Src and Syk kinases: key regulators of phagocytic cell activation

Trends Immunol. 2005 Apr;26(4):208-14. doi: 10.1016/


Src-family kinases and Syk tyrosine kinases have crucial roles in multiple leukocyte intracellular signaling pathways. In immunoreceptor-related pathways, these enzymes work together sequentially, with Src-family kinases phosphorylating specific protein substrates, which in turn recruit and activate Syk. Recent evidence indicates that several non-immunoreceptors also use Src-family kinases and Syk in this same fashion. In leukocyte integrin signaling, the interaction between the kinases is more complex, where they appear to act in a sequential manner but the mechanisms by which they are activated remain poorly defined. Elucidating the regulation of these tyrosine kinase-based signaling pathways in leukocytes remains an important goal in understanding how immune cells respond to the multitude of activating agents they encounter.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Enzyme Precursors / metabolism*
  • Inflammation / enzymology
  • Inflammation / immunology
  • Integrins / metabolism
  • Intracellular Signaling Peptides and Proteins
  • Mice
  • Mice, Knockout
  • Models, Immunological
  • Phagocytes / enzymology*
  • Phagocytes / immunology*
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Immunologic / metabolism
  • Signal Transduction
  • Syk Kinase
  • src-Family Kinases / metabolism*


  • Enzyme Precursors
  • Integrins
  • Intracellular Signaling Peptides and Proteins
  • Receptors, Immunologic
  • Protein-Tyrosine Kinases
  • Syk Kinase
  • Syk protein, mouse
  • src-Family Kinases