Ca{sup 2+}-dependent mobility of vesicles capturing anti-VGLUT1 antibodies

Journal Article · Thu Nov 01 00:00:00 EDT 2007 · Experimental Cell Research

DOI:https://doi.org/10.1016/j.yexcr.2007.08.020· OSTI ID:21045902

Stenovec, Matjaz ^[1]; Kreft, Marko ^[1]; Grilc, Sonja ^[1]; Potokar, Maja ^[1]; Pangrsic, Tina ^[2]; Zorec, Robert ^[1]

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1. Celica Biomedical Center, Proletarska 4, 1000 Ljubljana (Slovenia)
2. Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana (Slovenia)

Several aspects of secretory vesicle cycle have been studied in the past, but vesicle trafficking in relation to the fusion site is less well understood. In particular, the mobility of recaptured vesicles that traffic back toward the central cytoplasm is still poorly defined. We exposed astrocytes to antibodies against the vesicular glutamate transporter 1 (VGLUT1), a marker of glutamatergic vesicles, to fluorescently label vesicles undergoing Ca{sup 2+}-dependent exocytosis and examined their number, fluorescence intensity, and mobility by confocal microscopy. In nonstimulated cells, immunolabeling revealed discrete fluorescent puncta, indicating that VGLUT1 vesicles, which are approximately 50 nm in diameter, cycle slowly between the plasma membrane and the cytoplasm. When the cytosolic Ca{sup 2+} level was raised with ionomycin, the number and fluorescence intensity of the puncta increased, likely because the VGLUT1 epitopes were more accessible to the extracellularly applied antibodies following Ca{sup 2+}-triggered exocytosis. In nonstimulated cells, the mobility of labeled vesicles was limited. In stimulated cells, many vesicles exhibited directional mobility that was abolished by cytoskeleton-disrupting agents, indicating dependence on intact cytoskeleton. Our findings show that postfusion vesicle mobility is regulated and may likely play a role in synaptic vesicle cycle, and also more generally in the genesis and removal of endocytic vesicles.

• OSTI ID: 21045902
• Journal Information: Experimental Cell Research, Vol. 313, Issue 18; Other Information: DOI: 10.1016/j.yexcr.2007.08.020; PII: S0014-4827(07)00408-9; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANTIBODIES
CALCIUM IONS
CELL MEMBRANES
CYTOPLASM
FLUORESCENCE
MICROTUBULES