Fig. 5: Chaperone condensates function as folding factories.
From: A multichaperone condensate enhances protein folding in the endoplasmic reticulum
a, Co-localization of endogenous PDIA6 and overexpressed proinsulin–myc in fixed HeLa cells. Arrowheads exemplarily indicate the position of condensates. b, Co-localization of overexpressed PDIA6–GFP and proinsulin–myc in fixed HeLa cells. c, Secretion levels of insulin (medium), and expression levels of PDIA6 and α-tubulin (lysate) in HeLa cells transfected with proinsulin, proinsulin + PDIA6–GFP WT or proinsulin + PDIA6–GFP 5× linker mutant. Proinsulin was not detectable in the lysate. d, Secretion levels of insulin (medium) as well as expression levels of PDIA6, proinsulin and α-tubulin (lysate) in INS-1 cells transfected with mock, PDIA6–GFP WT or PDIA6–GFP 5× linker mutant. In c and d, representative blots from three independent replicates. e, Fold increase in spliced XBP1 (sXBP1) in HeLa cells transfected with PDIA6 WT or 5× linker mutant relative to untransfected cells, determined using quantitative PCR with reverse transcription (P = 0.00092). f, Flow cytometry-based cell aggresome analysis of HeLa cells transfected with PDIA6–GFP WT or PDIA6–GFP 5× linker mutant, detected by PROTEOSTAT aggresome dye (P = 0.007). Gating strategy summarized in Supplementary Fig. 2. g, Half recovery time of mApple–Sec61 in HeLa cells co-transfected with PDIA6–GFP WT or PDIA6–GFP 5× linker mutant. Data from three independent experiments were fitted individually and averaged (P = 0.003). In e–g, data are the mean ± s.d.; n = 3 independent biological experiments per condition; two-sided Student’s t-test. h, Model of PDIA6 chaperones condensates functioning as folding factories (details in text). **P < 0.01, ***P < 0.001. Unprocessed blots are available.
