Journal: Research
Article Title: Hypoxic Reprogramming of ACOX1-Driven HSP90AB1 Crotonylation Stabilizes Thioredoxin to Orchestrate Redox Homeostasis in Oral Squamous Cell Carcinoma
doi: 10.34133/research.1129
Figure Lengend Snippet: Hypoxia induces the site-specific crotonylation of heat shock protein 90 alpha family class B member 1 (HSP90AB1) at lysine 265 (K265) to regulate redox homeostasis in OSCC. (A) Volcano plot of crotonylation sites in CAL27 cells after 24 h of hypoxia versus normoxia. Sites are colored red for fold changes >1.5 and P < 0.05 and blue for fold changes <−1.5 and P < 0.05. (B and C) Subcellular localization analysis of (B) up-regulated and (C) down-regulated crotonylated proteins. (D) Immunoprecipitation (IP) of endogenous HSP90AB1 in CAL27/HSC3 cells under normoxia/hypoxia (24 h) and probing with a pan-Kcr antibody (IgG, immunoglobulin G; WCL, whole-cell lysate). (E) IP of Flag-HSP90AB1 in HEK293T cells under normoxia and hypoxia probed with a pan-Kcr antibody. (F) Crotonylation levels of Flag-HSP90AB1 in HEK293T cells treated with sodium crotonate (0 to 10 mM) under normoxia (24 h). (G) Domain structure of HSP90AB1 (NTD, N-terminal domain; MD, middle domain; CD, charged domain; CTD, C-terminal domain) and K265 mutation schematic (K, lysine; R, arginine; Q, glutamine). (H and I) IP of Flag-HSP90AB1 in HEK293T cells reconstituted with HSP90AB1 variants (wild type [WT], K265R, and K265Q) under normoxia/hypoxia (24 h) and probed with (H) pan-Kcr and (I) site-specific K265cr antibodies. (J) Representative confocal images of DCFH-DA staining in HSP90AB1-knockdown CAL27/HSC3 cells reconstituted with HSP90AB1 variants under normoxia/hypoxia (24 h) (200×, scale bars, 100 μm). NC, negative control; N, normoxia; H, hypoxia. (K) Quantification of DCFH-DA fluorescence intensity in HSP90AB1-knockdown CAL27/HSC3 cells reconstituted with HSP90AB1 variants under normoxia/hypoxia (24 h) (** P < 0.01 and *** P < 0.001, one-way ANOVA).
Article Snippet: The following primary antibodies were used: rabbit anti-β-actin (1:4,000; Proteintech, 20536-1-AP), rabbit anti-TXN (1:1,500; Abways, CY6679), rabbit anti-HIF-1α (1:1,500; Abways, CY5197), rabbit anti-HSP90AB1 (1:10,000; Abcam, ab203085), rabbit anti-pan-crotonyllysine (1:1,000; PTM Biolab, PTM-501), rabbit anti-Flag (1:5,000; Abways, AB0030), mouse anti-His (1:10,000; Proteintech, 66005-1-Ig), rabbit anti-HSP90AB1 K265cr (1:1,000; PTM Biolab), and rabbit anti-ACOX1 (1:4,000; Proteintech, 10957-1-AP).
Techniques: Immunoprecipitation, Mutagenesis, Staining, Knockdown, Negative Control, Fluorescence