Abstract
Autophagy is an essential degradation pathway that assists eukaryote survival under multiple stress conditions. Autophagosomes engulfing cargoes accomplish degradation only when they have matured through fusing with lysosomes or vacuoles. However, the molecular machinery mediating autophagosome maturation in plants remains unknown. Using the combined approaches of mass spectrometry, biochemistry, reverse genetics and microscopy, we uncover that UVRAG, a subunit of the class III phosphatidylinositol 3-kinase complexes in Nicotiana benthamiana, plays an essential role in autophagsome maturation via ATG14-assisted recruitment to autophagosomes and by facilitating RAB7 activation. An interaction between N. benthamiana UVRAG and ATG14 was observed in vitro and in vivo, which strikingly differed from their mutually exclusive appearance in different PI3KC3 complexes in yeast and mammals. This interaction increased the localisation of UVRAG on autophagosomes and enabled the convergence of autophagic and late endosomal structures, where they contributed to fusions between these two types of organelles by recruiting the essential membrane fusion factors RAB7 GTPase and the homotypic fusion and protein sorting (HOPS) complex. In addition, we uncovered a joint contribution of ATG14 and UVRAG to geminiviral infection, beyond autophagy. Our study provides insights into the mechanisms of autophagosome maturation in plants and expands the understanding of organisations and roles of the PI3KC3 complexes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.