Association of SWAP-70 with the B cell antigen receptor complex.
SWAP-70 is a component of an enzyme complex that recombines Ig switch regions in vitro. We report here the cloning of the human cDNA and its B lymphocyte-specific expression. Although its sequence contains three nuclear localization signals, in small resting B cells, SWAP-70 is mainly found in the cytoplasm. On stimulation, SWAP-70 translocates to the nucleus. In activated, class-switching B cell cultures, it is associated with membrane IgG, but not IgM. The membrane Ig association requires a functional pleckstrin homology domain and is controlled by the C terminus. We suggest that SWAP-70 is involved not only in nuclear events but also in signaling in B cell activation.
Masat
L
L
Department of Microbiology, University of California, San Francisco, CA 94143, USA.
Caldwell
J
J
Armstrong
R
R
Khoshnevisan
H
H
Jessberger
R
R
Herndier
B
B
Wabl
M
M
Ferrick
D
D
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D019013:CD40 Antigens / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D015778:Minor Histocompatibility Antigens; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011817:Rabbits; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D019013:CD40 Antigens; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins; D011947:Receptors, Antigen, B-Cell; C491873:SWAP70 protein, human