TRPV2 has a pivotal role in macrophage particle binding and phagocytosis

Abstract

Phagocytosis involves ionic flux, but the identity of the ion channels involved remains ill defined. Caterina and co-workers show that the cation channel TRPV2 is involved in particle binding and phagocytosis in macrophages. Macrophage phagocytosis is critical for defense against pathogens. Whereas many steps of phagocytosis involve ionic flux, the underlying ion channels remain ill defined. Here we show that zymosan-, immunoglobulin G (IgG)- and complement-mediated particle binding and phagocytosis were impaired in macrophages lacking the cation channel TRPV2. TRPV2 was recruited to the nascent phagosome and depolarized the plasma membrane. Depolarization increased the synthesis of phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2), which triggered the partial actin depolymerization necessary for occupancy-elicited phagocytic receptor clustering. TRPV2-deficient macrophages were also defective in chemoattractant-elicited motility. Consequently, TRPV2-deficient mice showed accelerated mortality and greater organ bacterial load when challenged with Listeria monocytogenes. Our data demonstrate the participation of TRPV2 in early phagocytosis and its fundamental importance in innate immunity.