A role for PKC-epsilon in Fc gamma R-mediated phagocytosis by RAW 264.7 cells

TY - JOUR

T1 - A role for PKC-epsilon in Fc gamma R-mediated phagocytosis by RAW 264.7 cells

AU - Larsen, EC

AU - Ueyama, T

AU - Brannock, PM

AU - Shirai, Y

AU - Saito, N

AU - Larsson, Christer

AU - Loegering, D

AU - Weber, PB

AU - Lennartz, MR

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Tumour Cell Biology (013017530)

PY - 2002

Y1 - 2002

N2 - Protein kinase C (PKC) plays a prominent role in immune signaling, and the paradigms for isoform selective signaling are beginning to be elucidated. Real-time microscopy was combined with molecular and biochemical approaches to demonstrate a role for PKC-epsilon in Fcgamma receptor (FcgammaR)-dependent phagocytosis. RAW 264.7 macrophages were transfected with GFP-conjugated PKC isoforms, and GFP movement was followed during phagocytosis of fluorescent IgG-opsonized beads. PKC-epsilon, but not PKC-delta, concentrated around the beads. PKC-epsilon accumulation was transient; apparent as a "flash" on target ingestion. Similarly, endogenous PKC-epsilon was specifically recruited to the nascent phagosomes in a time-dependent manner. Overexpression of PKC-epsilon, but not PKC-alpha, PKC-delta, or PKC-gamma enhanced bead uptake 1.8-fold. Additionally, the rate of phagocytosis in GFP PKC-epsilon expressors was twice that of cells expressing GFP PKC-delta. Expression of the regulatory domain (ERD) and the first variable region (epsilonV1) of PKC-epsilon inhibited uptake, whereas the corresponding PKC-delta region had no effect. Actin polymerization was enhanced on expression of GFP PKC-epsilon and ERD, but decreased in cells expressing epsilonV1, suggesting that the epsilonRD and epsilonV1 inhibition of phagocytosis is not due to effects on actin polymerization. These results demonstrate a role for PKC-epsilon in FcgammaR-mediated phagocytosis that is independent of its effects on actin assembly.

AB - Protein kinase C (PKC) plays a prominent role in immune signaling, and the paradigms for isoform selective signaling are beginning to be elucidated. Real-time microscopy was combined with molecular and biochemical approaches to demonstrate a role for PKC-epsilon in Fcgamma receptor (FcgammaR)-dependent phagocytosis. RAW 264.7 macrophages were transfected with GFP-conjugated PKC isoforms, and GFP movement was followed during phagocytosis of fluorescent IgG-opsonized beads. PKC-epsilon, but not PKC-delta, concentrated around the beads. PKC-epsilon accumulation was transient; apparent as a "flash" on target ingestion. Similarly, endogenous PKC-epsilon was specifically recruited to the nascent phagosomes in a time-dependent manner. Overexpression of PKC-epsilon, but not PKC-alpha, PKC-delta, or PKC-gamma enhanced bead uptake 1.8-fold. Additionally, the rate of phagocytosis in GFP PKC-epsilon expressors was twice that of cells expressing GFP PKC-delta. Expression of the regulatory domain (ERD) and the first variable region (epsilonV1) of PKC-epsilon inhibited uptake, whereas the corresponding PKC-delta region had no effect. Actin polymerization was enhanced on expression of GFP PKC-epsilon and ERD, but decreased in cells expressing epsilonV1, suggesting that the epsilonRD and epsilonV1 inhibition of phagocytosis is not due to effects on actin polymerization. These results demonstrate a role for PKC-epsilon in FcgammaR-mediated phagocytosis that is independent of its effects on actin assembly.

KW - immunoglobulin

KW - protein kinase C-epsilon

KW - signal transduction

KW - macrophage

KW - confocal

U2 - 10.1083/jcb.200205140

DO - 10.1083/jcb.200205140

M3 - Article

C2 - 12499353

VL - 159

SP - 939

EP - 944

JO - Journal of Cell Biology

JF - Journal of Cell Biology

SN - 0021-9525

IS - 6

ER -