Activation of BTK by a phosphorylation mechanism initiated by SRC family kinases

Science. 1996 Feb 9;271(5250):822-5. doi: 10.1126/science.271.5250.822.


Bruton's tyrosine kinase (BTK) is pivotal in B cell activation and development through its participation in the signaling pathways of multiple hematopoietic receptors. The mechanisms controlling BTK activation were studied here by examination of the biochemical consequences of an interaction between BTK and SRC family kinases. This interaction of BTK with SRC kinases transphosphorylated BTK on tyrosine at residue 551, which led to BTK activation. BTK then autophosphorylated at a second site. The same two sites were phosphorylated upon B cell antigen receptor cross-linking. The activated BTK was predominantly membrane-associated, which suggests that BTK integrates distinct receptor signals resulting in SRC kinase activation and BTK membrane targeting.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Agammaglobulinaemia Tyrosine Kinase
  • Animals
  • B-Lymphocytes / enzymology*
  • Cell Line, Transformed
  • Cell Membrane / enzymology
  • Enzyme Activation
  • Immunoglobulin M / immunology
  • Lymphocyte Activation
  • Mice
  • Mutation
  • Phosphopeptides / analysis
  • Phosphorylation
  • Phosphotyrosine / metabolism
  • Protein-Tyrosine Kinases / chemistry
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Antigen, B-Cell / metabolism
  • Signal Transduction
  • src-Family Kinases / metabolism*


  • Immunoglobulin M
  • Phosphopeptides
  • Receptors, Antigen, B-Cell
  • Phosphotyrosine
  • Protein-Tyrosine Kinases
  • Agammaglobulinaemia Tyrosine Kinase
  • Btk protein, mouse
  • src-Family Kinases