Concanavalin A modulates tyrosine phosphorylation and activation of a type II phosphatidylinositol 4-kinase in rat splenic lymphocytes.
Activation of rat splenic lymphocytes by concanavalin A resulted in two-fold increase in Ptdlns 4-kinase activity and rapid tyrosine phosphorylation of the enzyme. The activation kinetics showed a strong correlation with tyrosine phosphorylation state of the enzyme. Characterization of the enzyme activity suggests that it is a type II PtdIns 4-kinase. Kinetic analysis of the enzyme reaction showed three-fold decrease in Km for PtdIns and two-fold increase in Vmax in Con A stimulated cells. These results suggest that a type II PtdIns 4-kinase is an integral component of the early signal transduction machinery during T-cell activation by concanavalin A and is actively regulated by protein tyrosine phosphorylation-dephosphorylation.
Fernandis
A Z
AZ
Biotechnology Centre, Indian Institute of Technology, Powai, Mumbia.
Subrahmanyam
G
G
D019870:1-Phosphatidylinositol 4-Kinase / Q000378:metabolism*; D000818:Animals; D000906:Antibodies / Q000032:analysis; D003208:Concanavalin A / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000201:enzymology* / Q000276:immunology; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000276:immunology; D011233:Precipitin Tests; D017027:Protein Tyrosine Phosphatases / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000166:cytology*; D014443:Tyrosine / Q000378:metabolism*
D000906:Antibodies; D004791:Enzyme Inhibitors; D003208:Concanavalin A; D019000:Phosphotyrosine; D014443:Tyrosine; D019833:Genistein; D019870:1-Phosphatidylinositol 4-Kinase; D017027:Protein Tyrosine Phosphatases