Yvonne Gloor

Publications (4)18.97 Total impact

• Article: Co-regulation of the arf-activation cycle and phospholipid-signaling during golgi maturation.

  Yvonne Gloor, Thomas Müller-Reichert, Christiane Walch-Solimena
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  ABSTRACT: The Golgi apparatus is the central protein sorting station inside eukaryotic cells. Although many regulators of Golgi trafficking have been identified, little is known about their crosstalk. Both the Arf activation cycle and phosphatidylinositol 4-phosphate metabolism have been recognized as key processes in the regulation of vesicular transport from this organelle. However, the mechanism ensuring the proper co-regulation of these processes has eluded our understanding thus far. We recently identified a physical interaction between the late yeast Golgi Arf activator Sec7p and the PI4-kinase Pik1p, and showed that the two proteins cooperate in the formation of clathrin-coated vesicles. This finding gives the first insight on the coordinated generation of a dual key signal by a small GTPase and a signaling phospholipid at the Golgi. In addition, it opens new perspectives for a better understanding of Golgi maturation through coordinated regulation of highly dynamic lipid and protein composition of this organelle.
  Communicative & integrative biology 01/2012; 5(1):12-5.
• Article: Interaction between Sec7p and Pik1p: the first clue for the regulation of a coincidence detection signal.

  Yvonne Gloor, Mario Schöne, Bianca Habermann, Ebru Ercan, Mike Beck, Grit Weselek, Thomas Müller-Reichert, Christiane Walch-Solimena
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  ABSTRACT: Sec7p, a guanine nucleotide exchange factor, regulates the activation of small Arf GTPases, which function in the formation of distinct classes of transport carriers from the Golgi. The recruitment of a subset of Arf effectors depends on the cooperation between these GTPases and phosphatidylinositol 4-phosphate. Here, we show that the catalytic domain of Sec7p interacts with a conserved region of the Golgi phosphatidylinositol 4-kinase Pik1p. We found that Sec7p and Pik1p as well as its product, colocalize at the late Golgi. Gea1p/Gea2p, an alternative pair of Arf activators, do not bind to Pik1p and function on a different Golgi sub-compartment. Sec7p and Pik1p interact with each other and cooperate in the formation of clathrin-coated vesicles. This interaction reveals a distinct role for Sec7p among the Golgi Arf-GEFs and provides a working model for the coordinated generation of Arf-GTP and phosphatiylinositol 4-phosphate as dual signal for specific recruitment of clathrin coats to the late Golgi.
  European journal of cell biology 08/2010; 89(8):575-83. · 3.31 Impact Factor
• Source

  Available from: Jan Havliš

  Article: Nucleocytoplasmic shuttling of the Golgi phosphatidylinositol 4-kinase Pik1 is regulated by 14-3-3 proteins and coordinates Golgi function with cell growth.

  Lars Demmel, Mike Beck, Christian Klose, Anne-Lore Schlaitz, Yvonne Gloor, Peggy P Hsu, Jan Havlis, Andrej Shevchenko, Eberhard Krause, Yannis Kalaidzidis, Christiane Walch-Solimena
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  ABSTRACT: The yeast phosphatidylinositol 4-kinase Pik1p is essential for proliferation, and it controls Golgi homeostasis and transport of newly synthesized proteins from this compartment. At the Golgi, phosphatidylinositol 4-phosphate recruits multiple cytosolic effectors involved in formation of post-Golgi transport vesicles. A second pool of catalytically active Pik1p localizes to the nucleus. The physiological significance and regulation of this dual localization of the lipid kinase remains unknown. Here, we show that Pik1p binds to the redundant 14-3-3 proteins Bmh1p and Bmh2p. We provide evidence that nucleocytoplasmic shuttling of Pik1p involves phosphorylation and that 14-3-3 proteins bind Pik1p in the cytoplasm. Nutrient deprivation results in relocation of Pik1p from the Golgi to the nucleus and increases the amount of Pik1p-14-3-3 complex, a process reversed upon restored nutrient supply. These data suggest a role of Pik1p nucleocytoplasmic shuttling in coordination of biosynthetic transport from the Golgi with nutrient signaling.
  Molecular biology of the cell 04/2008; 19(3):1046-61. · 5.98 Impact Factor
• Source

  Available from: ncbi.nlm.nih.gov

  Article: A genome-wide visual screen reveals a role for sphingolipids and ergosterol in cell surface delivery in yeast.

  Tomasz J Proszynski, Robin W Klemm, Maike Gravert, Peggy P Hsu, Yvonne Gloor, Jan Wagner, Karol Kozak, Hannes Grabner, Karen Walzer, Michel Bagnat, Kai Simons, Christiane Walch-Solimena
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  ABSTRACT: Recently synthesized proteins are sorted at the trans-Golgi network into specialized routes for exocytosis. Surprisingly little is known about the underlying molecular machinery. Here, we present a visual screen to search for proteins involved in cargo sorting and vesicle formation. We expressed a GFP-tagged plasma membrane protein in the yeast deletion library and identified mutants with altered marker localization. This screen revealed a requirement of several enzymes regulating the synthesis of sphingolipids and ergosterol in the correct and efficient delivery of the marker protein to the cell surface. Additionally, we identified mutants regulating the actin cytoskeleton (Rvs161p and Vrp1p), known membrane traffic regulators (Kes1p and Chs5p), and several unknown genes. This visual screening method can now be used for different cargo proteins to search in a genome-wide fashion for machinery involved in post-Golgi sorting.
  Proceedings of the National Academy of Sciences 01/2006; 102(50):17981-6. · 9.68 Impact Factor