AKT1 is classically known as a serine/threonine kinase controlling cell survival and proliferation, yet its kinase-independent functions remain poorly understood. Here we show that recognition of dsRNA viral capsids by membrane-associated HSP90AA1 disrupts the HSP90-AKT1 interaction, inducing AKT1 dephosphorylation at Thr308. This non-phosphorylated AKT1 acts as a scaffold to recruit PDPK1 and SQSTM1, enabling PDPK1-dependent phosphorylation of SQSTM1 at Ser349 and selective loading of viral capsids into LC3C-positive phagophores for degradation. An IBDV capsid mutant defective in SQSTM1 binding escapes this pathway. In vivo, expression of non-phosphorylatable AKT1 suppresses rotavirus replication in a SQSTM1-dependent manner. These findings identify an HSP90-initiated, kinase-independent AKT1 signaling axis that licenses antiviral macroautophagy/autophagy.Abbreviations: AKT1: AKT serine/threonine kinase 1; CQ: chloroquine; dpi: days post-infection; dsRNA: double-stranded RNA; GABARAPL1: GABA type A receptor associated protein like 1; hpi: hour post infection; HSP90AA1: heat shock protein 90 alpha family class A member 1; IBDV: infectious bursal disease virus; KO: knockout; LIR: LC3-interacting region; MAP1LC3C/LC3C: microtubule associated protein 1 light chain 3 gamma; MOI: multiplicity of infection; PDPK1: 3-phosphoinositide dependent protein kinase 1; rVP2: recombinant His-tagged VP2; rVP4: recombinant His-tagged VP4; RV: rotavirus; SQSTM1: sequestosome 1; WT: wild-type.
Keywords: AKT1; ATG8 family; LC3C; SQSTM1; dsRNA virus.