CD22 associates with the human surface IgM-B-cell antigen receptor complex

Proc Natl Acad Sci U S A. 1993 Apr 15;90(8):3236-40. doi: 10.1073/pnas.90.8.3236.

Abstract

The B-cell surface molecule CD22, when cross-linked, modulates signaling through the surface IgM (sIgM)-B-cell receptor (BCR) complex. Here we analyzed the basis of this interaction between CD22 and the human sIgM complex. After lysis of B cells or B-cell lines in digitonin, CD22 coimmunoprecipitated a kinase activity that in vitro-phosphorylated two polypeptides of 150 and 130 kDa on tyrosine residues. By immunoblot analysis with a rabbit anti-serum specific for a synthetic peptide of CD22, we found these proteins to be CD22 itself. Furthermore, the phosphorylated 150-kDa CD22 was found in the sIgM-BCR complex maintained by digitonin, along with Ig alpha/mb-1, Ig beta/B29, and a 75-kDa polypeptide precipitated by an antiserum specific to protein-tyrosine kinase PTK72. CD22 is likely to be an important signaling partner in the sIgM-BCR complex since it is very rapidly and strikingly phosphorylated after sIgM is cross-linked and since it contains the antigen recognition homology I (ARHI) motif, present in other antigen receptor molecules.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / isolation & purification
  • Antigens, CD / metabolism*
  • Antigens, Differentiation, B-Lymphocyte / genetics
  • Antigens, Differentiation, B-Lymphocyte / isolation & purification
  • Antigens, Differentiation, B-Lymphocyte / metabolism*
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / metabolism
  • Burkitt Lymphoma
  • Cell Adhesion Molecules / isolation & purification
  • Cell Adhesion Molecules / metabolism*
  • Cell Membrane / immunology
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Immunoglobulin M / isolation & purification
  • Immunoglobulin M / metabolism*
  • Lectins*
  • Mice
  • Molecular Sequence Data
  • Molecular Weight
  • Palatine Tonsil / immunology
  • Protein Kinases / isolation & purification
  • Protein Kinases / metabolism*
  • Receptors, Antigen, B-Cell / isolation & purification
  • Receptors, Antigen, B-Cell / metabolism*
  • Sequence Homology, Amino Acid
  • Sialic Acid Binding Ig-like Lectin 2
  • Tumor Cells, Cultured

Substances

  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • CD22 protein, human
  • Cd22 protein, mouse
  • Cell Adhesion Molecules
  • Immunoglobulin M
  • Lectins
  • Receptors, Antigen, B-Cell
  • Sialic Acid Binding Ig-like Lectin 2
  • Protein Kinases