title: Differential use of endoplasmic reticulum membrane for phagocytosis in J774 macrophages.
abstract: Sustained phagocytosis requires the continuous replacement of cell-surface membrane from intracellular sources. Depending on the nature of the engulfed particles, a variety of endocytic compartments have been demonstrated to contribute membranes needed for the formation of phagosomes. It has recently been reported that the endoplasmic reticulum (ER) can also fuse with the plasma membrane during phagocytosis [Gagnon, E., Duclos, S., Rondeau, C., Chevet, E., Cameron, P. H., Steele-Mortimer, O., Paiement, J., Bergeron, J. J. & Desjardins, M. (2002) Cell 110, 119-131]. However, there is currently no known mechanistic basis for this fusion process to occur. Here we report that direct ER-plasma membrane fusion during phagocytosis requires the ER resident soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein ERS24/Sec22b and that J774-macrophages react toward the challenge of large (3.0-microm) but not small (0.8-microm) particles by triggering this fusion mechanism, allowing them to access the most abundant endogenous membrane source in the cell, the ER.
authors.affiliation: Department of Physiology and Cellular Biophysics, Russ Berrie Medical Science Pavilion, Columbia University, 1150 St. Nicholas Avenue, New York, NY 10032, USA.
authors.forename: Thalia
authors.initials: T
authors.lastname: Becker
authors.forename: Allen
authors.initials: A
authors.lastname: Volchuk
authors.forename: James E
authors.initials: JE
authors.lastname: Rothman
mesh_terms: D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000502:physiology*; D006056:Golgi Apparatus / Q000187:drug effects; D008264:Macrophages / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D050683:R-SNARE Proteins; D033921:Vesicular Transport Proteins / Q000502:physiology
chemical_list: C106334:ERS-24 protein, Cricetulus griseus; D008565:Membrane Proteins; D011500:Protein Synthesis Inhibitors; D050683:R-SNARE Proteins; C432415:Sec22b protein, mouse; D033921:Vesicular Transport Proteins; D020126:Brefeldin A