Vps1 in the late endosome-to-vacuole traffic

J Biosci. 2013 Mar;38(1):73-83. doi: 10.1007/s12038-012-9295-2.

Abstract

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 vps1 delta 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptor Proteins, Vesicular Transport / genetics
  • Adaptor Proteins, Vesicular Transport / metabolism
  • Endocytosis / genetics
  • Endosomal Sorting Complexes Required for Transport / genetics
  • Endosomal Sorting Complexes Required for Transport / metabolism*
  • Endosomes / metabolism*
  • Fluorescent Dyes
  • GTP-Binding Proteins / deficiency
  • GTP-Binding Proteins / genetics*
  • Gene Expression Regulation, Fungal*
  • Genes, Reporter
  • Golgi Apparatus / metabolism*
  • Green Fluorescent Proteins
  • Protein Transport / genetics
  • Pyridinium Compounds
  • Quaternary Ammonium Compounds
  • Receptors, Mating Factor / genetics
  • Receptors, Mating Factor / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction
  • Vacuoles / metabolism*
  • Vesicular Transport Proteins / deficiency
  • Vesicular Transport Proteins / genetics*

Substances

  • Adaptor Proteins, Vesicular Transport
  • Endosomal Sorting Complexes Required for Transport
  • FM 4-64
  • Fluorescent Dyes
  • Pyridinium Compounds
  • Quaternary Ammonium Compounds
  • Receptors, Mating Factor
  • STE2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • VAM6 protein, S cerevisiae
  • Vesicular Transport Proteins
  • Green Fluorescent Proteins
  • GTP-Binding Proteins
  • VPS1 protein, S cerevisiae