SUMMARYLysine acetylation is a major posttranslational modification involved in
a broad array of physiological functions. Here, we provide an organ-wide map of
lysine acetylation sites from 16 rat tissues analyzed by high-resolution tandem
mass spectrometry. We quantify 15,474 modification sites on 4,541 proteins and
provide the data set as a web-based database. We demonstrate that lysine
acetylation displays site-specific sequence motifs that diverge between cellular
compartments, with a significant fraction of nuclear sites conforming to the
consensus motifs G-AcK and AcK-P. Our data set reveals that the subcellular
acetylation distribution is tissue-type dependent and that acetylation targets
tissue-specific pathways involved in fundamental physiological processes. We
compare lysine acetylation patterns for rat as well as human skeletal muscle
biopsies and demonstrate its general involvement in muscle contraction.
Furthermore, we illustrate that acetylation of fructose-bisphosphate aldolase
and glycerol-3-phosphate dehydrogenase serves as a cellular mechanism to switch
off enzymatic activity.
Binding assays are increasingly used as a screening method for protein kinase inhibitors; however, as yet only a weak correlation with enzymatic activity-based assays has been demonstrated. We show that the correlation between the two types of assays can be improved using more precise screening conditions. Furthermore a marked improvement in the correlation was found by using kinase constructs containing the catalytic domain in presence of additional domains or subunits.
Aims/hypothesis Histone deacetylases (HDACs) are promising pharmacological targets in cancer and autoimmune diseases. All 11 classical HDACs (HDAC1-11) are found in the pancreatic beta cell, and HDAC inhibitors (HDACi) protect beta cells from inflammatory insults. We investigated which HDACs mediate inflammatory beta cell damage and how the islet content of these HDACs is regulated in recent-onset type 1 diabetes. Methods The rat beta cell line INS-1 and dispersed primary islets from rats, either wild type or HDAC1-3 deficient, were exposed to cytokines and HDACi. Molecular mechanisms were investigated using real-time PCR, chromatin immunoprecipitation and ELISA assays. Pancreases from healthy children and children with type 1 diabetes were assessed using immunohistochemistry and immunofluorescence. Results Screening of 19 compounds with different HDAC selectivity revealed that inhibitors of HDAC1, -2 and -3 rescued INS-1 cells from inflammatory damage. Small hairpin RNAs against HDAC1 and -3, but not HDAC2, reduced pro-inflammatory cytokine-induced beta cell apoptosis in INS-1 and primary rat islets. The protective properties of specific HDAC knock-down correlated with attenuated cytokine-induced iNos expression but not with altered expression of the proinflammatory mediators Il1α, Il1β, Tnfα or Cxcl2. HDAC3 knock-down reduced nuclear factor κB binding to the iNos promoter and HDAC1 knock-down restored insulin secretion. In pancreatic sections from children with type 1 diabetes of recent onset, HDAC1 was upregulated in beta cells whereas HDAC2 and -3 were downregulated in comparison with five paediatric controls. Conclusions/interpretation These data demonstrate nonredundant functions of islet class I HDACs and suggest that targeting HDAC1 and HDAC3 would provide optimal protection of beta cell mass and function in clinical islet transplantation and recent-onset type 1 diabetic patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.