BASH, a novel signaling molecule preferentially expressed in B cells of the bursa of Fabricius.
The bursa of Fabricius is a gut-associated lymphoid organ that is essential for the generation of a diversified B cell repertoire in the chicken. We describe here a novel gene preferentially expressed in bursal B cells. The gene encodes an 85-kDa protein, designated BASH (B cell adaptor containing SH2 domain), that contains N-terminal acidic domains with SH2 domain-binding phosphotyrosine-based motifs, a proline-rich domain, and a C-terminal SH2 domain. BASH shows a substantial sequence similarity to SLP-76, an adaptor protein functioning in TCR-signal transduction. BASH becomes tyrosine-phosphorylated with the B cell Ag receptor (BCR) cross-link or by coexpression with Syk and Lyn and associates with signaling molecules including Syk and a putative chicken Shc homologue. Overexpression of BASH results in suppression of the NF-AT activation induced by BCR-cross-linking. These findings suggest that BASH is involved in BCR-mediated signal transduction and could play a critical role in B cell development in the bursa.
Goitsuka
R
R
Inheritance and Variation Group, PREST, JST, Kyoto, Japan. ryogoi@rs.noda.sut.ac.jp
Fujimura
Y
Y
Mamada
H
H
Umeda
A
A
Morimura
T
T
Uetsuka
K
K
Doi
K
K
Tsuji
S
S
Kitamura
D
D
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002060:Bursa of Fabricius / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D002352:Carrier Proteins; D002460:Cell Line; D002645:Chickens; D018076:DNA, Complementary / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism / Q000502:physiology; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction / Q000276:immunology*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D000072377:Syk Kinase; D014157:Transcription Factors / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains / Q000276:immunology*; D019061:src-Family Kinases / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C113939:B cell linker protein; D002352:Carrier Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D004792:Enzyme Precursors; D007075:Immunoglobulin M; D047908:Intracellular Signaling Peptides and Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014157:Transcription Factors; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D019061:src-Family Kinases