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EBV increases phosphoinositide kinase activities in human B cells
1Department of Microbiology, Nihon University School of Medicine, Tokyo, Japan.
Journal of Immunology (Baltimore, Md. : 1950)
|July 1, 1992
Summary
Epstein-Barr virus (EBV) increases phosphatidylinositol (PtdIns) 4-kinase and phosphatidylinositol 4-phosphate (PtdIns(4)P) kinase activities in human B cells. This viral effect on phosphoinositide kinases may drive B cell activation.
Area of Science:
- Cell Biology
- Virology
- Biochemistry
Background:
- Epstein-Barr virus (EBV) is a human herpesvirus linked to various B cell malignancies.
- Phosphoinositide kinases play crucial roles in cellular signaling pathways.
Purpose of the Study:
- To investigate the impact of EBV infection on phosphoinositide kinase activities in human B cells.
- To determine if EBV nuclear antigen 1 (EBNA1) influences these kinase activities.
Main Methods:
- Comparative analysis of phosphatidylinositol (PtdIns) 4-kinase and phosphatidylinositol 4-phosphate (PtdIns(4)P) kinase activities in EBV-positive (EBV+) and EBV-negative (EBV-) human B cell lines.
- Enzyme kinetics (Km values) and ion-exchange chromatography were used to characterize kinase activities.
- Transfection of EBNA1 DNA into BHK cells to assess its effect on kinase activities.
Main Results:
- Both PtdIns 4-kinase and PtdIns(4)P kinase activities were present in EBV+ and EBV- cells but were elevated in EBV+ cells.
- Increased kinase activities in EBV+ cells and EBNA1-expressing cells were not associated with altered substrate Km values.
- Phospholipase C activity remained unchanged in both EBV+ and EBNA1-expressing cells.
Conclusions:
- EBV selectively enhances PtdIns 4-kinase and PtdIns(4)P kinase activities in human B cells.
- The viral protein EBNA1 contributes to the observed increase in kinase activities.
- These elevated phosphoinositide kinase activities may be involved in EBV-mediated human B cell activation.