Abstract
BCMA (B cell maturation) is a nonglycosylated integral membrane type I protein that is preferentially expressed in mature B lymphocytes. Previously, we reported in a human malignant myeloma cell line that BCMA is not primarily present on the cell surface but lies in a perinuclear structure that partially overlaps the Golgi apparatus. We now show that in transiently or stably transfected cells, BCMA is located on the cell surface, as well as in a perinulear Golgi-like structure. We also show that overexpression of BCMA in 293 cells activates NF-kappa B, Elk-1, the c-Jun N-terminal kinase, and the p38 mitogen-activated protein kinase. Coimmunoprecipitation experiments performed in transfected cells showed that BCMA associates with TNFR-associated factor (TRAF) 1, TRAF2, and TRAF3 adaptor proteins. Analysis of deletion mutants of the intracytoplasmic tail of BCMA showed that the 25-aa protein segment, from position 119 to 143, conserved between mouse and human BCMA, is essential for its association with the TRAFs and the activation of NF-kappa B, Elk-1, and c-Jun N-terminal kinase. BCMA belongs structurally to the TNFR family. Its unique TNFR motif corresponds to a variant motif present in the fourth repeat of the TNFRI molecule. This study confirms that BCMA is a functional member of the TNFR superfamily. Furthermore, as BCMA is lacking a "death domain" and its overexpression activates NF-kappa B and c-Jun N-terminal kinase, we can reasonably hypothesize that upon binding of its corresponding ligand BCMA transduces signals for cell survival and proliferation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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B-Cell Maturation Antigen
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B-Lymphocytes / cytology
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B-Lymphocytes / metabolism*
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Cell Differentiation / immunology
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Cell Line
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Cell Membrane / immunology
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Cell Membrane / metabolism
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Cell Nucleus / immunology
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Cell Nucleus / metabolism
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Cytoplasm / immunology
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Cytoplasm / metabolism
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DNA-Binding Proteins*
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Enzyme Activation / immunology
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Genetic Vectors / pharmacology
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Humans
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Intracellular Fluid / immunology
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Intracellular Fluid / metabolism
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JNK Mitogen-Activated Protein Kinases
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MAP Kinase Signaling System / immunology
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Mice
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Mitogen-Activated Protein Kinases / metabolism*
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Molecular Sequence Data
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NF-kappa B / antagonists & inhibitors
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NF-kappa B / metabolism*
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Peptide Mapping
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Proteins / genetics
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Proteins / metabolism
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Proteins / physiology
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Proto-Oncogene Proteins / metabolism*
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Receptors, Tumor Necrosis Factor / antagonists & inhibitors
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Receptors, Tumor Necrosis Factor / genetics
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Receptors, Tumor Necrosis Factor / metabolism*
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Receptors, Tumor Necrosis Factor / physiology
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Sequence Deletion
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TNF Receptor-Associated Factor 1
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TNF Receptor-Associated Factor 2
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TNF Receptor-Associated Factor 3
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Transcription Factors*
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Tumor Cells, Cultured
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ets-Domain Protein Elk-1
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p38 Mitogen-Activated Protein Kinases
Substances
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B-Cell Maturation Antigen
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DNA-Binding Proteins
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ELK1 protein, human
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Elk1 protein, mouse
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NF-kappa B
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Proteins
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Proto-Oncogene Proteins
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Receptors, Tumor Necrosis Factor
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TNF Receptor-Associated Factor 1
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TNF Receptor-Associated Factor 2
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TNF Receptor-Associated Factor 3
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TNFRSF17 protein, human
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Tnfrsf17 protein, mouse
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Transcription Factors
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ets-Domain Protein Elk-1
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JNK Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinases
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p38 Mitogen-Activated Protein Kinases