Fig. 4: The TM domain and C-terminus are important for ORF3a-mediated blockade of autophagy.
From: The SARS-CoV-2 protein ORF3a inhibits fusion of autophagosomes with lysosomes
a ORF3a colocalized with lysosome. ORF3a-GFP was expressed in HeLa cells, and lysosomes were visualized by immunofluorescence with an anti-LAMP-1 antibody. Scale bars, 0.5 μm. b Schematic representation of ORF3a and the indicated truncated mutant used to determine the cellular localization and function of ORF3a in autophagy. c Fluorescence of GFP-tagged ORF3a and the indicated truncated mutants in HeLa cells. Scale bars, 0.25 μm. d ORF3a and the indicated truncated mutants were expressed in HeLa cells, and their effect on autophagy was analyzed by detecting the protein levels of p62 and LC3. e Schematic representation of the protein domains of ORF3a homologs in β-coronaviruses (SARS-CoV-2, SARS-CoV, and MERS-CoV). f Schematic representation of chimeras of the SARS-CoV-2 ORF3a TM domain with a C-terminus from an ORF3a homolog or the SARS-CoV-2 ORF3a C-terminus with a TM domain from an ORF3a homolog. g SARS-CoV-2 ORF3a TM + C-terminal truncated mutant or the indicated chimeras were expressed in HeLa cells, and their effect on autophagy was analyzed by measuring the protein levels of p62 and LC3-II.
