Association of SLP-65/BLNK with the B cell antigen receptor through a non-ITAM tyrosine of Ig-alpha

Eur J Immunol. 2001 Jul;31(7):2126-34. doi: 10.1002/1521-4141(200107)31:7<2126::aid-immu2126>;2-o.


The cytoplasmic adaptor protein SLP-65 (BLNK or BASH) is a critical downstream effector of the B cell antigen receptor (BCR). Tyrosine-phosphorylated SLP-65 assembles intracellular signaling complexes such as the Ca(2 +) initiation complex encompassing phospholipase C-gamma2 and Bruton's tyrosine kinase. It is, however, unclear how the SLP-65 signaling module can be recruited to the plasma membrane. Here we show that following B cell stimulation, SLP-65 associates directly with the BCR signaling subunit, the Ig-alpha / Ig-beta heterodimer. The interaction is mediated by the Src homology 2 domain of SLP-65 and the phosphorylated Ig-alpha tyrosine 204, which is located outside of the immunoreceptor tyrosine-based activation motif. Our data identify an unexpected BCR phosphorylation pattern and indicate that Ig-alpha has the capability to serve as transmembrane adaptor in BCR signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Antigens, CD / chemistry*
  • Antigens, CD / metabolism*
  • B-Lymphocytes / immunology*
  • CD79 Antigens
  • Carrier Proteins / chemistry
  • Carrier Proteins / metabolism*
  • Cell Line
  • Models, Immunological
  • Molecular Sequence Data
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Phosphotyrosine / metabolism
  • Receptors, Antigen, B-Cell / chemistry*
  • Receptors, Antigen, B-Cell / metabolism*
  • Sequence Alignment
  • src Homology Domains


  • Adaptor Proteins, Signal Transducing
  • Antigens, CD
  • B cell linker protein
  • CD79 Antigens
  • Carrier Proteins
  • Phosphoproteins
  • Receptors, Antigen, B-Cell
  • Phosphotyrosine