Molecular cloning and preliminary characterization of a novel cytoplasmic antigen recognized by myasthenia gravis sera

Tom Gordon, Bryon Grove, Joseph C. Loftus, Tim O'Toole, Robert McMillan, Jon Lindstrom, Mark H. Ginsberg

Research output: Contribution to journalArticle

80 Scopus citations

Abstract

A cDNA clone was isolated by screening of a λgt11 endothelial expression library with serum from a patient with myasthenia gravis (MG). Rabbit antisera raised against the recombinant protein and human MG sera reactive with the clone immunoblotted an Mr ∼ 250,000 polypeptide (gravin) present in endothelial cells and several adherent cells. Gravin was not detected in platelets, leukocytes, U937, or human erythroleukemic (HEL) cell lines, but was expressed in HEL cells after induction with phorbol myristate acetate. Northern blot analysis showed two transcripts of ∼ 6.7 and 8.4 kb in endothelial cells but not U937 or HEL cells. Indirect immunofluorescence of permeabilized cells revealed a trabecular network of gravin staining with a distinct linear component. Antibodies to gravin were present in sera from 22:72 (31%) of MG patients. In contrast 0:50 normal sera and 1:72 sera from patients with other autoimmune diseases contained antigravin antibodies. Gravin is not likely to be a nonerythroid spectrin, talin, myosin, or actin-binding protein based on the lack of reactivity of antigravin with these polypeptides in immunoblots. The nucleotide sequence of the immunoreactive clone indicated that it encodes a highly acidic polypeptide fragment that contains the carboxyl terminus of the protein. Neither amino acid nor nucleotide sequences were present in Genbank, EMBL, or Swissprot databases as of March, 1992. These data indicate that gravin is an inducible, cell type-specific cytoplasmic protein and that autoantibodies to gravin may be highly specific for MG.

Original languageEnglish (US)
Pages (from-to)992-999
Number of pages8
JournalJournal of Clinical Investigation
Volume90
Issue number3
DOIs
Publication statusPublished - Jan 1 1992

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Keywords

  • Autoimmunity
  • Cell adhesion
  • Gravin
  • Molecular cloning
  • Myasthenia gravis

ASJC Scopus subject areas

  • Medicine(all)

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