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Properties of the co‐chaperone protein p23 erroneously attributed to ALG‐2 (apoptosis‐linked gene 2)
Author(s) -
Mollerup Jens,
Krogh Thomas N,
Nielsen Per F,
Berchtold Martin W
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01310-3
Subject(s) - immunoprecipitation , heat shock protein , microbiology and biotechnology , chaperone (clinical) , hsp90 , antigen , clone (java method) , antibody , cytosol , gene , hsp70 , biology , chemistry , hspa4 , biochemistry , enzyme , medicine , genetics , pathology
A commercial antibody (clone 22) directed against the apoptosis‐linked gene 2 (alg2, pdcd6) encoded protein has been used by several groups. Up‐regulated expression of the antigen was observed in primary tumours and in metastatic tissue and also during rat brain ischemia. Furthermore, antigen down‐regulation was found in human atherosclerotic plaques. Recently, we found that the clone 22 antibody does not recognise ALG‐2. In the present study the antigen of the clone 22 antibody was identified as the heat shock protein 90 (HSP90) co‐chaperone protein p23, identical to the cytosolic prostaglandin E2 synthase, by immunoprecipitation followed by tryptic in‐gel digests and mass spectrometry of the purified peptides. Moreover, the heterogeneous ribonuclear protein A2/B1 was found to be a part of the p23 co‐immunoprecipitated protein complex.