Functional domains of the 67-kDa laminin receptor precursor

Vincent Castronovo, Giulia Taraboletti, Mark E. Sobel

Research output: Contribution to journalArticlepeer-review

Abstract

We report the characterization of two functional domains of the metastasis-associated 67-kDa laminin receptor (67-LR). Using synthetic peptides deduced from the cDNA sequence of the 37-kDa precursor of the laminin receptor (37-LRP) as well as their corresponding affinity-purified polyclonal antibodies, we identified a unique laminin binding site as well as a membrane-associated domain of the receptor. In laminin dot blot and solid phase radioligand assays, a 20 amino acid synthetic peptide (IPCNNKGAHSV-GLMWWMLAR, amino acid residues 161-180, designated peptide G) specifically bound to laminin with high affinity (Kd = 5 × 10-8 M). Peptide G also specifically eluted the 67-LR from a laminin affinity column. Peptide G and laminin reacted with a 1:1 stoichiometry, suggesting that there is one recognition site on laminin for the peptide G domain. Immunofluorescence studies, performed on permeabilized and nonpermeabilized human A2058 melanoma cells using 10 different affinity-purified antibodies to distinct regions of the 37-LRP, identified an unusually short membrane-associated domain that was consistent with a computer predicted transmembrane domain (residues 86-101). Our data demonstrate for the first time that the 37-LRP has two functional domains consistent with the characteristics of the mature 67-LR. Furthermore, we propose peptide G as a potential inhibitor of tumor cell interactions with laminin.

Original languageEnglish
Pages (from-to)20440-20446
Number of pages7
JournalJournal of Biological Chemistry
Volume266
Issue number30
Publication statusPublished - 1991

ASJC Scopus subject areas

  • Biochemistry

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