Signal transduction in neutrophil activation Phosphatidylinositol 3‐kinase is stimulated without tyrosine phosphorylation

FEBS Letters

Vlahos, Chris J.¹  Matter, William F.¹ 

[1] Cardiovascular Research, Lilly Research Laboratories, Indianapolis IN 46285-0403, USA

关键词: Neutrophil activation;    Tyrosine phosphorylation;    Phosphatidylinositol 3-kinase;    Signal transduction;    FMLP;    N-formyl-Met-Leu-Phe;    PtdIns;    phosphatidylinositol;    PDGF;    platelet-derived growth factor;    PBS;    phosphate-buffered saline;    HEPES;    4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid;    gPtdIns;    glycerophosphatidylinositol;   

DOI  :  10.1016/0014-5793(92)80781-B

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Treatment of human neutrophils with the peptide f-Met-Leu-Phe (FMLP) results in neutrophil activation concomitant with stimulation of phosphatidylinositol (PtdIns) 3-kinase activity as measured by production of PtdIns-3,4,5-P₃ in [³²P]orthophosphate labeled cells. Antiphosphotyrosine immunoprecipitates were assayed for PtdIns 3-kinase activity; essentially no activity was present in lysates from either stimulated or unstimulated cells. The 85 kDa regulatory subunit of PtdIns 3-kinase, which normally serves as a substrate for tyrosine kinases, was not detected by SDS-PAGE or Western blot analysis in antiphosphotyrosine immunoprecipitates. In addition, no radioactive band corresponding to PtdIns 3-kinase was observed by SDS-PAGE following antiPtdIns 3-kinase immunoprecipitations. However, immunoprecipitates using polyclonal antibodies against PtdIns 3-kinase showed high PtdIns 3-kinase activity in neutrophil lysates and the 85kDa subunit of PtdIns 3-kinase was detected in Western blots; no differences in activity were observed in FMLP-stimulated and unstimulated cells. These results suggest that, in contrast to polypeptide growth factor signal transduction systems, the activation of PtdIns 3-kinase by FMLP does not require tyrosine phosphorylation.

【 授权许可】

Unknown