title: Modular TRAPP complexes regulate intracellular protein trafficking through multiple Ypt/Rab GTPases in Saccharomyces cerevisiae.
abstract: Ypt/Rab are key regulators of intracellular trafficking in all eukaryotic cells. In yeast, Ypt1 is essential for endoplasmic reticulum (ER)-to-Golgi transport, whereas Ypt31/32 regulate Golgi-to-plasma membrane and endosome-to-Golgi transport. TRAPP is a multisubunit complex that acts as an activator of Ypt/Rab GTPases. Trs85 and Trs130 are two subunits specific for TRAPP III and TRAPP II, respectively. Whereas TRAPP III was shown to acts as a Ypt1 activator, it is still controversial whether TRAPP II acts as a Ypt1 or Ypt31/32 activator. Here, we use GFP-Snc1 as a tool to study transport in Ypt and TRAPP mutant cells. First, we show that expression of GFP-Snc1 in trs85Δ mutant cells results in temperature sensitivity. Second, we suggest that in ypt1ts and trs85Δ, but not in ypt31Δ/32ts and trs130ts mutant cells, GFP-Snc1 accumulates in the ER. Third, we show that overexpression of Ypt1, but not Ypt31/32, can suppress both the growth and GFP-Snc1 accumulation phenotypes of trs85Δ mutant cells. In contrast, overexpression of Ypt31, but not Ypt1, suppresses the growth and GFP-Snc1 transport phenotypes of trs130ts mutant cells. These results provide genetic support for functional grouping of Ypt1 with Trs85-containing TRAPP III and Ypt31/32 with Trs130-containing TRAPP II.
authors.affiliation: College of Life Sciences, Key Laboratory for Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
authors.forename: Shenshen
authors.initials: S
authors.lastname: Zou
authors.forename: Yutao
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiu Qi
authors.initials: XQ
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Ye
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhu
authors.forename: Shu
authors.initials: S
authors.lastname: Yang
authors.forename: Zhanna
authors.initials: Z
authors.lastname: Lipatova
authors.forename: Yongheng
authors.initials: Y
authors.lastname: Liang
authors.forename: Nava
authors.initials: N
authors.lastname: Segev
mesh_terms: D004721:Endoplasmic Reticulum / Q000378:metabolism; D015870:Gene Expression; D009154:Mutation; D021381:Protein Transport; D050683:R-SNARE Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D050683:R-SNARE Proteins; C083241:SNC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; C406327:transport protein particle, TRAPP; C060755:YPT1 protein, S cerevisiae; D020691:rab GTP-Binding Proteins