Insulin-like growth factor (IGF) binding protein complementary deoxyribonucleic acid from human HEP G2 hepatoma cells: predicted protein sequence suggests an IGF binding domain different from those of the IGF-I and IGF-II receptors

Mol Endocrinol. 1988 May;2(5):404-11. doi: 10.1210/mend-2-5-404.

Abstract

The primary structure of an insulin-like growth factor (IGF) binding protein produced by human HEP G2 hepatoma cells has been deduced from the cDNA sequence. The 234 amino acid protein has a predicted molecular mass of 25,274 and contains a single, distinctive cysteine-rich region. The N-terminal sequence of this protein is quite similar to the limited sequence data available for a rat IGF binding protein produced by BRL-3A cells and suggests a common ancestral origin. In contrast, the HEP G2 IGF binding protein sequence bears no similarity to the N-terminal 15 amino acids of a 53 kilodalton binding protein purified from human plasma. Comparison of full-length protein sequences for the IGF-I and IGF-II receptors with that of the HEP G2 IGF binding protein also fails to demonstrate any significant similarities among these three proteins, and suggests that each contains a unique binding domain for the IGF peptides.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Binding Sites
  • Carrier Proteins* / genetics
  • Carrier Proteins* / isolation & purification
  • Chromosome Mapping
  • Cloning, Molecular
  • DNA Restriction Enzymes
  • DNA, Neoplasm / genetics
  • Humans
  • Insulin-Like Growth Factor Binding Proteins
  • Molecular Sequence Data
  • Receptor, Insulin*
  • Receptors, Somatomedin
  • Somatomedins* / genetics
  • Somatomedins* / isolation & purification
  • Tumor Cells, Cultured

Substances

  • Carrier Proteins
  • DNA, Neoplasm
  • Insulin-Like Growth Factor Binding Proteins
  • Receptors, Somatomedin
  • Somatomedins
  • Receptor, Insulin
  • DNA Restriction Enzymes