The primary structure of the α4 subunit of VLA-4: Homology to other integrins and a possible cell-cell adhesion function

Y. Takada, M. J. Elices, C. Crouse, M. E. Hemler

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183 Citations (Scopus)

Abstract

VLA-4 is a cell surface heterodimer in the integrin superfamily of adhesion receptors. Anti-VLA-4 antibodies inhibited cytolytic T cell activity, with inhibitory activity directed against the effector T cells rather than their targets. Thus, whereas other VLA receptors appear to mediate cell-matrix interactions, VLA-4 may have a cell-cell adhesion function. To facilitate comparative studies of VLA-4 and other integrins, cDNA clones for the human α4 subunit of VLA-4 were selected and then sequenced. The 3805 bp sequence encoded for 999 amino acids, with an N-terminus identical to that previously obtained from direct sequencing of purified α4 protein. The α4 amino acid sequence was 17-24% similar to other integrin α chains with known sequences. Part of the α4 sequence most conserved in other α chains include (i) the positions of 19/24 cysteine residues, (ii) three potential divalent cation binding sites of the general structure DXDXDGXXD and (iii) the transmembrane region. However, α4 stands apart from all other known integrin α subunit sequences because (i) α4 has neither an inserted I-domain, nor a disulfide-linked C-terminal fragment, (ii) its sequence is the most unique and (iii) only α4 has a potential protease cleavage site, near the middle of the coding region, which appears responsible for the characteristic 80000 and 70000 M(r) fragments of α4.

Original languageEnglish
Pages (from-to)1361-1368
Number of pages8
JournalEMBO Journal
Volume8
Issue number5
DOIs
Publication statusPublished - 1989

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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