Exp Mol Med.  2000 Mar;32(1):18-22.

Cross-linking of CD4 induces cytoskeletal association of CD4 and p56lck

• Ha-Lee YM
• Lee YS
• Kim YK
• Sohn JW

Abstract

A membrane glycoprotein CD4 functions as a co-receptor of a T lymphocyte. The co-receptor function has been attributed to a protein tyrosine kinase, p56lck, which is activated upon CD4 binding to MHC molecule. In this study, we present evidences that one of the pathways through which CD4 transmits its signal is cytoskeleton association of p56lck tyrosine kinase as well as CD4 itself. Cytoskeletal association of both proteins is inhibited by a tyrosine kinase inhibitor, genistein, indicating that tyrosine protein kinase activation is important for cytoskeletal association of CD4 and p56lck. Cytoskeletal association of these proteins by CD4 cross-linking is not affected by inhibitors of protein kinase C nor PI3-kinase. Taken together, these results suggest that CD4 cross-linking activates a tyrosine kinase which then induces the simultaneous association of CD4 and p56lck with cytoskeleton.

Keyword

T cells; cytoskeletal association; tyrosine kinase inhibition; CD4; p56 lck

MeSH Terms

Antigens, CD4/metabolism*
Antigens, CD4/drug effects
Cross-Linking Reagents
Cytoskeleton/metabolism*
Down-Regulation (Physiology)
Enzyme Inhibitors/pharmacology
Flow Cytometry
Genistein/pharmacology
Human
Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism*
Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors
Phosphorylation/drug effects
Protein Binding
Tetradecanoylphorbol Acetate/pharmacology
Tumor Cells, Cultured
Tyrosine/metabolism