Crosstalk between O-GlcNAcylation and proteolytic cleavage regulates the host cell factor-1 maturation pathway

Proc Natl Acad Sci U S A. 2011 Feb 15;108(7):2747-52. doi: 10.1073/pnas.1013822108. Epub 2011 Feb 1.

Abstract

Host Cell Factor 1 (HCF-1) plays critical roles in regulating gene expression in a plethora of physiological processes. HCF-1 is first synthesized as a precursor, and subsequently specifically proteolytically cleaved within a large middle region termed the proteolytic processing domain (PPD). Although the underlying mechanism remains enigmatic, proteolysis of HCF-1 regulates its transcriptional activity and is important for cell cycle progression. Here we report that HCF-1 proteolysis is a regulated process. We demonstrate that a large proportion of the signaling enzyme O-linked-N-acetylglucosaminyl transferase (OGT) is complexed with HCF-1 and this interaction is essential for HCF-1 cleavage. Moreover, HCF-1 is, in turn, required for stabilizing OGT in the nucleus. We provide evidence indicating that OGT regulates HCF-1 cleavage via interaction with and O-GlcNAcylation of the HCF-1 PPD. In contrast, although OGT also interacts with the basic domain in the HCF-1 amino-terminal subunit, neither the interaction nor the O-GlcNAcylation of this region are required for proteolysis. Moreover, we show that OGT-mediated modulation of HCF-1 impacts the expression of the herpes simplex virus immediate-early genes, targets of HCF-1 during the initiation of viral infection. Together the data indicate that O-GlcNAcylation of HCF-1 is a signal for its proteolytic processing and reveal a unique crosstalk between these posttranslational modifications. Additionally, interactions of OGT with multiple HCF-1 domains may indicate that OGT has several functions in association with HCF-1.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Blotting, Western
  • Cell Line
  • Cell Nucleus / metabolism*
  • Chromatin Immunoprecipitation
  • Fluorescent Antibody Technique
  • Gene Expression Regulation / genetics
  • Gene Expression Regulation / physiology*
  • Host Cell Factor C1 / metabolism*
  • Humans
  • Immediate-Early Proteins / metabolism
  • Immunoprecipitation
  • Mutagenesis
  • N-Acetylglucosaminyltransferases / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Simplexvirus / metabolism

Substances

  • HCFC1 protein, human
  • Host Cell Factor C1
  • Immediate-Early Proteins
  • N-Acetylglucosaminyltransferases
  • UDP-N-acetylglucosamine-peptide beta-N-acetylglucosaminyltransferase