Cell growth-dependent coordination of lipid signaling and glycosylation is mediated by interactions between Sac1p and Dpm1p.
J Cell Biol
; 168(2): 185-91, 2005 Jan 17.
Article
em En
| MEDLINE
| ID: mdl-15657391
ABSTRACT
The integral membrane lipid phosphatase Sac1p regulates local pools of phosphatidylinositol-4-phosphate (PtdIns(4)P) at endoplasmic reticulum (ER) and Golgi membranes. PtdIns(4)P is important for Golgi trafficking, yet the significance of PtdIns(4)P for ER function is unknown. It also remains unknown how localization of Sac1p to distinct organellar membranes is mediated. Here, we show that a COOH-terminal region in yeast Sac1p is crucial for ER targeting by directly interacting with dolicholphosphate mannose synthase Dpm1p. The interaction with Dpm1p persists during exponential cell division but is rapidly abolished when cell growth slows because of nutrient limitation, causing translocation of Sac1p to Golgi membranes. Cell growth-dependent shuttling of Sac1p between the ER and the Golgi is important for reciprocal control of PtdIns(4)P levels at these organelles. The fraction of Sac1p resident at the ER is also required for efficient dolichol oligosaccharide biosynthesis. Thus, the lipid phosphatase Sac1p may be a key regulator, coordinating the secretory capacity of ER and Golgi membranes in response to growth conditions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Transdução de Sinais
/
Transporte Proteico
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Proteínas de Saccharomyces cerevisiae
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Retículo Endoplasmático
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Complexo de Golgi
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Manosiltransferases
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Proteínas de Membrana
Idioma:
En
Revista:
J Cell Biol
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Estados Unidos