Surface immunoglobulin-mediated signal transduction involves rapid phosphorylation and activation of the protooncogene product Raf-1 in human B-cells.
Cancer Res
; 52(3): 566-70, 1992 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-1732044
ABSTRACT
The protooncogene product, Raf-1, is a serine/threonine kinase and has been implicated as an intermediate in signal transduction mechanisms. We examined neoplastic and normal B cells for phosphorylation and activation of Raf-1 protein in response to anti-immunoglobulin antibody (anti-Ig). Anti-Ig induced rapid phosphorylation of Raf-1 protein in both neoplastic B-cells of hairy cell leukemia and normal tonsillar B-cells which proliferated well in response to anti-Ig. The increase in phosphorylation was due primarily to an increase in phosphoserine. The immune complex kinase assay using Histone V-S as an exogenous substrate also showed an increase in Raf-1-associated kinase activity. An inhibitor of protein kinase C, H7, inhibited the proliferation as well as the Raf-1 phosphorylation in response to the proliferative signal of anti-Ig. Further, downregulation of protein kinase C by the treatment with 12-phorbol 13-myristic acid significantly abrogated the induction of Raf-1 phosphorylation. These results suggest that, in human B-cells, Raf-1 protein may be involved in the signal transduction pathway mediated by surface immunoglobulin, and that it may be, at least partially, phosphorylated by activated PKC.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas Quinases
/
Linfócitos B
/
Receptores de Antígenos de Linfócitos B
/
Transdução de Sinais
/
Proteínas Proto-Oncogênicas
Limite:
Humans
Idioma:
En
Revista:
Cancer Res
Ano de publicação:
1992
Tipo de documento:
Article
País de afiliação:
Japão