Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2002 Jul;72(1):217-21.

Rate and extent of phagocytosis in macrophages lacking vamp3

Lee-Ann H Allen  1 , Chunmei Yang, Jeffrey E Pessin
Affiliations

Rate and extent of phagocytosis in macrophages lacking vamp3

Lee-Ann H Allen et al. J Leukoc Biol. 2002 Jul.

Abstract

During phagocytosis, macrophages rapidly internalize a substantial fraction of plasma membrane without a net loss of surface area, suggesting that membranes are targeted to the cell surface from intracellular sites. Nevertheless, a requirement for mobilization of specific membrane compartments has not been demonstrated. We used bone marrow-derived macrophages (BMM) from wild type and vamp3 null mice to evaluate directly the requirement for this v-SNARE in phagocytosis of zymosan, IgG-beads, complement-opsonized particles, or latex microspheres. Regardless of the phagocytic receptor engaged or particle load, BMM lacking vamp3 exhibited no phagocytic defects when assayed after 1 h at 37 degrees C, and phagosome maturation was unimpaired as judged by acquisition of lamp-1. In contrast, at early time points (5-15 min), internalization of zymosan (but not other particles tested) was significantly slower in vamp3 null BMM. These data indicate that vamp3 modulates efficient uptake of zymosan, but is not absolutely required for phagocytosis in primary macrophages.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Vamp3 null BMM phagocytose a variety of particles. (A) vamp3 and vamp2 content of wt and mutant macrophages (KO) as judged by Western blotting of clarified lysates. (B, C) IgG-beads (IgG-B), COZ, unopsonized zymosan (Zymo), or latex beads were added to adherent wt (WT) or vamp3 null (KO) BMM, and after 1 h at 37°C, total cell-associated particles (B) and total phagosomes (C) per 100 cells were scored as described in Materials and Methods. Data shown are the average ± SD of six independent experiments conducted in triplicate.
Fig. 2
Fig. 2
Zymosan uptake is retarded in cells lacking vamp3. Phagocytosis of zymosan (A), IgG-beads (B), or COZ (C) by adherent wt or vamp3 null (KO) BMM was synchronized using centrifugation [6]. After 1–20 min at 37°C, samples were fixed and permeabilized, then stained with mAb to talin, and secondary antibodies conjugated to FITC. Graphs show the time course of talin association with forming phagosomes and are the average ± SD of four independent experiments conducted in triplicate. (●) wt BMM; (○) vamp3 null BMM. *, Statistical significance (P<0.05; Student’s t-test) relative to wt.
Fig. 3
Fig. 3
Phagocytic capacity of vamp3 null BMM is not impaired. (A) Forming zymosan phagosomes (30 s time point) are enriched for talin in wt and vamp3 null (KO) BMM (arrows). (B) One hour after addition of ~65 COZ per cell, BMM were fixed and stained with antibodies to lamp-1. Note that vamp3 null and wt BMM ingested numerous COZ as judged by phase contrast optics (lower panels) and lamp-1 fluorescence (upper panels). Arrows indicate cell margins.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Greenberg S, Silverstein SC. Phagocytosis. In: Paul WE, editor. Fundamental Immunology. New York: Raven; 1993. pp. 941–964.
    1. Hackam DJ, Rotstein OD, Sjolin C, Schreiber AD, Trimble WS, Grinstein S. v-SNARE-dependent secretion is required for phagocytosis. Proc Natl Acad Sci USA. 1998;95:11691–11696. - PMC - PubMed
    1. Cox D, Tseng CC, Bjekic G, Greenberg S. A requirement for phosphatidylinositol 3-kinase in pseudopod extension. J Biol Chem. 1999;274:1240 –1247. - PubMed
    1. Banjo L, Peng XR, Schreiber AD, Moore HP, Trimble WS, Grinstein S. Focal exocytosis of vamp3-containing vesicles at sites of phagosome formation. J Cell Biol. 2000;149:697–705. - PMC - PubMed
    1. Yang C, Mora S, Ryder JW, Coker KJ, Hansen P, Allen LA, Pessin JE. VAMP3 null mice display normal constitutive, insulin- and exercise-regulated vesicle trafficking. Mol Cell Biol. 2001;21:1573–1580. - PMC - PubMed

Publication types

LinkOut - more resources