The methyltransferase WBSCR22/Merm1 enhances glucocorticoid receptor function and is regulated in lung inflammation and cancer

J Biol Chem. 2014 Mar 28;289(13):8931-46. doi: 10.1074/jbc.M113.540906. Epub 2014 Jan 31.

Abstract

Glucocorticoids (GC) regulate cell fate and immune function. We identified the metastasis-promoting methyltransferase, metastasis-related methyltransferase 1 (WBSCR22/Merm1) as a novel glucocorticoid receptor (GR) regulator relevant to human disease. Merm1 binds the GR co-activator GRIP1 but not GR. Loss of Merm1 impaired both GR transactivation and transrepression by reducing GR recruitment to its binding sites. This was accompanied by loss of GR-dependent H3K4Me3 at a well characterized promoter. Inflammation promotes GC resistance, in part through the actions of TNFα and IFNγ. These cytokines suppressed Merm1 protein expression by driving ubiquitination of two conserved lysine residues. Restoration of Merm1 expression rescued GR transactivation. Cytokine suppression of Merm1 and of GR function was also seen in human lung explants. In addition, striking loss of Merm1 protein was observed in both inflammatory and neoplastic human lung pathologies. In conclusion, Merm1 is a novel regulator of chromatin structure affecting GR recruitment and function, contributing to loss of GC sensitivity in inflammation, with suppressed expression in pulmonary disease.

Keywords: Glucocorticoid Receptor; Glucocorticoids; Histone Methylation; Inflammation; Interferon; Lung; Tumor Necrosis Factor (TNF); Ubiquitination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • B-Lymphocytes / drug effects
  • B-Lymphocytes / metabolism
  • Bronchi / pathology
  • CD8-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / metabolism
  • Cell Line, Tumor
  • Chromatin Assembly and Disassembly / drug effects
  • Epithelium / drug effects
  • Epithelium / metabolism
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glucocorticoids / metabolism
  • Histones / chemistry
  • Histones / metabolism
  • Humans
  • Inflammation / genetics
  • Inflammation / metabolism
  • Inflammation / pathology
  • Interferon-gamma / pharmacology
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology
  • Lysine / metabolism
  • Methylation / drug effects
  • Methyltransferases / chemistry
  • Methyltransferases / metabolism*
  • Protein Binding
  • Protein Kinases / metabolism
  • Protein Structure, Tertiary
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, Glucocorticoid / genetics
  • Receptors, Glucocorticoid / metabolism*
  • Signal Transduction / drug effects
  • Transcriptional Activation / drug effects
  • Tumor Necrosis Factor-alpha / pharmacology
  • Ubiquitination / drug effects

Substances

  • Glucocorticoids
  • Histones
  • RNA, Messenger
  • Receptors, Glucocorticoid
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma
  • BUD23 protein, human
  • Methyltransferases
  • Protein Kinases
  • Lysine