Copy Link
Add to Bookmark
Report
dictyNews Volume 30 Number 17
dictyNews
Electronic Edition
Volume 30, number 17
May 30, 2008
Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.
Back issues of dictyNews, the Dicty Reference database and other
useful information is available at dictyBase - http://dictybase.org.
=========
Abstracts
=========
Giorgione, J., and Clarke, M.
Heterogeneous modes of uptake for latex beads revealed through live cell imaging of
phagocytes expressing a probe for phosphatidylinositol (3,4,5)-trisphosphate
and phosphatidylinositol (3,4)-bisphosphate.
Cell Motil. Cytoskel, in press
Latex beads are the preferred phagocytic substrate in biochemical studies of
phagosome composition and maturation. Using living Dictyostelium cells and
fluorescent probes, we compared the properties of phagosomes formed to ingest
latex beads or digestible prey. Significant differences were found during the
initial steps of phagocytosis. During uptake of bacteria or yeast, PHcrac-GFP,
a probe that binds to membranes enriched in PI(3,4,5)P3 and PI(3,4)P2, always
labeled the nascent phagosome and faded shortly after it sealed. However, labeling
of bead-containing phagosomes was highly variable. Beads were engulfed by
phagosomes either lacking or displaying the PHcrac-GFP label, and that label,
if present, often persisted for many minutes, revealing that early trafficking
steps for bead-containing phagosomes are quite heterogeneous. Later stages of
the endocytic pathway appeared more similar for phagosomes containing prey and
latex beads. Both types of phagosomes fused with acidic endosomes while
undergoing transport along microtubules, both acquired the V-ATPase and lost
it prior to exocytosis, and both bound the late endosome marker vacuolin B,
which was transferred to the plasma membrane upon exocytosis. We conclude that
caution is needed in extrapolating results from latex bead phagosomes to
phagosomes containing physiological substances, especially in early stages
of the endocytic pathway.
Submitted by: Margaret Clarke [clarkem@omrf.org]
==============================================================
[End dictyNews, volume 30, number 17]
