Human p8 is a HMG-I/Y-like protein with DNA binding activity enhanced by phosphorylation

J Biol Chem. 2001 Jan 26;276(4):2742-51. doi: 10.1074/jbc.M008594200. Epub 2000 Oct 30.


We have studied the biochemical features, the conformational preferences in solution, and the DNA binding properties of human p8 (hp8), a nucleoprotein whose expression is affected during acute pancreatitis. Biochemical studies show that hp8 has properties of the high mobility group proteins, HMG-I/Y. Structural studies have been carried out by using circular dichroism (near- and far-ultraviolet), Fourier transform infrared, and NMR spectroscopies. All the biophysical probes indicate that hp8 is monomeric (up to 1 mm concentration) and partially unfolded in solution. The protein seems to bind DNA weakly, as shown by electrophoretic gel shift studies. On the other hand, hp8 is a substrate for protein kinase A (PKA). The phosphorylated hp8 (PKAhp8) has a higher content of secondary structure than the nonphosphorylated protein, as concluded by Fourier transform infrared studies. PKAhp8 binds DNA strongly, as shown by the changes in circular dichroism spectra, and gel shift analysis. Thus, although there is not a high sequence homology with HMG-I/Y proteins, hp8 can be considered as a HMG-I/Y-like protein.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Basic Helix-Loop-Helix Transcription Factors
  • Circular Dichroism
  • Conserved Sequence
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Growth Substances / genetics
  • Growth Substances / metabolism*
  • HMGA1a Protein
  • High Mobility Group Proteins*
  • Humans
  • Molecular Sequence Data
  • Neoplasm Proteins*
  • Nuclear Magnetic Resonance, Biomolecular
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Spectroscopy, Fourier Transform Infrared
  • Transcription Factors*


  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Growth Substances
  • High Mobility Group Proteins
  • NUPR1 protein, human
  • Neoplasm Proteins
  • Transcription Factors
  • HMGA1a Protein
  • Cyclic AMP-Dependent Protein Kinases