Ceramide synthesis enhances transport of GPI-anchored proteins to the Golgi apparatus in yeast.

Horváth, Anton; Sütterlin, Christine; Manning-Krieg, Ute C.; Movva, N. Rao; Riezman, Howard

doi:10.1002/j.1460-2075.1994.tb06678.x

Cited by 211 publications

(198 citation statements)

References 39 publications

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“…The transport of GPI-anchored proteins from the ER to the Golgi requires ongoing sphingoid base and/or ceramide synthesis (Horvath et al, 1994;Skrzypek et al, 1997;Sutterlin et al, 1997). Barz and Walter (1999) raised the possibility that the reduction in kinetics of GPI-anchored protein transport to the Golgi compartment in the lag1⌬lac1⌬ deletion strain could be due to an alteration in sphingolipid biosynthesis.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, a lag1⌬lac1⌬ strain showed an ϳ50% reduction in the rate of transport of glycosylphosphatidylinositol (GPI)-anchored proteins to the Golgi, whereas the maturation of non-GPIanchored proteins was unaltered. Because transport of GPIanchored proteins requires ongoing sphingoid base synthesis (Horvath et al, 1994;Muniz et al, 2001), we decided to analyze sphingolipid biosynthesis in the lag1⌬lac1⌬ deletion strain. By combination of in vivo and in vitro approaches, we demonstrate that Lag1p and Lac1p are essential for the acyl-CoA-dependent and FB1-sensitive ceramide synthase reaction.…”

Section: Introductionmentioning

confidence: 99%

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Lag1p and Lac1p Are Essential for the Acyl-CoA–dependent Ceramide Synthase Reaction inSaccharomyces cerevisae

Schorling

Vallée

Barz

et al. 2001

MBoC

268

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Lag1p and Lac1p are two homologous transmembrane proteins of the endoplasmic reticulum in Saccharomyces cerevisiae. Homologous genes have been found in a wide variety of eukaryotes. In yeast, both genes, LAC1 and LAG1, are required for efficient endoplasmic reticulum-to-Golgi transport of glycosylphosphatidylinositol-anchored proteins. In this study, we show that lag1⌬lac1⌬ cells have reduced sphingolipid levels due to a block of the fumonisin B1-sensitive and acyl-CoA-dependent ceramide synthase reaction. The sphingolipid synthesis defect in lag1⌬lac1⌬ cells can be partially corrected by overexpression of YPC1 or YDC1, encoding ceramidases that have been reported to have acyl-CoA-independent ceramide synthesis activity. Quadruple mutant cells (lag1⌬lac1⌬ypc1⌬ydc1⌬) do not make any sphingolipids, but are still viable probably because they produce novel lipids. Moreover, lag1⌬lac1⌬ cells are resistant to aureobasidin A, an inhibitor of the inositolphosphorylceramide synthase, suggesting that aureobasidin A may be toxic because it leads to increased ceramide levels. Based on these data, LAG1 and LAC1 are the first genes to be identified that are required for the fumonisin B1-sensitive and acyl-CoAdependent ceramide synthase reaction.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lag1p and Lac1p Are Essential for the Acyl-CoA–dependent Ceramide Synthase Reaction inSaccharomyces cerevisae

Schorling

Vallée

Barz

et al. 2001

MBoC

268

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“…For example, in GPI-deficient mutants generated by the heterologous expression of Trypanosoma brucei GPI-PLC, of four proteins that normally are GPI anchored in Trypanosoma cruzi, two were secreted prematurely and the other two were degraded intracellularly (Garg et al, 1997). GAPs that are transferred incompletely to the GPI anchor in yeast are retained in the endoplasmic reticulum and degraded (Horvath et al, 1994). The fate of GPI precursor proteins in pollen GPI-deficient mutants could be addressed using either specific antibodies or GPI precursor protein:green fluorescent protein fusions (Sedbrook et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

SETH1andSETH2, Two Components of the Glycosylphosphatidylinositol Anchor Biosynthetic Pathway, Are Required for Pollen Germination and Tube Growth in Arabidopsis [W]

et al. 2004

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Glycosylphosphatidylinositol (GPI) anchoring provides an alternative to transmembrane domains for anchoring proteins to the cell surface in eukaryotes. GPI anchors are synthesized in the endoplasmic reticulum via the sequential addition of monosaccharides, fatty acids, and phosphoethanolamines to phosphatidylinositol. Deficiencies in GPI biosynthesis lead to embryonic lethality in animals and to conditional lethality in eukaryotic microbes by blocking cell growth, cell division, or morphogenesis. We report the genetic and phenotypic analysis of insertional mutations disrupting SETH1 and SETH2 , which encode Arabidopsis homologs of two conserved proteins involved in the first step of the GPI biosynthetic pathway. seth1 and seth2 mutations specifically block male transmission and pollen function. This results from reduced pollen germination and tube growth, which are associated with abnormal callose deposition. This finding suggests an essential role for GPI anchor biosynthesis in pollen tube wall deposition or metabolism. Using transcriptomic and proteomic approaches, we identified 47 genes that encode potential GPI-anchored proteins that are expressed in pollen and demonstrated that at least 11 of these proteins are associated with pollen membranes by GPI anchoring. Many of the identified candidate proteins are homologous with proteins involved in cell wall synthesis and remodeling or intercellular signaling and adhesion, and they likely play important roles in the establishment and maintenance of polarized pollen tube growth.

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“…Depletion of sphingolipid levels can also be achieved by addition of drugs such as myriocin, which inhibits serine palmitoyltransferase activity (24), and aureobasidin A (AbA), which blocks synthesis of the sphingolipid inositol phosphorylceramide from ceramide (25). To determine whether myriocin influences Pma1p oligomerization, we treated cells with up to 40 g/ml myriocin for 2 h. Under these conditions, we were unable to observe a significant shift of the steady-state levels of oligomeric Pma1p to monomer (data not shown), suggesting either that depletion of sphingolipid was not sufficient during the 2-h treatment or that, once formed, Pma1p oligomers are resistant to a decrease in sphingolipid levels.…”

Section: Pma1pmentioning

confidence: 99%

Ceramide Biosynthesis Is Required for the Formation of the Oligomeric H+-ATPase Pma1p in the Yeast Endoplasmic Reticulum

Lee¹,

Hamamoto

Schekman

2002

Journal of Biological Chemistry

126

154

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The yeast plasma membrane H؉ -ATPase Pma1p is one of the most abundant proteins to traverse the secretory pathway. Newly synthesized Pma1p exits the endoplasmic reticulum (ER) via COPII-coated vesicles bound for the Golgi. Unlike most secreted proteins, efficient incorporation of Pma1p into COPII vesicles requires the Sec24p homolog Lst1p, suggesting a unique role for Lst1p in ER export. Vesicles formed with mixed Sec24p-Lst1p coats are larger than those with Sec24p alone. Here, we examined the relationship between Pma1p biosynthesis and the requirement for this novel coat subunit. We show that Pma1p forms a large oligomeric complex of >1 MDa in the ER, which is packaged into COPII vesicles. Furthermore, oligomerization of Pma1p is linked to membrane lipid composition; Pma1p is rendered monomeric in cells depleted of ceramide, suggesting that association with lipid rafts may influence oligomerization. Surprisingly, monomeric Pma1p present in ceramide-deficient membranes can be exported from the ER in COPII vesicles in a reaction that is stimulated by Lst1p. We suggest that Lst1p directly conveys Pma1p into a COPII vesicle and that the larger size of mixed Sec24pLst1p COPII vesicles is not essential to the packaging of large oligomeric complexes.An essential protein of the yeast plasma membrane is the H ϩ -ATPase Pma1p. At steady state, it composes Ͼ25% of the total protein at the plasma membrane, where it generates a proton gradient that maintains the intracellular pH and drives the import of nutrients (1). Pma1p spans the lipid bilayer with 10 transmembrane segments and belongs to the family of P 2 -type ATPases, which includes the Na ϩ ,K ϩ -ATPases and Ca 2ϩ -ATPases of the mammalian plasma membrane (2, 3).As with other integral membrane proteins destined for the plasma membrane, Pma1p is translocated into the endoplasmic reticulum (ER) 1 and travels through a series of transport vesicles to its final destination (4, 5). En route, Pma1p and the glycosylphosphatidylinositol-anchored protein Gas1p become associated with lipid rafts (6, 7). Interestingly, raft association of Gas1p initiates in the ER (6), unlike in mammalian cells, where glycosylphosphatidylinositol-anchored proteins enter rafts in post-ER compartments (8, 9). Exit out of the ER is mediated by COPII (coat protein complex II) vesicles, a universal mechanism in eukaryotes employing a set of cytoplasmic coat proteins (10). Budding is regulated by the small G-protein Sar1p, which recruits two complexes, Sec23p-Sec24p and Sec13p-Sec31p (10 -12). Assembly of these three components on the surface of liposomes is sufficient to deform the lipid bilayer to generate small coated vesicles (11). On the ER membrane, Sar1p and Sec23p-Sec24p promote the capture of a number of cargo proteins, suggesting that Sec23p-Sec24p may function to selectively engage cargo proteins during coat assembly (13,14).Homologs of Sec24p have been identified in yeast and mammals (15, 16) and may act to diversify the range of cargo proteins recruited into a nascent vesicle. In yeast...

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Ceramide synthesis enhances transport of GPI-anchored proteins to the Golgi apparatus in yeast.

Cited by 211 publications

References 39 publications

Lag1p and Lac1p Are Essential for the Acyl-CoA–dependent Ceramide Synthase Reaction inSaccharomyces cerevisae

Lag1p and Lac1p Are Essential for the Acyl-CoA–dependent Ceramide Synthase Reaction inSaccharomyces cerevisae

SETH1andSETH2, Two Components of the Glycosylphosphatidylinositol Anchor Biosynthetic Pathway, Are Required for Pollen Germination and Tube Growth in Arabidopsis [W]

Ceramide Biosynthesis Is Required for the Formation of the Oligomeric H+-ATPase Pma1p in the Yeast Endoplasmic Reticulum

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