RESUMO
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.
Assuntos
Autofagia/genética , Interações Hospedeiro-Patógeno , Phytophthora infestans/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Solanum tuberosum/genética , ATPases Associadas a Diversas Atividades Celulares/genética , ATPases Associadas a Diversas Atividades Celulares/imunologia , Autofagossomos/imunologia , Autofagossomos/parasitologia , Autofagia/imunologia , Família da Proteína 8 Relacionada à Autofagia/genética , Família da Proteína 8 Relacionada à Autofagia/imunologia , Proteínas de Transporte/genética , Proteínas de Transporte/imunologia , Regulação da Expressão Gênica , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Phytophthora infestans/crescimento & desenvolvimento , Phytophthora infestans/patogenicidade , Células Vegetais/imunologia , Células Vegetais/parasitologia , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Imunidade Vegetal/genética , Proteínas de Plantas/imunologia , Ligação Proteica , Transdução de Sinais , Solanum tuberosum/imunologia , Solanum tuberosum/parasitologiaRESUMO
A simple and effective strategy was developed to enrich ubiquitinated proteins (UPs) from cancer cell lysate using the α-Al2O3 nanoparticles covalently linked with ubiquitin binding protein (Vx3) (denoted as α-Al2O3-Vx3) via a chemical linker. The functionalized α-Al2O3-Vx3 showed long-term stability and high efficiency for the enrichment of UPs from cancer cell lysates. Flow cytometry analysis results indicated dendritic cells (DCs) could more effectively phagocytize the covalently linked α-Al2O3-Vx3-UPs than the physical mixture of α-Al2O3 and Vx3-UPs (α-Al2O3/Vx3-UPs). Laser confocal microscopy images revealed that α-Al2O3-Vx3-UPs localized within the autophagosome of DCs, which then cross-presented α-Al2O3-Vx3-UPs to CD8+ T cells in an autophagosome-related cross-presentation pathway. Furthermore, α-Al2O3-Vx3-UPs enhanced more potent antitumor immune response and antitumor efficacy than α-Al2O3/cell lysate or α-Al2O3/Vx3-UPs. This work highlights the potential of using the Vx3 covalently linked α-Al2O3 as a simple and effective platform to enrich UPs from cancer cells for the development of highly efficient therapeutic cancer vaccines.