Enhanced HSP70 lysine methylation promotes proliferation of cancer cells through activation of Aurora kinase B. Nat Commun 18(3):1072

1] Laboratory of Molecular Medicine, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan. [2].
Nature Communications (Impact Factor: 11.47). 09/2012; 3:1072. DOI: 10.1038/ncomms2074
Source: PubMed


Although heat-shock protein 70 (HSP70), an evolutionarily highly conserved molecular chaperone, is known to be post-translationally modified in various ways such as phosphorylation, ubiquitination and glycosylation, physiological significance of lysine methylation has never been elucidated. Here we identify dimethylation of HSP70 at Lys-561 by SETD1A. Enhanced HSP70 methylation was detected in various types of human cancer by immunohistochemical analysis, although the methylation was barely detectable in corresponding non-neoplastic tissues. Interestingly, methylated HSP70 predominantly localizes to the nucleus of cancer cells, whereas most of the HSP70 protein locates to the cytoplasm. Nuclear HSP70 directly interacts with Aurora kinase B (AURKB) in a methylation-dependent manner and promotes AURKB activity in vitro and in vivo. We also find that methylated HSP70 has a growth-promoting effect in cancer cells. Our findings demonstrate a crucial role of HSP70 methylation in human carcinogenesis.

Download full-text


Available from: Ryuji Hamamoto, Jan 01, 2014
  • Source
    • "After boiling in sample buffer, the samples were subjected to SDS-PAGE, and visualized by fluorography [34] "
    [Show abstract] [Hide abstract]
    ABSTRACT: Poly(ADP-ribose) polymerase-1 (PARP1) catalyzes the poly(ADP-ribosyl)ation of protein acceptors using NAD(+) as the substrate is now considered as an important target for development of anticancer therapy. PARP1 is known to be post-translationally modified in various ways including phosphorylation and ubiquitination, but the physiological role of PARP1 methylation is not well understood. Herein we demonstrated that the histone methyltransferase SMYD2, which plays critical roles in human carcinogenesis, mono-methylated PARP1. We confirmed lysine 528 to be a target of SMYD2-dependent PARP1 methylation by LC-MS/MS and Edman Degradation analyses. Importantly, methylated PARP1 revealed enhanced poly(ADP-ribose) formation after oxidative stress, and positively regulated the poly(ADP-ribosyl)ation activity of PARP1. Hence, our study unveils a novel mechanism of PARP1 in human cancer through its methylation by SMYD2.
    Full-text · Article · Apr 2014 · Neoplasia (New York, N.Y.)
  • Source
    • "The K120 monomethylation status of histone H2B in clinical tissues were examined by immunohistochemical analysis [1] [17]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The histone methyltransferase enhancer of zeste 2 (EZH2) is known to be a polycomb protein homologous to Drosophila enhancer of zeste and catalyzes the addition of methyl groups to histone H3 at lysine 27 (H3K27). We previously reported that EZH2 was overexpressed in various types of cancer and plays a crucial role in the cell cycle regulation of cancer cells. In the present study, we demonstrated that EZH2 has the function to monomethylate lysine 120 on histone H2B (H2BK120). EZH2-dependent H2BK120 methylation in cancer cells was confirmed with an H2BK120 methylation-specific antibody. Overexpression of EZH2 significantly attenuated the ubiquitination of H2BK120, a key posttranslational modification of histones for transcriptional regulation. Concordantly, knockdown of EZH2 increased the ubiquitination level of H2BK120, suggesting that the methylation of H2BK120 by EZH2 may competitively inhibit the ubiquitination of H2BK120. Subsequent chromatin immunoprecipitation-Seq and microarray analyses identified downstream candidate genes regulated by EZH2 through the methylation of H2BK120. This is the first report to describe a novel substrate of EZH2, H2BK120, unveiling a new aspect of EZH2 functions in human carcinogenesis.
    Full-text · Article · Nov 2013 · Neoplasia (New York, N.Y.)
  • Source
    • "In the case of Hsp70 chaperones, one of these enzymes, METTL21A, was found to trimethylate multiple Hsp70 isoforms on a conserved lysine (K561). Another group confirmed that K561 of Hsp70 was indeed the target of methylation, although in this instance the residue appeared to be dimethylated and the enzyme responsible for this mark was proposed to be SETD1A [66]. It was further demonstrated that the modification resulted in translocation of the chaperone from the cytoplasm to the nucleus, where increased interaction with Aurora kinase B could be observed. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Molecular chaperones and their associated cofactors form a group of highly specialized proteins that orchestrate the folding and unfolding of other proteins and the assembly and disassembly of protein complexes. Chaperones are found in all cell types and organisms, and their activity must be tightly regulated to maintain normal cell function. Indeed, deregulation of protein folding and protein complex assembly is the cause of various human diseases. Here, we present the results of an extensive review of the literature revealing that the post-translational modification (PTM) of chaperones has been selected during evolution as an efficient mean to regulate the activity and specificity of these key proteins. Because the addition and reciprocal removal of chemical groups can be triggered very rapidly, this mechanism provides an efficient switch to precisely regulate the activity of chaperones on specific substrates. The large number of PTMs detected in chaperones suggests that a combinatory code is at play to regulate function, activity, localization, and substrate specificity for this group of biologically important proteins. This review surveys the core information currently available as a starting point towards the more ambitious endeavor of deciphering the "chaperone code".
    Full-text · Article · Feb 2013 · Biochimica et Biophysica Acta
Show more