Distinct OGT-Binding Sites Promote HCF-1 Cleavage

PLoS One. 2015 Aug 25;10(8):e0136636. doi: 10.1371/journal.pone.0136636. eCollection 2015.


Human HCF-1 (also referred to as HCFC-1) is a transcriptional co-regulator that undergoes a complex maturation process involving extensive O-GlcNAcylation and site-specific proteolysis. HCF-1 proteolysis results in two active, noncovalently associated HCF-1N and HCF-1C subunits that regulate distinct phases of the cell-division cycle. HCF-1 O-GlcNAcylation and site-specific proteolysis are both catalyzed by O-GlcNAc transferase (OGT), which thus displays an unusual dual enzymatic activity. OGT cleaves HCF-1 at six highly conserved 26 amino acid repeat sequences called HCF-1PRO repeats. Here we characterize the substrate requirements for OGT cleavage of HCF-1. We show that the HCF-1PRO-repeat cleavage signal possesses particular OGT-binding properties. The glutamate residue at the cleavage site that is intimately involved in the cleavage reaction specifically inhibits association with OGT and its bound cofactor UDP-GlcNAc. Further, we identify a novel OGT-binding sequence nearby the first HCF-1PRO-repeat cleavage signal that enhances cleavage. These results demonstrate that distinct OGT-binding sites in HCF-1 promote proteolysis, and provide novel insights into the mechanism of this unusual protease activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cytokinesis / genetics
  • Glutamic Acid / metabolism
  • HeLa Cells
  • Host Cell Factor C1 / genetics
  • Host Cell Factor C1 / metabolism*
  • Humans
  • N-Acetylglucosaminyltransferases / genetics
  • N-Acetylglucosaminyltransferases / metabolism*
  • Protein Subunits / genetics
  • Protein Subunits / metabolism*
  • Proteolysis*
  • Repetitive Sequences, Amino Acid / genetics
  • Transcription, Genetic*


  • HCFC1 protein, human
  • Host Cell Factor C1
  • Protein Subunits
  • Glutamic Acid
  • N-Acetylglucosaminyltransferases
  • O-GlcNAc transferase

Grants and funding

This work was supported by the Swiss National Science Foundation (SNSF) grant 31003A_130829 (URL: http://www.snf.ch/en/Pages/default.aspx) and the University of Lausanne to WH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.