Dataset Information

ATG9A shapes the forming autophagosome through Arfaptin 2 and phosphatidylinositol 4-kinase IIIβ.

ABSTRACT: ATG9A is a multispanning membrane protein essential for autophagy. Normally resident in Golgi membranes and endosomes, during amino acid starvation, ATG9A traffics to sites of autophagosome formation. ATG9A is not incorporated into autophagosomes but is proposed to supply so-far-unidentified proteins and lipids to the autophagosome. To address this function of ATG9A, a quantitative analysis of ATG9A-positive compartments immunoisolated from amino acid-starved cells was performed. These ATG9A vesicles are depleted of Golgi proteins and enriched in BAR-domain containing proteins, Arfaptins, and phosphoinositide-metabolizing enzymes. Arfaptin2 regulates the starvation-dependent distribution of ATG9A vesicles, and these ATG9A vesicles deliver the PI4-kinase, PI4KIIIβ, to the autophagosome initiation site. PI4KIIIβ interacts with ATG9A and ATG13 to control PI4P production at the initiation membrane site and the autophagic response. PI4KIIIβ and PI4P likely function by recruiting the ULK1/2 initiation kinase complex subunit ATG13 to nascent autophagosomes.

SUBMITTER: Judith D

PROVIDER: S-EPMC6504893 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

ATG9A shapes the forming autophagosome through Arfaptin 2 and phosphatidylinositol 4-kinase IIIβ.

Judith Delphine D Jefferies Harold B J HBJ Boeing Stefan S Frith David D Snijders Ambrosius P AP Tooze Sharon A SA

The Journal of cell biology 20190327 5

ATG9A is a multispanning membrane protein essential for autophagy. Normally resident in Golgi membranes and endosomes, during amino acid starvation, ATG9A traffics to sites of autophagosome formation. ATG9A is not incorporated into autophagosomes but is proposed to supply so-far-unidentified proteins and lipids to the autophagosome. To address this function of ATG9A, a quantitative analysis of ATG9A-positive compartments immunoisolated from amino acid-starved cells was performed. These ATG9A ves ...[more]

PMID: 30917996

Similar Datasets

Project description:Like other enteroviruses, enterovirus 71 (EV71) relies on phosphatidylinositol 4-kinase IIIβ (PI4KB) for genome RNA replication. However, how PI4KB is recruited to the genome replication sites of EV71 remains elusive. Recently, we reported that a host factor, ACBD3, is needed for EV71 replication by interacting with viral 3A protein. Here, we show that ACBD3 is required for the recruitment of PI4KB to RNA replication sites. Overexpression of viral 3A or EV71 infection stimulates the interaction of PI4KB and ACBD3. Consistently, EV71 infection induces the production of phosphatidylinositol-4-phosphate (PI4P). Furthermore, PI4KB, ACBD3, and 3A are all localized to the viral-RNA replication sites. Accordingly, PI4KB or ACBD3 depletion by small interfering RNA (siRNA) leads to a reduction in PI4P production after EV71 infection. I44A or H54Y substitution in 3A interrupts the stimulation of PI4KB and ACBD3. Further analysis suggests that stimulation of ACBD3-PI4KB interaction is also important for the replication of enterovirus 68 but disadvantageous to human rhinovirus 16. These results reveal a mechanism of enterovirus replication that involves a selective strategy for recruitment of PI4KB to the RNA replication sites.IMPORTANCE Enterovirus 71, like other human enteroviruses, replicates its genome within host cells, where viral proteins efficiently utilize cellular machineries. While multiple factors are involved, it is largely unclear how viral replication is controlled. We show that the 3A protein of enterovirus 71 recruits an enzyme, phosphatidylinositol 4-kinase IIIβ, by interacting with ACBD3, which alters cellular membranes through the production of a lipid, PI4P. Consequently, the viral and host proteins form a large complex that is necessary for RNA synthesis at replication sites. Notably, PI4KB-ACBD3 interaction also differentially mediates the replication of enterovirus 68 and rhinovirus 16. These results provide new insight into the molecular network of enterovirus replication.

Project description:Enteroviruses are one of the most abundant viruses causing mild to serious acute infections in humans and also contributing to chronic diseases like type 1 diabetes. Presently, there are no approved antiviral drugs against enteroviruses. Here, we studied the potency of vemurafenib, an FDA-approved RAF kinase inhibitor for treating BRAFV600E mutant-related melanoma, as an antiviral against enteroviruses. We showed that vemurafenib prevented enterovirus translation and replication at low micromolar dosage in an RAF/MEK/ERK-independent manner. Vemurafenib was effective against group A, B, and C enteroviruses, as well as rhinovirus, but not parechovirus or more remote viruses such as Semliki Forest virus, adenovirus, and respiratory syncytial virus. The inhibitory effect was related to a cellular phosphatidylinositol 4-kinase type IIIβ (PI4KB), which has been shown to be important in the formation of enteroviral replication organelles. Vemurafenib prevented infection efficiently in acute cell models, eradicated infection in a chronic cell model, and lowered virus amounts in pancreas and heart in an acute mouse model. Altogether, instead of acting through the RAF/MEK/ERK pathway, vemurafenib affects the cellular PI4KB and, hence, enterovirus replication, opening new possibilities to evaluate further the potential of vemurafenib as a repurposed drug in clinical care. IMPORTANCE Despite the prevalence and medical threat of enteroviruses, presently, there are no antivirals against them. Here, we show that vemurafenib, an FDA-approved RAF kinase inhibitor for treating BRAFV600E mutant-related melanoma, prevents enterovirus translation and replication. Vemurafenib shows efficacy against group A, B, and C enteroviruses, as well as rhinovirus, but not parechovirus or more remote viruses such as Semliki Forest virus, adenovirus, and respiratory syncytial virus. The inhibitory effect acts through cellular phosphatidylinositol 4-kinase type IIIβ (PI4KB), which has been shown to be important in the formation of enteroviral replication organelles. Vemurafenib prevents infection efficiently in acute cell models, eradicates infection in a chronic cell model, and lowers virus amounts in pancreas and heart in an acute mouse model. Our findings open new possibilities to develop drugs against enteroviruses and give hope for repurposing vemurafenib as an antiviral drug against enteroviruses.

Dataset Information

ATG9A shapes the forming autophagosome through Arfaptin 2 and phosphatidylinositol 4-kinase IIIβ.

Publications

ATG9A shapes the forming autophagosome through Arfaptin 2 and phosphatidylinositol 4-kinase IIIβ.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets