TI-VAMP/VAMP7 is required for optimal phagocytosis of opsonised particles in macrophages

Braun V, Fraisier V, Raposo G, Hurbain I, Sibarita JB, Chavrier P, Galli T, Niedergang F
EMBO J.. 2004-10; 23(21): 4166-76
DOI: 7600427 [pii]10.1038/sj.emboj.7600427

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Phagocytosis relies on extension of plasmalemmal pseudopods generated by focal
actin polymerisation and delivery of membranes from intracellular pools. Here we
show that compartments of the late endocytic pathway, bearing the tetanus
neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP/VAMP7), are
recruited upon particle binding and undergo exocytosis before phagosome sealing
in macrophages during Fc receptor (FcR)-mediated phagocytosis. Expression of the
dominant-negative amino-terminal domain of TI-VAMP or depletion of TI-VAMP with
small interfering RNAs inhibited phagocytosis mediated by Fc or complement
receptors. In addition, inhibition of TI-VAMP activity led to a reduced
exocytosis of late endocytic vesicles and this resulted in an early blockade of
pseudopod extension, as observed by scanning electron microscopy. Therefore,
TI-VAMP defines a new pathway of membrane delivery required for optimal
FcR-mediated phagocytosis.

DOI: 10.1038/sj.emboj.7600427
PMCID: PMC524391
PMID: 15470500

Auteurs Bordeaux Neurocampus