Palmitoylome profiling reveals S-palmitoylation-dependent antiviral activity of IFITM3

The Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York, USA.
Nature Chemical Biology (Impact Factor: 13). 08/2010; 6(8):610-4. DOI: 10.1038/nchembio.405
Source: PubMed

ABSTRACT Identification of immune effectors and the post-translational modifications that control their activity is essential for dissecting mechanisms of immunity. Here we demonstrate that the antiviral activity of interferon-induced transmembrane protein 3 (IFITM3) is post-translationally regulated by S-palmitoylation. Large-scale profiling of palmitoylated proteins in a dendritic cell line using a chemical reporter strategy revealed over 150 lipid-modified proteins with diverse cellular functions, including innate immunity. We discovered that S-palmitoylation of IFITM3 on membrane-proximal cysteines controls its clustering in membrane compartments and its antiviral activity against influenza virus. The sites of S-palmitoylation are highly conserved among the IFITM family of proteins in vertebrates, which suggests that S-palmitoylation of these immune effectors may be an ancient post-translational modification that is crucial for host resistance to viral infections. The S-palmitoylation and clustering of IFITM3 will be important for elucidating its mechanism of action and for the design of antiviral therapeutics.

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Available from: Carolina B López, Sep 26, 2015
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    • "However, recent evidence also supports the cytoplasmic localization of the N-terminus (Bailey et al., 2013; Yount et al., 2012). In addition to the plasma membrane, IFITM proteins are also observed in the endoplasmic reticulum (ER) and endosomes (Alber and Staeheli, 1996; Brass et al., 2009; Feeley et al., 2011; Jia et al., 2012; Lu et al., 2011; Yang et al., 2007; Yount et al., 2010; Zucchi et al., 2004). The localization of IFITM3 in late endosomes is important for inhibiting IAV infection, because ectopic expression of IFITM3, or its induced expression by interferon, causes expansion of late endosomes and lysosomes and results in the sequestration of endocytosed IAV particles in these acidic membrane compartments (Feeley et al., 2011; Huang et al., 2011). "
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    ABSTRACT: Interferon-induced transmembrane (IFITM) proteins inhibit the infection of a wide range of viruses including human immunodeficiency virus type 1 (HIV-1). At present, little is known about how viruses overcome IFITM restriction. In this study, we have utilized HIV-1 as a model and selected IFITM1-resistant viruses after multiple passages of HIV-1 in IFITM1-expressing SupT1 cells. Sequencing the entire viral genome revealed several mutations in the vpu and envelope genes, among which mutations Vpu34 and EnvG367E together enable efficient HIV-1 replication in IFITM1-expressing cells. Vpu34 introduces a stop codon at amino acid position 35 of Vpu, whereas EnvG367E changes the G367 residue at the CD4-binding site of gp120. These two mutations do not appear to overcome the downregulation of viral p24 expression caused by IFITM1, but rather enhance HIV-1 replication by promoting cell-to-cell virus transmission. Altogether, our data demonstrate that HIV-1 can mutate to evade IFITM1 restriction by increasing cell-to-cell transmission.
    Virology 04/2014; s 454–455(1):11–24. DOI:10.1016/j.virol.2014.01.020 · 3.32 Impact Factor
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    • "Previous studies showed that IFITM3 belongs to a family of murine genes [9], which are short, 2-transmembrane-domain proteins (5-18 kDa) with high core sequence similarity but divergent N- and C-termini. The human homologues (IFITM1, IFITM2, and IFITM3) are clustered on chromosome 11 within an 18-kb genomic sequence [7,10,11], and mediates cellular processes, including cell adhesion, immune-cell regulation, germ-cell homing and maturation, and bone mineralization [8,11-16]. "
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    ABSTRACT: Interferon induced transmembrane protein 3 (IFITM3) is transcribed in most tissues and highly interferon-inducible. However, the role of IFITM3 in cancer is still poorly understood. Expression levels ofIFITM3were analyzed in 60 glioma patients by immunohistochemistry (IHC). Following closely, we investigated the phenotype of IFITM3 knockdown on glioma cell growth and tumorigenesis in vitro using lentivirus-mediated loss-of-function strategy. Depletion of IFITM3in U251 cells dramatically inhibited cell proliferation and colony formation, which demonstrated that reduced IFITM3 protein levels could cause inhibition of tumorigenesis. Knockdown of IFITM3 also induced cell cycle arrest in G0/G1 phase, especially in the sub-G1 phase representing apoptotic cells. In addition, the migration of U251 cells was visibly weakened after IFITM3 knockdown, as determined by Transwell assay. Our findings provide new evidence that IFITM3 plays an important role in glioma cell growth and migration, suggesting that silencing of IFITM3 by RNA interference (RNAi) may be a potential approach to suppress glioma growth.
    BMC Neurology 12/2013; 13(1):210. DOI:10.1186/1471-2377-13-210 · 2.04 Impact Factor
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    • "More than 400 putative P. falciparum palmitoylated proteins were identified in the highly enriched fraction (Jones et al., 2012). This is significantly more than what has been reported to date for the palmitome of Saccharomyces cerevisiae (50 proteins) (Roth et al., 2006), T. brucei (124 proteins) (Emmer et al., 2011) and mammalian cells (between 125 and 260 proteins) (Kang et al., 2008; Martin and Cravatt, 2009; Yount et al., 2010). These findings led to the assumption that P. falciparum makes substantial use of palmitoylation, wider than previously thought, with implications for many diverse biological processes including signalling, development, invasion as well as cytoadherence and drug resistance (Jones et al., 2012). "
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    ABSTRACT: Post-translational modifications (PTMs) are refined, rapidly responsive and powerful ways to modulate protein function. Among PTMs, acylation is now emerging as a widespread modification exploited by eukaryotes, bacteria and viruses to control biological processes. Protein palmitoylation involves the attachment of palmitic acid, also known as hexadecanoic acid, to cysteine residues of integral and peripheral membrane proteins and increases their affinity for membranes. Importantly, similar to phosphorylation, palmitoylation is reversible and is becoming recognised as instrumental for the regulation of protein function by modulating protein interactions, stability, folding, trafficking and signalling. Palmitoylation appears to play a central role in the biology of the Apicomplexa, regulating critical processes such as host cell invasion which is vital for parasite survival and dissemination. The recent identification of over 400 palmitoylated proteins in Plasmodium falciparum erythrocytic stages illustrates the broad spread and impact of this modification on parasite biology. The main enzymes responsible for protein palmitoylation are multi-membrane protein S-acyl transferases (PATs) harbouring a catalytic Asp-His-His-Cys (DHHC) motif. A global functional analysis of the repertoire of PATs in Toxoplasma gondii and Plasmodium berghei has recently been performed. The essential nature of some of these enzymes illustrates the key roles played by this PTM in the corresponding substrates implicated in fundamental processes such as parasite motility and organelle biogenesis. Toward a better understanding of the depalmitoylation event, a protein with palmitoyl protein thioesterase (PPT) activity has been identified in T. gondii. TgPPT1/TgASH1 is the main target of specific acyl protein thioesterase inhibitors but is dispensable for parasite survival, suggesting the implication of other genes in depalmitoylation. Palmitoylation/depalmitoylation cycles are now emerging as potential novel regulatory networks and T. gondii represents a superb model organism in which to explore their significance.
    International journal for parasitology 10/2013; 44(2). DOI:10.1016/j.ijpara.2013.09.004 · 3.87 Impact Factor
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