title: Host microtubule plus-end binding protein CLASP1 influences sequential steps in the Trypanosoma cruzi infection process.
abstract: Mammalian cell invasion by the protozoan parasite Trypanosoma cruzi involves host cell microtubule dynamics. Microtubules support kinesin-dependent anterograde trafficking of host lysosomes to the cell periphery where targeted lysosome exocytosis elicits remodelling of the plasma membrane and parasite invasion. Here, a novel role for microtubule plus-end tracking proteins (+TIPs) in the co-ordination of T. cruzi trypomastigote internalization and post-entry events is reported. Acute silencing of CLASP1, a +TIP that participates in microtubule stabilization at the cell periphery, impairs trypomastigote internalization without diminishing the capacity for calcium-regulated lysosome exocytosis. Subsequent fusion of the T. cruzi vacuole with host lysosomes and its juxtanuclear positioning are also delayed in CLASP1-depleted cells. These post-entry phenotypes correlate with a generalized impairment of minus-end directed transport of lysosomes in CLASP1 knock-down cells and mimic the effects of dynactin disruption. Consistent with GSK3β acting as a negative regulator of CLASP function, inhibition of GSK3β activity enhances T. cruzi entry in a CLASP1-dependent manner and expression of constitutively active GSK3β dampens infection. This study provides novel molecular insights into the T. cruzi infection process, emphasizing functional links between parasite-elicited signalling, host microtubule plus-end tracking proteins and dynein-based retrograde transport. Highlighted in this work is a previously unrecognized role for CLASPs in dynamic lysosome positioning, an important aspect of the nutrient sensing response in mammalian cells.
authors.affiliation: Department of Immunology and Infectious Disease, Harvard School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhao
authors.forename: Praveen
authors.initials: P
authors.lastname: Kumar
authors.forename: Sheena
authors.initials: S
authors.lastname: Shah-Simpson
authors.forename: Kacey L
authors.initials: KL
authors.lastname: Caradonna
authors.forename: Niels
authors.initials: N
authors.lastname: Galjart
authors.forename: Crystal
authors.initials: C
authors.lastname: Teygong
authors.forename: Ira
authors.initials: I
authors.lastname: Blader
authors.forename: Torsten
authors.initials: T
authors.lastname: Wittmann
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Burleigh
mesh_terms: D002478:Cells, Cultured; D004705:Endocytosis; D004847:Epithelial Cells / Q000469:parasitology; D005347:Fibroblasts / Q000469:parasitology; D020868:Gene Silencing; D054884:Host-Pathogen Interactions; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000502:physiology*; D014617:Vacuoles / Q000378:metabolism / Q000469:parasitology
chemical_list: C497850:CLASP1 protein, human; D008869:Microtubule-Associated Proteins