Fig 1: Regulation of Ksor by class I HDACs.(A) Schematic representation of HDAC-mediated Ksor and desorbylation. (B) Chemical inhibitor screening with extracted histones to identify a major class of HDACs that remove histone lysine sorbylation in cells. 293T cells were treated with 10 mM sorbate overnight. Sorbate-containing media were replaced with fresh media with or without various chemical inhibitors for 5 hours targeting different classes of HDACs including TSA (1 μM, lane 4), sodium butyrate (10 mM, lane 5), nicotinamide (25 mM, lane 6), UF010 (2 μM, lane 7), TMP195 (1 μM, lane 8), SIS17 (1 μM, lane 9), and MS275 (5 μM, lane 10) (C) Enzymatic assay and Western blot analysis demonstrating the in vitro desorbylase activities of class I HDACs (HDAC1-3) with recombinant enzymes and extracted histones from 293T cells treated with or without 10 mM sorbate and 40 mM sodium butyrate for 24 hours. (D) Western blotting analysis shows that HDAC inhibitor MS275 treatment dose-dependently inhibited Ksor in the presence of sorbate. 293T cells were treated with various concentrations of MS275 first for 30 min followed by the addition of potassium sorbate (2 mM) for the co-treatment of 6 hours before cell harvesting. (E) Enzymatic assay and Western blotting analysis demonstrating the in vitro sorbyltransferase activities of class I HDACs (HDAC1-3) with recombinant enzymes and extracted histones from regular 293T cells with or without sorbate. (F) siRNA knockdown and Western blot analysis demonstrating the endogenous activities of class I HDACs (HDAC1-3) in mediating global Ksor. SiRNAs targeting HDAC1, HDAC2, or HDAC3 were pooled and transfected to 293T cells for overnight incubation. Media were then replaced with fresh media with or without 10 mM sorbate treatment for overnight. Created in BioRender (Y. Chen, 2025; https://BioRender.com/a34b274, https://BioRender.com/b79o565, https://BioRender.com/r21b608, and https://BioRender.com/n20b369).