Evidence for a precursor of the high-affinity metastasis-associated murine laminin receptor

Biochemistry. 1989 Sep 5;28(18):7476-86. doi: 10.1021/bi00444a047.

Abstract

The high-affinity cellular receptor for the basement membrane component laminin is differentially expressed during tumor invasion and metastasis. A cDNA clone encoding the murine laminin receptor was isolated and identified on the basis of sequence homology to the human laminin receptor [Wewer et al. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 7137-7141]. Primer extension experiments demonstrated that the clone contained the complete 5' sequence of the murine laminin receptor mRNA. RNA blot data demonstrated a single-sized laminin receptor mRNA, approximately 1400 bases long, in human, mouse, and rat. The nascent laminin receptor predicted from the cDNA sequence is 295 amino acids long, with a molecular weight of 33,000, and contains one intradisulfide bridge, a short putative transmembrane domain, and an extracellular carboxy-terminal region which has abundant glutamic acid residues and multiple repeat sequences. The precursor of the laminin receptor is apparently smaller than the 67-kilodalton protein isolated from tissue. The apparent molecular weight on SDS-polyacrylamide gels of the rabbit reticulocyte cell-free translation product of selectively hybridized laminin receptor mRNA is 37,000. Antisera to three different domains of the cDNA-predicted receptor were used to study the relationship between the 37- and 67-kilodalton polypeptides. Antisera to cDNA-deduced synthetic peptides of the receptor immunoprecipitated a 37-kilodalton band both from cell-free translation products and from pulse-labeled cell extracts. On immunoblots of cell extracts, one antisynthetic peptide antiserum recognized only the 67-kilodalton receptor, while another antiserum identified both 37- and 67-kilodalton polypeptides, suggesting a precursor-product relationship between the two polypeptides.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • DNA / genetics
  • Humans
  • Immunoblotting
  • Laminin / metabolism*
  • Mice
  • Molecular Sequence Data
  • Neoplasm Metastasis*
  • Nucleic Acid Conformation
  • Nucleic Acid Hybridization
  • Protein Biosynthesis
  • Protein Conformation
  • Protein Precursors / genetics*
  • Protein Precursors / metabolism
  • RNA, Messenger
  • Rats
  • Receptors, Immunologic / genetics*
  • Receptors, Immunologic / metabolism
  • Receptors, Laminin
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Tumor Cells, Cultured

Substances

  • Laminin
  • Protein Precursors
  • RNA, Messenger
  • Receptors, Immunologic
  • Receptors, Laminin
  • DNA

Associated data

  • GENBANK/J02870