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Growth Control of Golgi Phosphoinositides by Reciprocal Localization of Sac1 Lipid Phosphatase and Pik1 4‐Kinase
Author(s) -
Faulhammer Frank,
KanjilalKolar Suparna,
Knödler Andreas,
Lo Jennifer,
Lee Yerim,
Konrad Gerlinde,
Mayinger Peter
Publication year - 2007
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2007.00632.x
Subject(s) - golgi apparatus , biology , microbiology and biotechnology , endoplasmic reticulum , phosphatidylinositol , phosphatase , kinase , biochemistry , phosphorylation
Compartment‐specific control of phosphoinositide lipids is essential for cell function. The Sac1 lipid phosphatase regulates endoplasmic reticulum (ER) and Golgi phosphatidylinositol‐4‐phosphate [PI(4)P] in response to nutrient levels and cell growth stages. During exponential growth, Sac1p interacts with Dpm1p at the ER but shuttles to the Golgi during starvation. Here, we report that a C‐terminal region in Sac1p is required for retention in the perinuclear ER, whereas the N‐terminal domain is responsible for Golgi localization. We also show that starvation‐induced shuttling of Sac1p to the Golgi depends on the coat protein complex II and the Rer1 adaptor protein. Starvation‐induced shuttling of Sac1p to the Golgi specifically eliminates a pool of PI(4)P generated by the lipid kinase Pik1p. In addition, absence of nutrients leads to a rapid dissociation of Pik1p, together with its non‐catalytical subunit Frq1p, from Golgi membranes. Reciprocal rounds of association/dissociation of the Sac1p lipid phosphatase and the Pik1p/Frq1p lipid kinase complex are responsible for growth‐dependent control of Golgi phosphoinositides. Sac1p and Pik1p/Frq1p are therefore elements of a unique machinery that synchronizes ER and Golgi function in response to different growth conditions.