An alternative way of CD4 and CD8 association with protein kinases of the Src family.
The T-lymphocyte co-receptors of MHC glycoproteins CD4 and CD8 are known to be associated with the protein tyrosine kinase Lck via cysteine-containing sequences in the cytoplasmic domains of CD4 and CD8 and in the N-terminal domain of Lck. Here we demonstrate that a fraction of CD4 and CD8 molecules are associated with very large, detergent-resistant complexes containing several glycosylphosphatidylinositol-anchored proteins, (glyco)lipids, and protein tyrosine kinases Lck and Fyn but apparently no other major transmembrane proteins. Association of Lck and Fyn with these large complexes is, in contrast to simple CD4/CD8-Lck complexes, not sensitive to alkylation with iodoacetamide. These large complexes therefore represent an alternative way of association of CD4 and CD8 with the protein tyrosine kinases, which may play a role in signaling through these receptors.
Cinek
T
T
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Praha.
Hilgert
I
I
Horejsí
V
V
D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens / Q000032:analysis*; D002462:Cell Membrane / Q000737:chemistry*; D017261:Glycosylphosphatidylinositols; D006801:Humans; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008214:Lymphocytes / Q000737:chemistry*; D009363:Neoplasm Proteins; D011505:Protein-Tyrosine Kinases / Q000032:analysis* / Q000145:classification
D015704:CD4 Antigens; D016827:CD8 Antigens; D017261:Glycosylphosphatidylinositols; D009363:Neoplasm Proteins; D011505:Protein-Tyrosine Kinases; C092830:FRK protein, human; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)