Fig. 3: Rab1a is a specific activator of VPS34 complex I.
From: Structural basis for VPS34 kinase activation by Rab1 and Rab5 on membranes
a Immunoblot of streptavidin precipitates from cells in which MitoID had been carried out for Rab1a WT, QL, and SN mutants (left) or Rab5 QL (right). Rab1a interacts specifically with components of complex I (VPS34, VPS15, Beclin 1, ATG14L) but not with the complex II-specific UVRAG. Rab5a shows only a weak interaction with the complex I-specific ATG14L. b Complex I was potently activated by membrane-attached Rab1a in a GTP-dependent manner. c No activation of complex II by either membrane-attached Rab1a–GTP or Rab1a–GDP was detected. b, c Micrographs: AF647-PX signals at the end of reactions. Scale bars: 5 μm. Bar graphs: initial rates of the reaction curves. d Lipid flotation assays showing complex I recruitment to Rab1a-decorated membranes in a GTP-dependent manner. Gel quantification is in Supplementary Fig. 2c. e Mapping Rab1a binding site on complex I by HDX-MS. Rab1a binding increases protection (coloured in cyan and blue) of the VPS34 C2 insertion (C2HH) and decreases protection (coloured yellow and red) of Beclin 1 CC2. Source data are provided as a Source Data file.
