Human viperin catalyzes the modification of <scp>GPP</scp> and <scp>FPP</scp> potentially affecting cholesterol synthesis

Mikulecký, Pavel; Андреева, Е.Р.; Amara, Patricia; Weissenhorn, Winfríed; Nicolet, Yvain; Machebœuf, Pauline

doi:10.1002/1873-3468.12941

Cited by 12 publications

(14 citation statements)

References 40 publications

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“…Our work presented here reached different conclusions when compared with two recent studies of in vitro reconstitution of the viperin-catalyzed reactions (37,38). First, Honarmand Ebrahimi et al (37) reported an in vitro study of the recombinant viperin from fungal Thielavia terrestris (TteViperin), indicating the radical addition of 5Ј-dA ⅐ to UDPglucose.…”

Section: Catalysis Of Radical C-c Double Bond Addition By Viperincontrasting

confidence: 54%

“…The recently published crystal structure of viperin from Mus musculus (Mmu-Viperin) provides molecular insight into viperin as a radical SAM enzyme (36), but the study did not reveal possible biological substrate(s) of viperin. More recently, two studies described the in vitro reconstitution of viperin-catalyzed reactions and resulted in two different conclusions (37,38). Based on our study presented here, we have disagreements with both studies, and we will discuss them below.…”

mentioning

confidence: 71%

“…Mikulecky et al (38) concluded that GPP and FPP are the substrates of HsaViperin, mainly based on the following two observations. First, the production of 5Ј-dA is significantly more pronounced in the presence of GPP and FPP when compared with IPP and DMAPP.…”

Section: Catalysis Of Radical C-c Double Bond Addition By Viperinmentioning

confidence: 99%

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Reconstitution and substrate specificity for isopentenyl pyrophosphate of the antiviral radical SAM enzyme viperin

Chakravarti

Selvadurai

Shahoei

et al. 2018

Journal of Biological Chemistry

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Viperin is a radical SAM enzyme that has been shown to possess antiviral activity against a broad spectrum of viruses; however, its molecular mechanism is unknown. We report here that recombinant fungal and archaeal viperin enzymes catalyze the addition of the 5'-deoxyadenosyl radical (5'-dA) to the double bond of isopentenyl pyrophosphate (IPP), producing a new compound we named adenylated isopentyl pyrophosphate (AIPP). The reaction is specific for IPP, as other pyrophosphate compounds involved in the mevalonate biosynthetic pathway did not react with 5'-dA Enzymatic reactions employing IPP derivatives as substrates revealed that any chemical change in IPP diminishes its ability to be an effective substrate of fungal viperin. Mutational studies disclosed that the hydroxyl group on the side chain of Tyr-245 in fungal viperin is the likely source of hydrogen in the last step of the radical addition, providing mechanistic insight into the radical reaction catalyzed by fungal viperin. Structure-based molecular dynamics (MD) simulations of viperin interacting with IPP revealed a good fit of the isopentenyl motif of IPP to the active site cavity of viperin, unraveling the molecular basis of substrate specificity of viperin for IPP. Collectively, our findings indicate that IPP is an effective substrate of fungal and archaeal viperin enzymes and provide critical insights into the reaction mechanism.

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Section: Catalysis Of Radical C-c Double Bond Addition By Viperincontrasting

confidence: 54%

mentioning

confidence: 71%

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Reconstitution and substrate specificity for isopentenyl pyrophosphate of the antiviral radical SAM enzyme viperin

Chakravarti

Selvadurai

Shahoei

et al. 2018

Journal of Biological Chemistry

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“…Various studies had previously linked viperin to the downregulation of cholesterol biosynthesis (39, 46, 55), but the effect of viperin expression of cellular cholesterol biosynthesis had not been investigated. To examine this question, HEK293T cells were grown in reduced serum media containing lipoprotein-depleted serum to minimize uptake of exogenous cholesterol (56).…”

Section: Resultsmentioning

confidence: 99%

Viperin inhibits cholesterol biosynthesis and interacts with enzymes in the cholesterol biosynthetic pathway

Grunkemeyer

Ghosh

Patel

et al. 2021

Preprint

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Many enveloped viruses bud from cholesterol-rich lipid rafts on the cell membrane. Depleting cellular cholesterol impedes this process and results in viral particles with reduced viability. Viperin (virus inhibitory protein endoplasmic reticulum-associated, interferon-induced) is an ER membrane-associated enzyme that when expressed in response to viral infections exerts broad-ranging antiviral effects, including inhibiting the budding of some enveloped viruses. Here we have investigated the effect of viperin expression on cholesterol biosynthesis. We found that viperin expression reduces cholesterol levels by 20 to 30 % in HEK293T cells. A proteomic screen of the viperin interactome identified several cholesterol biosynthetic enzymes among the top hits. The two most highly enriched proteins were lanosterol synthase and squalene monooxygenase, enzymes that catalyze key steps establishing the sterol carbon skeleton. Co-immunoprecipitation experiments established that viperin, lanosterol synthase and squalene monooxygenase form a complex at the ER membrane. Co-expression of viperin was found to significantly inhibit the specific activity of lanosterol synthase in HEK293T cell lysates. Co-expression of viperin had no effect on the specific activity of squalene monooxygenase, but reduced its expression levels in the cells by approximately 30 %. Despite these inhibitory effects, co-expression of either LS or SM failed to reverse the viperin-induced depletion of cellular cholesterol levels in HEK293T cells. Our results establish a clear link between the down-regulation of cholesterol biosynthesis and viperin, although at this point the effect cannot be unambiguously attributed interactions between viperin and a specific biosynthetic enzyme.

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“…Various studies had previously linked viperin to the downregulation of cholesterol biosynthesis (39, 46,55), but the effect of viperin expression on cellular cholesterol biosynthesis had not been investigated.…”

Section: Viperin Expression Reduces Cholesterol Biosynthesismentioning

confidence: 99%

The antiviral enzyme viperin inhibits cholesterol biosynthesis

Grunkemeyer

Ghosh

Patel

et al. 2021

Journal of Biological Chemistry

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Human viperin catalyzes the modification of GPP and FPP potentially affecting cholesterol synthesis

Cited by 12 publications

References 40 publications

Reconstitution and substrate specificity for isopentenyl pyrophosphate of the antiviral radical SAM enzyme viperin

Reconstitution and substrate specificity for isopentenyl pyrophosphate of the antiviral radical SAM enzyme viperin

Viperin inhibits cholesterol biosynthesis and interacts with enzymes in the cholesterol biosynthetic pathway

The antiviral enzyme viperin inhibits cholesterol biosynthesis

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