Residues Y429 and Y463 of the human CD5 are targeted by protein tyrosine kinases

• Published in: European journal of immunology 2001-04, Vol.31 (4), p.1191-1198
• Main Authors: Vilà, Josep M., Gimferrer, Idoia, Padilla, Olga, Arman, Mònica, Places, Lourdes, Simarro, María, Vives, Jordi, Lozano, Francisco
• Format: Article
• Language: English
• Subjects: Amino Acid Substitution - genetics; Antibodies, Monoclonal - immunology; Antibodies, Monoclonal - pharmacology; CD3 Complex - genetics; CD3 Complex - immunology; CD5 antigen; CD5 Antigens - chemistry; CD5 Antigens - genetics; CD5 Antigens - metabolism; Enzyme Activation - drug effects; Fyn; Human CD5; Humans; Jurkat Cells; Lck; Lck protein; Lymphocyte activation; Lymphocyte Activation - drug effects; Lymphocyte Specific Protein Tyrosine Kinase p56(lck) - deficiency; Lymphocyte Specific Protein Tyrosine Kinase p56(lck) - genetics; Lymphocyte Specific Protein Tyrosine Kinase p56(lck) - metabolism; Mutation - genetics; Phosphorylation - drug effects; Phosphotyrosine - metabolism; Protein Tyrosine Phosphatases - antagonists & inhibitors; Protein-Tyrosine Kinases - deficiency; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-fyn; Recombinant Fusion Proteins - metabolism; T-Lymphocytes - drug effects; T-Lymphocytes - enzymology; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; Transfection; Tyrosine - genetics; Tyrosine - metabolism; Tyrosine phosphorylation; Vanadates - pharmacology
• ISSN: 0014-2980; 1521-4141
• DOI: 10.1002/1521-4141(200104)31:4<1191::AID-IMMU1191>3.0.CO;2-H

The human CD5 lymphocyte cell surface co‐receptor modulates activation and differentiation responses mediated by the antigen‐specific receptor of T and B cells. CD5 is phosphorylated followinglymphocyte activation; however, the exact sites and kinases involved are yet to be determined. Jurkat T cell transfectants expressing tyrosine‐mutated CD5 molecules have been used to show that residues Y429 and Y463 are targeted in vivo by protein tyrosine kinases following cell stimulation with anti‐CD3 mAb or pervanadate. This is in agreement with data from direct in vitrokinase assays using purified recombinant Lck and Fyn protein tyrosine kinases. The analysis of Lck‐ and CD3‐deficient Jurkat cells shows that tyrosine phosphorylation of CD5 requires Lck activity. We propose that T cell activation mediates CD5 tyrosine phosphorylation at residues Y429 and Y463 mainly through the activation of Lck.