African swine fever virus I10L protein inhibits autolysosome formation by disrupting RAB7-HOPS complex-dependent...

Macroautophagy/autophagy serves as a crucial cellular defense mechanism against invading pathogens. However, viruses have evolved diverse strategies to evade or even exploit autophagy for their own replication. In this study, we reveal that the African swine fever virus (ASFV)-encoded I10L protein suppresses autophagy by blocking autophagosome-lysosome fusion. Mechanistically, I10L directly interacts with the endolysosomal RAB GTPase RAB7, a master regulator of vesicle docking at late endosomes and lysosomes. This interaction competitively prevents RAB7 from binding to VPS39, a core component of the homotypic fusion and vacuole protein sorting (HOPS) complex. Consequently, I10L disrupts the assembly of the STX17-SNAP29-VAMP8 SNARE complex, which is essential for autophagosome-lysosome fusion. ASFV infection thus induces autophagosome accumulation, whereas I10L deletion reverses this effect and attenuates viral replication in primary macrophages. Our findings uncover a novel immune evasion strategy by which ASFV subverts lysosomal degradation through RAB7-HOPS axis manipulation, providing both mechanistic insights into viral pathogenicity and potential therapeutic targets for antiviral development.Abbreviations: ASFV: African swine fever virus; GEF: guanine nucleotide exchange factor; GFP: green fluorescent protein; HOPS: homotypic fusion and vacuole protein sorting; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PAMs: primary alveolar macrophages; RAB7: RAB7, member RAS oncogene family; siRNA: small interfering RNA; SNAP29: synaptosome associated protein 29; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TM: transmembrane domain; VAMP8: vesicle associated membrane protein 8; VPS39: VPS39 subunit of HOPS complex; VPS41: VPS41 subunit of HOPS complex; YKT6: YKT6 vesicular SNARE protein.