Identification and characterization of a novel OCA-B isoform. implications for a role in B cell signaling pathways.
OCA-B is a B lymphocyte-specific transcription coactivator that mediates tissue- and stage-restricted transcription of immunoglobulin genes. Earlier genetic studies revealed that OCA-B is essential for germinal center formation and production of secondary immunoglobulin isotypes. Biochemically purified OCA-B contains p35 and p34 isoforms, and a further analysis has now revealed that p35 is derived from a newly found isoform, p40. More importantly, it has been found that p35 is myristoylated in vivo and that this leads to dramatic changes (including localization to membrane compartments) in its properties. These results suggest that the p35 isoform of OCA-B has functions distinct from those of the nuclear p34 and that it might be a component of a signaling pathway that is required for late-stage B cell development.
Yu
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Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Wang
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Luo
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Roeder
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D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D001483:Base Sequence; D019556:COS Cells; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009227:Myristic Acids / Q000378:metabolism; D010442:Peptide Chain Initiation, Translational; D020033:Protein Isoforms / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D014162:Transfection
D017931:DNA Primers; D018076:DNA, Complementary; D009227:Myristic Acids; C091546:POU2AF1 protein, human; C490424:Pou2af1 protein, mouse; D020033:Protein Isoforms; D011994:Recombinant Proteins; D015534:Trans-Activators