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https://www.ias.ac.in/article/fulltext/jbsc/038/01/0073-0083

ESCRT; FM4-64; HOPS; late endosome; traffic; vacuole; Vps1

Vacuolar protein sorting 1 (Vps1), the yeast homolog to human dynamin, is a GTP hydrolyzing protein, which plays an important role in protein sorting and targeting between the Golgi and late endosomal compartments. In this study, we assessed the functional significance of Vps1 in the membrane traffic towards the vacuole. We show here that vps1𝛥 cells accumulated FM4-64 to a greater extent than wild-type (WT) cells, suggesting slower endocytic degradation traffic toward the vacuole. In addition, we observed that two endosome-to-vacuole traffic markers, DsRed-FYVE and Ste2-GFP, were highly accumulated in Vps1-deficient cells, further supporting Vps1’s implication in efficient trafficking of endocytosed materials to the vacuole. Noteworthy, a simultaneous imaging analysis in conjunction with FM4-64 pulse-chase experiment further revealed that Vps1 plays a role in late endosome to the vacuole transport. Consistently, our subcellular localization analysis showed that Vps1 is present at the late endosome. The hyperaccumulation of endosomal intermediates in the vps1 mutant cells appears to be caused by the disruption of integrity of HOPS tethering complexes, manifested by mislocalization of Vps39 to the cytoplasm. Finally, we postulate that Vps1 functions together with the Endosomal Sorting Complex Required for Transport (ESCRT) complex at the late endosomal compartments, based on the observation that the double mutants, in which VPS1 along with singular ESCRT I, II and III genes have been disrupted, exhibited synthetic lethality. Together, we propose that Vps1 is required for correct and efficient trafficking from the late endosomal compartments to the vacuole.

Jacob Hayden¹ Michelle Williams¹ Ann Granich¹ Hyoeun Ahn¹ Brandon Tenay¹ Joshua Lukehart¹ Chad Highfill^{1 2} Sarah Dobard¹ Kyoungtae Kim¹

1. Department of Biology, Missouri State University, 901 S National, Springfield, Missouri 65807
2. Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Avenue, Lawrence, Kansas 66045

Published

March 2013

Manuscript received

19 October 2012

Accepted

12 December 2012