CD40-triggered protein tyrosine phosphorylation on Vav and on phosphatidylinositol 3-kinase correlates with survival of the Ramos-Burkitt lymphoma B cell line

Cellular Immunology
L PadmoreK A Knox

Abstract

Signals transduced through CD40 rescue cells of the Ramos-Burkitt lymphoma (Ramos-BL) B cell line from surface immunoglobulin M (sIgM)-triggered growth arrest and apoptosis. This study investigates whether protein tyrosine kinase (PTK) activity and tyrosine phosphorylation on p95(vav) and on the p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3 kinase) play a role in the regulation of Ramos-BL B cell survival. The PTK inhibitor herbimycin A (HA) triggers significant growth arrest prior to apoptosis from the G1-phase of the cell cycle, indicating that tyrosine phosphorylation of key proteins is critical for Ramos-BL cell cycle progression and survival. Indeed, signals transduced through CD40 fail to rescue Ramos-BL B cells from HA-triggered growth arrest and apoptosis. Since Vav and PI3 kinase are intimately involved in the regulation of cellular growth, their tyrosine phosphorylation status was determined in unstimulated and anti-IgM- and anti-CD40-treated Ramos-BL B cells: Vav and p85 are devoid of tyrosine-phosphorylated epitopes in control cells whereas p85, but not Vav, is significantly phosphorylated following ligation of sIgM and anti-CD40 triggers tyrosine phosphorylation on both proteins. Thus, tyrosine-phosp...Continue Reading

References

Feb 1, 1992·Proceedings of the National Academy of Sciences of the United States of America·Y YamanashiT Yamamoto
Jan 1, 1991·Cellular Signalling·C P Downes, A N Carter
Jan 1, 1992·Immunology Today·Y J LiuI C MacLennan
Jan 25, 1991·Cell·L C CantleyS Soltoff
Jun 1, 1986·Proceedings of the National Academy of Sciences of the United States of America·D R KaplanL Cantley
Sep 15, 1989·Biochemical and Biophysical Research Communications·Y UeharaS Mizuno
Jan 1, 1980·International Review of Cytology·A H WyllieA R Currie
Sep 1, 1994·Immunology Today·F H DurieR J Noelle
Mar 12, 1993·Cell·Z SongyangR J Lechleider
Sep 1, 1994·Current Biology : CB·T KodakiP J Parker
Sep 1, 1994·Immunology Today·C M PleimanJ C Cambier
Aug 18, 1994·Nature·P Rodriguez-VicianaJ Downward
Sep 15, 1993·Biochemical and Biophysical Research Communications·F KanaiY Ebina
Jan 1, 1996·Molecular and Cellular Biology·F RomeroS Fischer

❮ Previous
Next ❯

Related Concepts

Related Feeds

AKT Pathway

This feed focuses on the AKT serine/threonine kinase, which is an important signaling pathway involved in processes such as glucose metabolism and cell survival.

Apoptosis

Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis