EBV increases phosphoinositide kinase activities in human B cells.
To determine whether EBV affects phosphoinositide kinase activities of human B cells, we compared the activities between EBV- and EBV+ human B cell lymphoma lines. The two types of human B cells contained both phosphatidylinositol (PtdIns) 4-kinase and phosphatidylinositol 4-phosphate (PtdIns(4)P) kinase activities irrespective of the presence of EBV. However, both activities were increased in EBV+ cells compared to EBV- cells. The increases were associated with neither altered Km values for substrates nor altered elution profiles in DEAE-cellulose chromatography. Furthermore, expression of a latent EBV protein, EBV nuclear Ag1 (EBNA1) in BHK cells by the transfection of EBNA1 DNA was accompanied by increased PtdIns 4-kinase and PtdIns(4)P kinase activities. These increases also were not associated with altered Km values for substrates. However, phospholipase C activity was altered in neither EBV+ cells nor in EBNA1-expressing cells. These results indicate that EBV selectively increases the two phosphoinositide kinase activities in human B cells, although the viral gene product has no intrinsic phosphoinositide kinase activity. PtdIns 4-kinase and PtdIns(4)P kinase cooperatively synthesize PtdIns 4,5-bisphosphate, the major source of 1,2-diacylglycerol and inositol 1,4,5-triphosphate, the two second messengers in transducing signals for cell activation. Such increase therefore may play a role in EBV-induced human B cell activation.
Suzuki
Y
Y
Department of Microbiology, Nihon University School of Medicine, Tokyo, Japan.
Ohsugi
K
K
Ono
Y
Y
D019870:1-Phosphatidylinositol 4-Kinase; D000956:Antigens, Viral / Q000235:genetics; D001402:B-Lymphocytes / Q000502:physiology*; D002478:Cells, Cultured; D019309:Epstein-Barr Virus Nuclear Antigens; D004854:Herpesvirus 4, Human; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008213:Lymphocyte Activation; D010770:Phosphotransferases / Q000378:metabolism*; D014162:Transfection; D014412:Tumor Virus Infections / Q000201:enzymology*; D010738:Type C Phospholipases / Q000378:metabolism
D000956:Antigens, Viral; D019309:Epstein-Barr Virus Nuclear Antigens; D010770:Phosphotransferases; D019870:1-Phosphatidylinositol 4-Kinase; D010738:Type C Phospholipases