Confocal imaging and tracking of the exocytotic routes for D-serine-mediated gliotransmission.
Glia. 2008-09-01; 56(12): 1271-1284
DOI: 10.1002/glia.20696
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1. Glia. 2008 Sep;56(12):1271-84. doi: 10.1002/glia.20696.
Confocal imaging and tracking of the exocytotic routes for D-serine-mediated
gliotransmission.
Martineau M(1), Galli T, Baux G, Mothet JP.
Author information:
(1)CNRS, Institut de Neurobiologie Alfred Fessard, FRC 2118, Laboratoire de
Neurobiologie Cellulaire et Moléculaire, UPR 9040, F-91198 Gif-sur-Yvette,
France.
D-Serine is an astrocyte-derived regulator for N-methyl-D-aspartate receptors,
but the intracellular routes of its trafficking are still largely unknown. Here,
we combined confocal microscopy with colocalization quantification to track the
astrocytic organelles that store D-serine. We report that D-serine colocalizes
with the transfected eGFP-synaptobrevin/VAMP2 and eGFP-cellubrevin/VAMP3, two
v-SNAREs of the regulated secretory pathway. No significant colocalization was
found with markers of the endosomal sorting and recycling system: EEA1,
eGFP-endobrevin/VAMP8, eGFP-TI-VAMP/VAMP7, LAMP1, and CD63. Blockade of vesicular
budding with colchicine shows that secretory vesicles import D-serine downstream
to the Golgi apparatus. Finally, treatment of astrocytes with the Ca2+-ionophore
A23187, glutamate agonists, or bradykinin trigger translocation of
synaptobrevin/VAMP2 to the plasma membrane with a concomitant disappearance of
D-serine from the regulated secretory pathway. Our results provide morphological
evidence for a vesicular storage of D-serine in the regulated secretory pathway
and the possible recruitment of these stores by Ca2+ mobilization to release
D-serine.
(c) 2008 Wiley-Liss, Inc.
DOI: 10.1002/glia.20696
PMID: 18615566 [Indexed for MEDLINE]