TY - JOUR
T1 - Synthetic glycan ligand excludes CD22 from antigen receptor-containing lipid rafts
AU - Yu, Jie
AU - Sawada, Toshihiko
AU - Adachi, Takahiro
AU - Gao, Xiaoming
AU - Takematsu, Hiromu
AU - Kozutsumi, Yasunori
AU - Ishida, Hideharu
AU - Kiso, Makoto
AU - Tsubata, Takeshi
N1 - Funding Information:
We thank Dr. M. Wabl (University of California, San Francisco, CA) for QM mice, Dr. T. Kitamura (The University of Tokyo, Japan) for retrovirus vector and packaging cell, and A. Yoshino for technical help. This work was supported in part by grants from the Ministry of Education, Culture, Sports, Science and Technology, and Japan Society for the Promotion of Science.
PY - 2007/9/7
Y1 - 2007/9/7
N2 - CD22/Siglec-2 is a B cell membrane-bound lectin that recognizes glycan ligands containing α2,6-linked sialic acid, and negatively regulates signaling through the B cell antigen receptor (BCR). Previous studies demonstrated that synthetic sialosides that bind to CD22 augment BCR signaling by inhibiting CD22-mediated BCR regulation. Here we demonstrate that, after antigen stimulation, CD22 forms a cap together with BCR, and translocates to lipid rafts. Both co-capping of CD22 with BCR and translocation of CD22 to lipid rafts were markedly blocked by a synthetic α2,6-linked sialic acid, Neu5Gcα2-6GalβSE. These results strongly suggest that synthetic glycan ligand excludes CD22 from BCR-containing lipid rafts. Because CD22-mediated signal regulation requires phosphorylation of CD22 by Lyn that localizes in lipid rafts and is activated by BCR, synthetic glycan ligand regulates localization of CD22 crucial for signal regulation.
AB - CD22/Siglec-2 is a B cell membrane-bound lectin that recognizes glycan ligands containing α2,6-linked sialic acid, and negatively regulates signaling through the B cell antigen receptor (BCR). Previous studies demonstrated that synthetic sialosides that bind to CD22 augment BCR signaling by inhibiting CD22-mediated BCR regulation. Here we demonstrate that, after antigen stimulation, CD22 forms a cap together with BCR, and translocates to lipid rafts. Both co-capping of CD22 with BCR and translocation of CD22 to lipid rafts were markedly blocked by a synthetic α2,6-linked sialic acid, Neu5Gcα2-6GalβSE. These results strongly suggest that synthetic glycan ligand excludes CD22 from BCR-containing lipid rafts. Because CD22-mediated signal regulation requires phosphorylation of CD22 by Lyn that localizes in lipid rafts and is activated by BCR, synthetic glycan ligand regulates localization of CD22 crucial for signal regulation.
KW - B cell antigen receptor
KW - B lymphocyte
KW - CD22
KW - Lipid rafts
KW - Sialoside
KW - Siglec
KW - α2,6-Linked sialic acid
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U2 - 10.1016/j.bbrc.2007.06.110
DO - 10.1016/j.bbrc.2007.06.110
M3 - Article
C2 - 17631277
AN - SCOPUS:34447546530
SN - 0006-291X
VL - 360
SP - 759
EP - 764
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -