Restricted accumulation of phosphatidylinositol 3-kinase products in a plasmalemmal subdomain during Fc gamma receptor-mediated phagocytosis. Academic Article uri icon

Overview

abstract

  • Phagocytosis is a highly localized and rapid event, requiring the generation of spatially and temporally restricted signals. Because phosphatidylinositol 3-kinase (PI3K) plays an important role in the innate immune response, we studied the generation and distribution of 3' phosphoinositides (3'PIs) in macrophages during the course of phagocytosis. The presence of 3'PI was monitored noninvasively in cells transfected with chimeras of green fluorescent protein and the pleckstrin homology domain of either Akt, Btk, or Gab1. Although virtually undetectable in unstimulated cells, 3'PI rapidly accumulated at sites of phagocytosis. This accumulation was sharply restricted to the phagosomal cup, with little 3'PI detectable in the immediately adjacent areas of the plasmalemma. Measurements of fluorescence recovery after photobleaching were made to estimate the mobility of lipids in the cytosolic monolayer of the phagosomal membrane. Stimulation of phagocytic receptors induced a marked reduction of lipid mobility that likely contributes to the restricted distribution of 3'PI at the cup. 3'PI accumulation during phagocytosis was transient, terminating shortly after sealing of the phagosomal vacuole. Two factors contribute to the rapid disappearance of 3'PI: the dissociation of the type I PI3K from the phagosomal membrane and the persistent accumulation of phosphoinositide phosphatases.

publication date

  • June 25, 2001

Research

keywords

  • Cell Membrane Structures
  • Macrophages
  • Phagocytosis
  • Phosphatidylinositol 3-Kinases
  • Protein Serine-Threonine Kinases
  • Protein-Serine-Threonine Kinases
  • Receptors, IgG

Identity

PubMed Central ID

  • PMC2150726

Scopus Document Identifier

  • 0035954430

PubMed ID

  • 11425868

Additional Document Info

volume

  • 153

issue

  • 7