scholarly journals Host autophagy machinery is diverted to the pathogen interface to mediate focal defense responses against the Irish potato famine pathogen

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Yasin F Dagdas ◽  
Pooja Pandey ◽  
Yasin Tumtas ◽  
Nattapong Sanguankiattichai ◽  
Khaoula Belhaj ◽  
...  
Keyword(s):  
Plant Immunity ◽  
Defense Responses ◽  
Effector Proteins ◽  
Plant Colonization ◽  
Effector Protein ◽  
Selective Autophagy ◽  
Host Membrane ◽  
Complex Functions ◽  
Potato Famine ◽  
Irish Potato Famine

During plant cell invasion, the oomycete Phytophthora infestans remains enveloped by host-derived membranes whose functional properties are poorly understood. P. infestans secretes a myriad of effector proteins through these interfaces for plant colonization. Recently we showed that the effector protein PexRD54 reprograms host-selective autophagy by antagonising antimicrobial-autophagy receptor Joka2/NBR1 for ATG8CL binding (Dagdas et al., 2016). Here, we show that during infection, ATG8CL/Joka2 labelled defense-related autophagosomes are diverted toward the perimicrobial host membrane to restrict pathogen growth. PexRD54 also localizes to autophagosomes across the perimicrobial membrane, consistent with the view that the pathogen remodels host-microbe interface by co-opting the host autophagy machinery. Furthermore, we show that the host-pathogen interface is a hotspot for autophagosome biogenesis. Notably, overexpression of the early autophagosome biogenesis protein ATG9 enhances plant immunity. Our results implicate selective autophagy in polarized immune responses of plants and point to more complex functions for autophagy than the widely known degradative roles.

scholarly journals Perturbation of host autophagy by the Irish potato famine pathogen

2014 ◽  
Vol 70 (a1) ◽  
pp. C826-C826
Author(s):  
Abbas Maqbool ◽  
Richard Richard ◽  
Tolga Bozkurt ◽  
Yasin Dagdas ◽  
Khaoula Belhai ◽  
...  
Keyword(s):  
Host Cell ◽  
Plant Cells ◽  
Irish Potato ◽  
Effector Proteins ◽  
Host Cells ◽  
Cell Physiology ◽  
Biochemical Basis ◽  
The Impact ◽  
Potato Famine ◽  
Irish Potato Famine

Autophagy is a catabolic process involving degradation of dysfunctional cytoplasmic components to ensure cellular survival under starvation conditions. The process involves formation of double-membrane vesicles called autophagosomes and delivery of the inner constituents to lytic compartments. It can also target invading pathogens, such as intracellular bacteria, for destruction and is thus implicated in innate immune pathways [1]. In response, certain mammalian pathogens deliver effector proteins into host cells that inhibit autophagy and contribute to enabling parasitic infection [2]. Pyhtophthora infestans, the Irish potato famine pathogen, is a causative agent of late blight disease in potato and tomato crops. It delivers a plethora of modular effector proteins into plant cells to promote infection. Once inside the cell, RXLR-type effector proteins engage with host cell proteins, to manipulate host cell physiology for the benefit of the pathogen. As plants lack an adaptive immune system, this provides a robust mechanism for pathogens to circumvent host defense. PexRD54 is an intracellular RXLR-type effector protein produced by P. infestans. PexRD54 interacts with potato homologues of autophagy protein ATG8 in plant cells. We have been investigating the structural and biochemical basis of the PexRD54/ATG8 interaction in vitro. We have purified PexRD54 and ATG8 independently and in complex from E. coli. Using protein/protein interaction studies we have shown that PexRD54 binds ATG8 with sub-micromolar affinity. We have also determined the structure of PexRD54 in the presence of ATG8. This crystal structure provides key insights into how the previously reported WY-fold of oomycete RXLR-type effectors [3] can be organized in multiple repeats. The structural data also provides insights into the interaction between PexRD54 and ATG8, suggesting further experiments to understand the impact of this interaction on host cell physiology and how this benefits the pathogen.

scholarly journals The Irish potato famine pathogen subverts host vesicle trafficking to channel starvation-induced autophagy to the pathogen interface

2020 ◽  
Author(s):  
Pooja Pandey ◽  
Alexandre Y Leary ◽  
Yasin Tümtas ◽  
Zachary Savage ◽  
Bayantes Dagvadorj ◽  
...  
Keyword(s):  
Small Gtpase ◽  
Effector Proteins ◽  
Host Cells ◽  
Irish Famine ◽  
Cellular Processes ◽  
Autophagy Pathway ◽  
Basal Immunity ◽  
Endomembrane Trafficking ◽  
Potato Famine ◽  
Irish Potato Famine

SummaryEukaryotic cells deploy autophagy to eliminate invading microbes. In turn, pathogens have evolved effector proteins to counteract antimicrobial autophagy. How and why adapted pathogens co-opt autophagy for their own benefit is poorly understood. The Irish famine pathogen Phythophthora infestans secretes the effector protein PexRD54 that selectively activates an unknown plant autophagy pathway, while antagonizing antimicrobial autophagy. Here we show that PexRD54 induces autophagosome formation by bridging small GTPase Rab8a-decorated vesicles with autophagic compartments labelled by the core autophagy protein ATG8CL. Rab8a is required for pathogen-triggered and starvation-induced but not antimicrobial autophagy, revealing that specific trafficking pathways underpin selective autophagy. We discovered that Rab8a contributes to basal immunity against P. infestans, but PexRD54 diverts a sub-population of Rab8a vesicles to lipid droplets that associate with autophagosomes. These are then diverted towards pathogen feeding structures that are accommodated within the host cells. We propose that PexRD54 mimics starvation-induced autophagy by channeling host endomembrane trafficking towards the pathogen interface possibly to acquire nutrients. This work reveals that effectors can interconnect independent host compartments to stimulate complex cellular processes that benefit the pathogen.Graphical abstract

scholarly journals Host autophagosomes are diverted to a plant-pathogen interface

2017 ◽  
Author(s):  
Yasin F Dagdas ◽  
Pooja Pandey ◽  
Nattapong Sanguankiattichai ◽  
Yasin Tumtas ◽  
Khaoula Belhaj ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Plant Pathogen ◽  
Plant Pathogens ◽  
Irish Potato ◽  
Host Protein ◽  
Host Cells ◽  
Autophagosome Formation ◽  
Selective Autophagy ◽  
Potato Famine ◽  
Irish Potato Famine

AbstractFilamentous plant pathogens and symbionts invade their host cells but remain enveloped by host-derived membranes. The mechanisms underlying the biogenesis and functions of these host-microbe interfaces are poorly understood. Recently, we showed that PexRD54, an effector from the Irish potato famine pathogen Phytophthora infestans, binds host protein ATG8CL to stimulate autophagosome formation and deplete the selective autophagy receptor Joka2 from ATG8CL complexes. Here, we show that during P. infestans infection, ATG8CL autophagosomes are diverted to the pathogen interface. Our findings are consistent with the view that the pathogen coopts host selective autophagy for its own benefit.

scholarly journals Structural Basis of Host Autophagy-related Protein 8 (ATG8) Binding by the Irish Potato Famine Pathogen Effector Protein PexRD54

2016 ◽  
Vol 291 (38) ◽  
pp. 20270-20282 ◽  
Author(s):  
Abbas Maqbool ◽  
Richard K. Hughes ◽  
Yasin F. Dagdas ◽  
Nicholas Tregidgo ◽  
Erin Zess ◽  
...  
Keyword(s):  
Irish Potato ◽  
Structural Basis ◽  
Effector Protein ◽  
Related Protein ◽  
Pathogen Effector ◽  
Potato Famine ◽  
Irish Potato Famine

scholarly journals The EspF Effector, a Bacterial Pathogen's Swiss Army Knife

2010 ◽  
Vol 78 (11) ◽  
pp. 4445-4453 ◽  
Author(s):  
Ashleigh Holmes ◽  
Sabrina Mühlen ◽  
Andrew J. Roe ◽  
Paul Dean
Keyword(s):  
Escherichia Coli ◽  
Mitochondrial Dysfunction ◽  
Cell Invasion ◽  
Intermediate Filament ◽  
Effector Proteins ◽  
Epithelial Barrier ◽  
Effector Protein ◽  
Cellular Processes ◽  
Molecular Events ◽  
Host Membrane

ABSTRACT Central to the pathogenesis of many bacterial pathogens is the ability to deliver effector proteins directly into the cells of their eukaryotic host. EspF is one of many effector proteins exclusive to the attaching and effacing pathogen family that includes enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli. Work in recent years has revealed EspF to be one of the most multifunctional effector proteins known, with defined roles in several host cellular processes, including disruption of the epithelial barrier, antiphagocytosis, microvillus effacement, host membrane remodelling, modulation of the cytoskeleton, targeting and disruption of the nucleolus, intermediate filament disruption, cell invasion, mitochondrial dysfunction, apoptosis, and inhibition of several important epithelial transporters. Surprisingly, despite this high number of functions, EspF is a relatively small effector protein, and recent work has begun to decipher the molecular events that underlie its multifunctionality. This review focuses on the activities of EspF within the host cell and discusses recent findings and molecular insights relating to the virulence functions of this fascinating bacterial effector.

scholarly journals Legionella pneumophila LegC7 effector protein drives aberrant ER:endosome fusion in yeast

2020 ◽  
Author(s):  
Nathan K. Glueck ◽  
Kevin M. O’Brien ◽  
Vincent J. Starai
Keyword(s):  
Membrane Trafficking ◽  
Legionella Pneumophila ◽  
Molecular Mechanisms ◽  
Bacterial Pathogen ◽  
Severe Form ◽  
Effector Proteins ◽  
Effector Protein ◽  
Host Membrane ◽  
Membrane Tethering

AbstractLegionella pneumophila is a facultative intracellular bacterial pathogen, causing the severe form of pneumonia known as Legionnaires’ disease. Legionella actively alters host organelle trafficking through the activities of ‘effector’ proteins secreted via a TypeIVB secretion system, in order to construct the bacteria-laden Legionella-containing vacuole (LCV) and prevent lysosomal degradation. The LCV is derived from membrane derived from host ER, secretory vesicles, and phagosomes, although the precise molecular mechanisms that drive its synthesis remain poorly understood. In an effort to characterize the in vivo activity of the LegC7/YlfA SNARE-like effector protein from Legionella in the context of eukaryotic membrane trafficking in yeast, we find that LegC7 interacts with the Emp46p/Emp47p ER-to-Golgi glycoprotein cargo adapter complex, alters ER morphology, and induces aberrant ER:endosome fusion, as measured by visualization of ER cargo degradation, reconstitution of split-GFP proteins, and enhanced oxidation of the ER lumen. LegC7-dependent toxicity, disruption of ER morphology, and ER:endosome fusion events were dependent upon endosomal VPS class C tethering complexes and the endosomal t-SNARE, Pep12p. This work establishes a model in which LegC7 functions to recruit host ER material to the bacterial phagosome during infection by inducing membrane fusion, potentially through interaction with host membrane tethering complexes and/or cargo adapters.

scholarly journals A Valsa mali Effector Protein 1 Targets Apple (Malus domestica) Pathogenesis-Related 10 Protein to Promote Virulence

2021 ◽  
Vol 12 ◽  
Author(s):  
Weidong Wang ◽  
Jiajun Nie ◽  
Luqiong Lv ◽  
Wan Gong ◽  
Shuaile Wang ◽  
...  
Keyword(s):  
Malus Domestica ◽  
Plant Immunity ◽  
Effector Proteins ◽  
Parasitic Fungus ◽  
Effector Protein ◽  
Positive Role ◽  
Host Immune Responses ◽  
Pathogenesis Related ◽  
Valsa Mali

To successfully colonize the plants, the pathogenic microbes secrete a mass of effector proteins which manipulate host immunity. Apple valsa canker is a destructive disease caused by the weakly parasitic fungus Valsa mali. A previous study indicated that the V. mali effector protein 1 (VmEP1) is an essential virulence factor. However, the pathogenic mechanism of VmEP1 in V. mali remains poorly understood. In this study, we found that the apple (Malus domestica) pathogenesis-related 10 proteins (MdPR10) are the virulence target of VmEP1 using a yeast two-hybrid screening. By bimolecular fluorescence (BiFC) and coimmunoprecipitation (Co-IP), we confirmed that the VmEP1 interacts with MdPR10 in vivo. Silencing of MdPR10 notably enhanced the V. mali infection, and overexpression of MdPR10 markedly reduced its infection, which corroborates its positive role in plant immunity against V. mali. Furthermore, we showed that the co-expression of VmEP1 with MdPR10 compromised the MdPR10-mediated resistance to V. mali. Taken together, our results revealed a mechanism by which a V. mali effector protein suppresses the host immune responses by interfering with the MdPR10-mediated resistance to V. mali during the infection.

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