Comparison of multiple forms of the high mobility group I proteins in rodent and human cells. Identification of the human high mobility group I-C protein

Eur J Biochem. 1991 May 23;198(1):211-6. doi: 10.1111/j.1432-1033.1991.tb16003.x.


The class I of the high mobility group (HMG) proteins is formed by phosphoproteins which are associated with AT-rich DNA sequences in the nucleus. Three HMGI proteins have previously been described in proliferating rodent cells (HMG Y, HMG I and HMGI-C). All three proteins exhibit microheterogeneity. The microheterogeneity of mouse HMG Y has been investigated in detail and shown to be due to phosphorylation of the protein which is sensitive to alkaline-phosphatase treatment. HMG I is similarly modified. Human cells have up to now only been found to contain HMG Y and HMG I. A search for the third protein, HMGI-C, in human cells was carried out and the protein was found in a hepatoma cell line, but not in normal or transformed T-cells. This HMGI-C protein was found to be modified by phosphorylation, part of which was found to be phosphatase insensitive. An unexpected additional finding in this study was that human cells contain two HMG17 proteins which differ in their N-terminal primary sequences.

Publication types

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

MeSH terms

  • Alkaline Phosphatase / chemistry
  • Amino Acid Sequence
  • Animals
  • Chromatography, High Pressure Liquid
  • Electrophoresis, Gel, Two-Dimensional
  • Electrophoresis, Polyacrylamide Gel
  • High Mobility Group Proteins / chemistry*
  • Humans
  • Molecular Sequence Data
  • Rodentia
  • Tumor Cells, Cultured


  • High Mobility Group Proteins
  • Alkaline Phosphatase