Phagocytic signaling molecules in lipid rafts of COS-1 cells transfected with FcgammaRIIA.
Biochem Biophys Res Commun
; 331(1): 132-8, 2005 May 27.
Article
em En
| MEDLINE
| ID: mdl-15845369
ABSTRACT
COS-1 cells bearing FcgammaRIIA were used as a model to demonstrate co-localization of several enzymes previously shown to regulate neutrophil phagocytosis. In COS-1 cells, phospholipase D (PLD) in the membrane fraction was activated during phagocytosis. PLD was found almost exclusively in lipid rafts, along with RhoA and ARF1. Protein kinase C-delta (PKCdelta) and Raf-1 translocated to lipid rafts. In neutrophils, ceramide levels increase during phagocytosis, indicating that FcgammaRIIA engagement initiates ceramide generation. Applying this model, we transfected COS-1 cells with FcgammaRIIA that had been mutated in the ITAM region, rendering them unable to ingest particles. When the mutant receptors were engaged, ceramide was generated and MAPK was activated normally, thus these processes did not require actual ingestion of particles. These results indicate that signaling proteins for phagocytosis are either constitutively present in, or are recruited to, lipid rafts where they are readily available to activate one another.
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Base de dados:
MEDLINE
Assunto principal:
Fagocitose
/
Transdução de Sinais
/
Antígenos CD
/
Receptores de IgG
/
Microdomínios da Membrana
Limite:
Animals
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article