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Expression of the Longin domain of TI-VAMP impairs lysosomal secretion and epithelial cell migration.

Abstract : BACKGROUND INFORMATION: TI-VAMP (tetanus neurotoxin-insensitive vesicle-associated membrane protein; also called VAMP7) belongs to the Longin subfamily of v-SNAREs (vesicular soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptors). The regulatory N-terminal extension, called the Longin domain, of TI-VAMP has been shown previously to have a dual biochemical function: it inhibits the capacity of TI-VAMP to form SNARE complexes and it binds to the delta subunit of the AP-3 (adaptor protein 3) complex in early endosomes, thereby targeting TI-VAMP to late endosomes. RESULTS: We have generated MDCK (Madin-Darby canine kidney) cell lines expressing the Longin domain of TI-VAMP coupled to GFP (green fluorescent protein) in a doxycycline-dependent manner. As expected, AP-3delta (AP-3 delta subunit) is not properly localized in Longin-expressing cells. We have shown that the expression of the Longin domain impairs lysosomal secretion, as determined by the release of a pre-internalized fluorescent fluid-phase marker and by electron microscopy of the membrane-associated released particles. Membrane repair following mechanical wounding, a process requiring lysosomal secretion, is also impaired in cells expressing the Longin domain. Furthermore, cell migration, assessed by wound healing of MDCK monolayers, is also inhibited. CONCLUSIONS: The results of the present study suggest that the expression of the Longin domain of TI-VAMP regulates lysosomal secretion of epithelial cells and provide molecular evidence for a role of the late endocytic system in cell migration.
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Contributor : Martine Bondidier <>
Submitted on : Wednesday, June 6, 2007 - 11:36:03 AM
Last modification on : Tuesday, January 5, 2021 - 4:42:01 PM

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Véronique Proux-Gillardeaux, Graça Raposo, Theano Irinopoulou, Thierry Galli. Expression of the Longin domain of TI-VAMP impairs lysosomal secretion and epithelial cell migration.. Biology of the Cell, Wiley, 2007, 99 (5), pp.261-71. ⟨10.1042/BC20060097⟩. ⟨hal-00152244⟩



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