title: Spastin regulates VAMP7-containing vesicles trafficking in cortical neurons.
abstract: Alteration of axonal transport has emerged as a common precipitating factor in several neurodegenerative disorders including Human Spastic Paraplegia (HSP). Mutations of the SPAST (SPG4) gene coding for the spastin protein account for 40% of all autosomal dominant uncomplicated HSP. By cleaving microtubules, spastin regulates several cellular processes depending on microtubule dynamics including intracellular membrane trafficking. Axonal transport is fundamental for the viability of motor neurons which often have very long axons and thus require efficient communication between the cell body and its periphery. Here we found that the anterograde velocity of VAMP7 vesicles, but not that of VAMP2, two vesicular-SNARE proteins implicated in neuronal development, is enhanced in SPG4-KO neurons. We showed that this effect is associated with a slight increase of the level of acetylated tubulin in SPG4-KO neurons and correlates with an enhanced activity of kinesin-1 motors. Interestingly, we demonstrated that an artificial increase of acetylated tubulin by drugs reproduces the effect of Spastin KO on VAMP7 axonal dynamics but also increased its retrograde velocity. Finally, we investigated the effect of microtubule targeting agents which rescue axonal swellings, on VAMP7 and microtubule dynamics. Our results suggest that microtubule stabilizing agents, such as taxol, may prevent the morphological defects observed in SPG4-KO neurons not simply by restoring the altered anterograde transport to basal levels but rather by increasing the retrograde velocity of axonal cargoes.
authors.affiliation: Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris-Saclay, Université d' Evry, France.
authors.forename: C
authors.initials: C
authors.lastname: Plaud
authors.affiliation: Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris-Saclay, Université d' Evry, France.
authors.forename: V
authors.initials: V
authors.lastname: Joshi
authors.affiliation: Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris-Saclay, Université d' Evry, France.
authors.forename: M
authors.initials: M
authors.lastname: Marinello
authors.affiliation: Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris-Saclay, Université d' Evry, France.
authors.forename: D
authors.initials: D
authors.lastname: Pastré
authors.affiliation: Inserm URL U950, Institut Jacques Monod, France.
authors.forename: T
authors.initials: T
authors.lastname: Galli
authors.affiliation: Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris-Saclay, Université d' Evry, France.
authors.forename: P A
authors.initials: PA
authors.lastname: Curmi
authors.affiliation: Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris-Saclay, Université d' Evry, France. Electronic address: andrea.burgo@univ-evry.fr.
authors.forename: A
authors.initials: A
authors.lastname: Burgo
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000235:genetics; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism*; D050683:R-SNARE Proteins / Q000235:genetics / Q000378:metabolism*; D022142:Secretory Vesicles / Q000235:genetics / Q000378:metabolism*; D000074181:Spastin / Q000235:genetics / Q000378:metabolism*
chemical_list: D050683:R-SNARE Proteins; C496927:Sybl1 protein, mouse; D000074181:Spastin; C498515:Spast protein, mouse
keywords: Axonal transport; Human Spastic Paraplegia; Microtubule targeting agents; SPG4; VAMP7