The lck tyrosine protein kinase interacts with the cytoplasmic tail of the CD4 glycoprotein through its unique amino-terminal domain

Cell. 1989 Nov 17;59(4):627-36. doi: 10.1016/0092-8674(89)90008-1.


The CD4 lymphocyte surface glycoprotein and the lck tyrosine protein kinase p56lck are found as a complex in T lymphocytes. We have defined the domains in both proteins that are responsible for this interaction by coexpressing hybrid and deleted forms of the two proteins in HeLa cells. We have found that the unique 32 amino-terminal residues of p56lck and the 38 carboxy-terminal residues of CD4 that comprise the cytoplasmic domain are both necessary and sufficient by themselves for the interaction of the two proteins. The interaction appears to be independent of other T cell-specific proteins and probably occurs before CD4 reaches the cell surface. Our findings suggest that the specialized amino-terminal domains of other members of the src family of intracellular tyrosine kinases may also mediate transmembrane signaling via coupling to the cytoplasmic domains of specific transmembrane proteins.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • CD4 Antigens*
  • Cytoplasm / metabolism
  • HeLa Cells / enzymology
  • HeLa Cells / immunology
  • Humans
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
  • Macromolecular Substances
  • Membrane Glycoproteins / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Oligonucleotide Probes
  • Phosphoproteins / isolation & purification
  • Plasmids
  • Protein Binding
  • Protein Multimerization
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism*
  • T-Lymphocytes / enzymology
  • T-Lymphocytes / immunology
  • Transfection


  • CD4 Antigens
  • Macromolecular Substances
  • Membrane Glycoproteins
  • Oligonucleotide Probes
  • Phosphoproteins
  • Protein-Tyrosine Kinases
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)