Tyrosine phosphorylation of phospholipase C induced by membrane immunoglobulin in B lymphocytes. Academic Article uri icon

Overview

abstract

  • Ligation of membrane IgM on B lymphocytes causes activation of a protein-tyrosine kinase(s) (PTK) and of phospholipase C (PLC). To determine whether these are elements of a common signal-transduction pathway, the effect of three PTK inhibitors on the rise in intracellular free Ca2+ concentration [( Ca2+]i) in human B-lymphoblastoid cell lines was assessed. Tyrphostin completely suppressed the increase in [Ca2+]i and the generation of inositol phosphates induced by ligation of membrane immunoglobulin (mIg) M. Herbimycin and genistein reduced by 30% and 50%, respectively, the rise in [Ca2+]i caused by optimal ligation of mIgM, and they abolished it in cells activated by suboptimal ligation of mIgM. Tyrphostin had no effect on the capacity of aluminum fluoride to increase [Ca2+]i. To determine whether a function of PTK is the phosphorylation of PLC, immunoprecipitates obtained with anti-phosphotyrosine from detergent lysates of B-lymphoblastoid cells were assayed for PLC activity. Ligation of mIgM increased immunoprecipitable PLC activity 2-fold by 90 sec and 4-fold by 30 min. Specific immunoprecipitation and Western blot analysis identified tyrosine phosphorylation of the gamma 1 isoform of PLC after 60 sec of stimulation. Activation of PLC in B cells by mIgM requires PTK function and is associated with tyrosine phosphorylation of PLC-gamma 1, suggesting a mechanism of PLC activation similar to that described for certain receptor PTKs.

publication date

  • April 1, 1991

Research

keywords

  • Aluminum Compounds
  • B-Lymphocytes
  • Immunoglobulin M
  • Quinones
  • Receptors, Antigen, B-Cell
  • Type C Phospholipases
  • Tyrosine

Identity

PubMed Central ID

  • PMC51315

Scopus Document Identifier

  • 0025849698

Digital Object Identifier (DOI)

  • 10.1073/pnas.88.7.2745

PubMed ID

  • 2011584

Additional Document Info

volume

  • 88

issue

  • 7