Kinesin 5B is necessary for delivery of membrane and receptors during FcγR-mediated phagocytosis

J Immunol. 2011 Jan 15;186(2):816-25. doi: 10.4049/jimmunol.1002161. Epub 2010 Dec 13.

Abstract

FcγR-mediated phagocytosis is a cellular event that is evolutionary conserved to digest IgG-opsonized pathogens. Pseudopod formation during phagocytosis is a limiting step in managing the uptake of particles, and in this paper, we show that the conventional kinesin is involved in both receptor and membrane delivery to the phagocytic cup. Expression of a mutant kinesin isoform (GFP dominant negative mutant of kinesin H chain [EGFP-Kif5B-DN]) in RAW264.7 cells significantly reduced binding of IgG-sheep RBCs when macrophages were faced with multiple encounters with opsonized particles. Scanning electron microscopy analysis of EGFP-Kif5B-DN-expressing cells challenged with two rounds of IgG-sheep RBCs showed sparse, extremely thin pseudopods. We saw disrupted Rab11 trafficking to the phagocytic cup in EGFP-Kif5B-DN-transfected cells. Our particle overload assays also implicated phagosome membrane recycling in pseudopod formation. We observed reduced phagosome fission and trafficking in mutant kinesin-expressing cells, as well as reduced cell surface expression of FcγRs and Mac-1 receptors. In conclusion, anterograde trafficking via kinesin is essential for both receptor recycling from the phagosome and delivery of Rab11-containing membrane stores to effect broad and functional pseudopods during FcγR-mediated phagocytosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Polarity / genetics
  • Cell Polarity / immunology
  • Down-Regulation / genetics
  • Down-Regulation / immunology
  • Exocytosis / genetics
  • Exocytosis / immunology
  • Intracellular Membranes / enzymology*
  • Intracellular Membranes / immunology*
  • Intracellular Membranes / ultrastructure
  • Kinesins / genetics
  • Kinesins / physiology*
  • Kinesins / ultrastructure
  • Mice
  • Phagocytosis / genetics
  • Phagocytosis / immunology*
  • Phagosomes / enzymology
  • Phagosomes / immunology
  • Phagosomes / ultrastructure
  • Protein Binding / genetics
  • Protein Binding / immunology
  • Protein Transport / genetics
  • Protein Transport / immunology
  • Pseudopodia / enzymology
  • Pseudopodia / immunology
  • Pseudopodia / ultrastructure
  • Receptors, IgG / metabolism*
  • Receptors, IgG / physiology
  • Receptors, IgG / ultrastructure
  • SNARE Proteins / metabolism*
  • SNARE Proteins / ultrastructure
  • Signal Transduction / genetics
  • Signal Transduction / immunology
  • Transfection
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism
  • rab GTP-Binding Proteins / ultrastructure

Substances

  • Receptors, IgG
  • SNARE Proteins
  • Kif5b protein, mouse
  • rab11 protein
  • Kinesins
  • rab GTP-Binding Proteins