTP binding and hydrolysis but was required for forming the postfusion dimer. Unexpectedly, the postfusion conformation of the soluble domain was achieved when bound to the nonhydrolyzable GTP analogue guanosine 5'-[β,γ-imido]triphosphate, suggesting that nucleotide hydrolysis might not be required for the prefusion to postfusion conformational change.
    Full-text · Article · Nov 2011 · The Journal of Cell Biology
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