α tbk1

HEK293T, HeLa, or MEF cells were grown in chamber slides (Thermo Fisher), or on cover slips (Chemglass) in 24-well plates, and transfected and/or infected as indicated. Cells were fixed with 4% (w/v) paraformaldehyde (PFA, Santa Cruz) for 20 min, permeabilized with 0.5% (v/v) Triton-X-100 in PBS, and then blocked with 10% (v/v) goat serum or 1% milk powder in PBS for 1 h. For immunostaining, α-TRIM23 (1:200, ab97291, Abcam), α-LC3 (1:400, Novus Biologicals), α-phospho-S172-TBK1 (1:400, 5483, Cell Signaling), α-TBK1 (1:400, #3013, Cell Signaling), α-TRIM23 (1:100, clone C-1, sc-393923, Santa Cruz), α-FLAG (1:400, M2, Sigma), α-p62 (1:400, PROGEN Biotechnik), α-LAMP1 (1:400, H4A3, Developmental Studies Hybridoma Bank), α-V5 (1:500, R960-25, Life Technologies), α-myc (1:400, 9B11, Cell Signaling) and α-ATG16 (1:200, A7356, Sigma) were used, followed by incubation with secondary antibodies conjugated to Alexa Fluor 488, Alexa Fluor 555, Alexa Fluor 594, Alexa Fluor 633, or Alexa Fluor 647 (all 1:400, Life Technologies). Cells were mounted in DAPI-containing Vectashield (Vector Labs) to co-stain nuclei. All laser scanning images were acquired on an Olympus IX8I confocal microscope or on a Leica SP8 confocal microscope. Cytoplasmic GFP-LC3B puncta in HeLa, HEK293T and MEF cells were manually counted for 30 or 50 randomly selected cells.

For Western blotting and immunofluorescence microscopy, the following antibodies were used: α-cGAS (MB21D1) (HPA031700; Sigma), α-GFP (#11814460001; Roche), α-FLAG (M2) (F3165; Sigma), α-OASL (ab191701; Abcam), α-tubulin (T6199; Sigma-Aldrich), α-STING (TMEM173) (ab92605; Abcam), α-Phosph.-TBK1 (Ser172) (#5483; Cell Signal Technology), α-TBK1 (#3013; Cell Signaling Technology), α--IRF3 (#4302; Cell Signaling Technology), α-phospho-IRF3 (Ser396) (#4947; Cell Signaling Technology), α-ICP0 (H1A027–100; Virusys Corporation), α-PARP (#9542; Cell Signaling Technology), anti-ASCC3 (ab168810; Abcam), anti-OAS2 (MAB1925; R & D Systems). The secondary antibodies used for immunofluorescence microscopy and the LI-COR Odyssey Western blotting imaging system were conjugated with Alexa Fluor fluorophores (Life Technologies).