Identification and Characterization of a Loss-of-Function Human MPYS Variant

Integrated Department of Immunology, University of Colorado Denver School of Medicine and National Jewish Health, Denver, CO 80206-2762, USA.
Genes and immunity (Impact Factor: 2.91). 01/2011; 12(4):263-9. DOI: 10.1038/gene.2010.75
Source: PubMed


MPYS, also known as STING and MITA, is an interferon (IFN)β stimulator essential for host defense against RNA, DNA viruses and intracellular bacteria. MPYS also facilitates the adjuvant activity of DNA vaccines. Here, we report identification of a distinct human MPYS haplotype that contains three non-synonymous single nucleotide polymorphisms (SNPs), R71H-G230A-R293Q (thus, named the HAQ haplotype). We estimate, in two cohorts (1,074 individuals), that ∼3% of Americans are homozygous for this HAQ haplotype. HAQ MPYS exhibits a > 90% loss in the ability to stimulate IFNβ production. Furthermore, fibroblasts and macrophage cells expressing HAQ are defective in Listeria monocytogenes infection-induced IFNβ production. Lastly, we find that the loss of IFNβ activity is due primarily to the R71H and R293Q SNPs in HAQ. We hypothesize that individuals carrying HAQ may exhibit heightened susceptibility to viral infection and respond poorly to DNA vaccines.

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Available from: John Cambier, Dec 22, 2014
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    • "Importantly, although there are four antigenically distinct serotypes of DENV (DENV-1 to -4), these observations were not limited to any particular serotype as STING degradation was observed during infection with DENV-1 and several different DENV-2 strains [9] [12]. The consensus cleavage site for the DENV protease is located towards the N-terminus of the 379-residue STING molecule ( 94 RR#GA 97 ) [9] [12], close to a cysteine-rich redox motif ( 88 CXXC 91 ) that is required for STING dimerisation and the induction of type I IFN [9] [40]. Using a STING construct containing an N-terminal HA tag and a C-terminal V5 tag, the Lin group demonstrated that the STING cleavage products co-migrate on western blots with STING truncation mutants designed around the predicted cleavage site [12], suggesting that this sequence is in fact the target site for NS2B/3. "
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    ABSTRACT: STING has emerged in recent years as an important signalling adaptor in the activation of type I interferon responses during infection with DNA viruses and bacteria. An increasing body of evidence suggests that STING also modulates responses to RNA viruses, though the mechanisms remain less clear. In this review, we give a brief overview of the ways in which STING facilitates sensing of RNA viruses. These include modulation of RIG-I-dependent responses through STING's interaction with MAVS, and more speculative mechanisms involving the DNA sensor cGAS, and sensing of membrane remodelling events. We then provide an in-depth literature review to summarise the known mechanisms by which RNA viruses of the families Flaviviridae and Coronaviridae evade sensing through STING. Our own work has shown that the NS2B/3 protease complex of the flavivirus Dengue virus binds and cleaves STING, and that an inability to degrade murine STING may contribute to host restriction in this virus. We contrast this to the mechanism employed by the distantly related hepacivirus Hepatitis C virus, in which STING is bound and inactivated by the NS4B protein. Finally, we discuss STING antagonism in the coronaviruses SARS coronavirus and Human coronavirus NL63, which disrupt K63-linked polyubiquitination and dimerisation of STING (both of which are required for STING-mediated activation of IRF-3) via their papain-like proteases. We draw parallels with less-well characterised mechanisms of STING antagonism in related viruses, and place our current knowledge in the context of species tropism restrictions that potentially affect the emergence of new human pathogens.
    Full-text · Article · Aug 2014 · Cytokine & Growth Factor Reviews
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    • "The fourth has three substitutions: R71H, G230A, and R293Q (to be designated HAQ). This observation is similar to the previous report by Jin et al [28] who have identified that HAQ is a loss-of-function hSTING variant from two cohorts of American DNA samples. In this work, we determine whether hSTING SNPs could affect the recognition with exogenous cyclic dinucleotides from bacterium and metazoan. "
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    ABSTRACT: The STING (stimulator of interferon genes) protein can bind cyclic dinucleotides to activate the production of type I interferons and inflammatory cytokines. The cyclic dinucleotides can be bacterial second messengers c-di-GMP and c-di-AMP, 3'5'-3'5' cyclic GMP-AMP (3'3' cGAMP) produced by Vibrio cholerae and metazoan second messenger 2'5'-3'5' Cyclic GMP-AMP (2'3' cGAMP). Analysis of single nucleotide polymorphism (SNP) data from the 1000 Genome Project revealed that R71H-G230A-R293Q (HAQ) occurs in 20.4%, R232H in 13.7%, G230A-R293Q (AQ) in 5.2%, and R293Q in 1.5% of human population. In the absence of exogenous ligands, the R232H, R293Q and AQ SNPs had only modest effect on the stimulation of IFN-β and NF-κB promoter activities in HEK293T cells, while HAQ had significantly lower intrinsic activity. The decrease was primarily due to the R71H substitution. The SNPs also affected the response to the cyclic dinucleotides. In the presence of c-di-GMP, the R232H variant partially decreased the ability to activate IFN-βsignaling, while it was defective for the response to c-di-AMP and 3'3' cGAMP. The R293Q dramatically decreased the stimulatory response to all bacterial ligands. Surprisingly, the AQ and HAQ variants maintained partial abilities to activate the IFN-β signaling in the presence of ligands due primarily to the G230A substitution. Biochemical analysis revealed that the recombinant G230A protein could affect the conformation of the C-terminal domain of STING and the binding to c-di-GMP. Comparison of G230A structure with that of WT revealed that the conformation of the lid region that clamps onto the c-di-GMP was significantly altered. These results suggest that hSTING variation can affect innate immune signaling and that the common HAQ haplotype expresses a STING protein with reduced intrinsic signaling activity but retained the ability to response to bacterial cyclic dinucleotides.
    Full-text · Article · Oct 2013 · PLoS ONE
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    • "Variations in the hSTING locus have been documented by Jin et al. (2011b). Approximately 18% of humans in two large cohorts, totaling over 1,000 individuals, were found to be heterozygous for the H232 allele, with the more prevalent allele being R232 (thus, it should be considered a wild-type allele). "
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    ABSTRACT: Cyclic dinucleotides (CDNs) have been previously recognized as important secondary signaling molecules in bacteria and, more recently, in mammalian cells. In the former case, they represent secondary messengers affecting numerous responses of the prokaryotic cell, whereas in the latter, they act as agonists of the innate immune response. Remarkable new discoveries have linked these two patterns of utilization of CDNs as secondary messengers and have revealed unexpected influences they likely had on shaping human genetic variation. This Review summarizes these recent insights and provides a perspective on future unanswered questions in this exciting field.
    Full-text · Article · Aug 2013 · Cell
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