Premium
IgG immunoglobulins induce activation of the sphingomyelin cycle in HL‐60 cells
Author(s) -
Glick Dvorah,
Barenholz Yechezkel
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00958-1
Subject(s) - sphingomyelin , chemistry , receptor , cell surface receptor , antibody , biochemistry , signal transduction , autocrine signalling , microbiology and biotechnology , tumor necrosis factor alpha , biology , membrane , immunology
In HL‐60 cells signal transduction via sphingomyelin hydrolysis (sphingomyelin cycle) is induced by binding of tumor necrosis factor α (TNFα) to cell surface TNFα receptor. We found that IgG immunoglobulins activate sphingomyelin hydrolysis in plasma membrane of HL‐60 cells, with kinetics similar to that of activation by TNFα. Activation was induced by different IgG isotypes (most of which are irrelevant to known inducers of the sphingomyelin cycle) and also by Fcγ fragments of IgG. The facts that inhibiting the binding of the antibodies to the cell surface by protein A prevents activation of sphingomyelin hydrolysis and that soluble TNF receptor of 55‐kDa subtype (TBP 55 ) inhibits activation, suggest that the mechanism of IgG‐induced sphingomyelin hydrolysis involves binding of IgGs through their Fcγ domain to Fcγ surface receptors which mediate autocrine secretion of TNFα. The latter is responsible for inducing sphingomyelin hydrolysis. This study suggests that TBP 55 may be an effective inhibitor of the sphingomyelin cycle.