Extended Data Fig. 3 |. SREBP2 trafficking primes STING signalling in Npc1^KO cells independently of its transcriptional activity.

a, Diagram showing mechanisms of action for HP-β-CD and triparanol on cholesterol synthesis and SREBP2 activation. HP-β-CD promotes the egress of lysosomal cholesterol to the ER, thus limiting SREBP2 trafficking and activation in Npc1^KO cells. Triparanol inhibits the biochemical conversion of desmosterol into cholesterol, thus promoting SREBP2 trafficking and activation in wild-type cells. b, c, qRT–PCR analysis of cholesterol-synthesis genes (b) and ISGs (c) in Npc1^WT and Npc1^KO MEFs mock-treated or treated with HP-β-CD (0.3 mM) overnight (n = 3). d, e, qRT–PCR analysis of mock-, DMXAA- (50 μg ml⁻¹, 2 h) or poly(I:C)- (1 μg ml⁻¹, 2 h) induced expression of cholesterol-synthesis genes (d) and ISGs (e) with mock- or HP-β-CD treatment (0.3 mM, 8 h) in Npc1^WT MEFs (n = 3). f, qRT–PCR analysis of the baseline expression of ISGs in Npc1^WT and Npc1^KO MEFs transfected with siCtrl or siSrebf2 for 48 h (n = 3). g, Immunoblot analysis of the indicated proteins (left) in Npc1^WT, Npc1^KO, Npc1^KOSrebf2^KD and Npc1^KOSrebf2^KD MEFs reconstituted with SREBP2 wild type (FL) or transcription-inactive mutants (L511A/S512A, ΔbHLH). h, i, qRT–PCR analysis of the expression of cholesterol-synthesis genes (h) and ISGs (i) in Npc1^WT, Npc1^KO, Npc1^KOSrebf2^KD and Npc1^KOSrebf2^KD MEFs reconstituted with SREBP2 wild type (FL) or transcription-inactive mutants (L511A/S512A, ΔbHLH) (n = 3). b–f, h, i, Data are mean ± s.d. Unpaired two-tailed Student’s t-test. NS, not significant. Data are representative of at least two independent experiments.