Characterization of human autoantibodies that selectively precipitate the 7SL RNA component of the signal recognition particle

N. Okada, T. Mimori, R. Mukai, H. Kashiwagi, J. A. Hardin

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

The signal recognition particle (SRP), which consists of the 7SL RNA molecule associated with six polypeptides ranging between 9,000 and 72,000 m.w., mediates the translocation of newly synthesized proteins across the endoplasmic reticulum. We have characterized autoantibodies that are directed against this particle from two patients with rheumatic diseases. These sera immunoprecipitated the 7SL RNA from whom whole extracts of HeLa cells radiolabeled with 32P, but no RNA from deproteinized cell extracts. From 35S-methionine-labeled cell extracts, they immunoprecipitated a single polypeptide of 54,000 m.w. that is consistent with a known SRP component. Sucrose density gradient studies confirmed that this protein co-migrated with the 7SL RNA, indicating the likelihood that it is physically associated with this RNA. Thus, the 54,000 m.w. SRP protein, which is essential for the SRP functions of elongation arrest and translocation, appears to be a preferential target for human autoimmune responses. Human autoantibodies that recognize the SRP should be useful adjuncts to animal antisera for studies of the structure and function of this particle.

Original languageEnglish (US)
Pages (from-to)3219-3223
Number of pages5
JournalJournal of Immunology
Volume138
Issue number10
StatePublished - Jul 13 1987

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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