Anti-Sm autoantibodies cross-react with ribosomal protein S10 - A common structural unit shared by the small nuclear RNP proteins and the ribosomal protein

作者：Hasegawa H; Uchiumi T^*; Sato T; Arakawa M; Kominami R

来源：Arthritis and Rheumatism, 1998, 41(6): 1040-1046.

DOI：10.1002/1529-0131(199806)41:6<1040::AID-ART10>3.0.CO;2-2

Objective. Cross-reactivity of anti-Sm autoantibodies,vith a certain ribosomal protein has been reported previously, The present study was undertaken to identify the anti-Sm-reactive ribosomal protein, and to characterize the cross-reactive epitope,
Methods. Two-dimensional gel electrophoresis followed by immunoblotting was used to identify the ribosomal protein (S10) which was reactive with the Y12 anti-Sm monoclonal antibody (MAb). Human anti-Sm antibodies were also tested for cross-reactivity with the Sm-B/B', Sm-D, and isolated S10 proteins by immunoblotting. Epitope analysis was performed by immunoprecipitation of in vitro-translated products of the recombinant S10 and its various mutants,
Results. The Y12 MAb and the affinity-purified human anti-Sm autoantibodies cross-reacted with ribosomal S10 protein. Reactivity of the Y12 MAb with S10 protein was abolished by deletion of 19 amino acids at the carboxyl-terminus of S10, containing the Gly-Arg-Gly sequence motif shared by Sm-B/B' and Sm-D (D1 and D3). Replacements of Arg-158 with Gly and of Arg-158/Arg-160 with Gly/Gly at the carboxyl-terminal 157-Gly-Arg-Gly-Arg-Gly region disrupted the Y12 MAb recognition.
Conclusion. At least a part of human anti-Sm antibodies and Y12 MAb show cross-reactivity among Sm-B/B', Sm-D, and ribosomal protein S10, The carboxyl-terminal Gly-Arg-Gly region of S10 protein is involved in constructing the cross-reactive epitope. This demonstrates that a common structural feature is shared by the ribosomal protein and the small nuclear RNP proteins.

• 出版日期1998-6