Specialized membrane-localized chaperones prevent aggregation of polytopic proteins in the ER

Kota, Jhansi; Ljungdahl, Per O.

doi:10.1083/jcb.200408106

Cited by 93 publications

(122 citation statements)

References 47 publications

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“…It was proposed that this mechanism provided a means to facilitate early folding events before release into the lipid bilayer. It has been speculated that the endoplasmic reticulum-localized TRAM protein has a similar function as YidC, and it has also been shown that there are specialized chaperones in the endoplasmic reticulum mediating the co-translational folding of specific membrane proteins (57)(58)(59).…”

Section: Discussionmentioning

confidence: 99%

Biogenesis of MalF and the MalFGK2 Maltose Transport Complex in Escherichia coli Requires YidC

Wagner

Pop

Haan

et al. 2008

Journal of Biological Chemistry

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The polytopic inner membrane protein MalF is a constituent of the MalFGK 2 maltose transport complex in Escherichia coli. We have studied the biogenesis of MalF using a combination of in vivo and in vitro approaches. MalF is targeted via the SRP pathway to the Sec/YidC insertion site. Despite close proximity of nascent MalF to YidC during insertion, YidC is not required for the insertion of MalF into the membrane. However, YidC is required for the stability of MalF and the formation of the MalFGK 2 maltose transport complex. Our data indicate that YidC supports the folding of MalF into a stable conformation before it is incorporated into the maltose transport complex.

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Section: Discussionmentioning

confidence: 99%

Biogenesis of MalF and the MalFGK2 Maltose Transport Complex in Escherichia coli Requires YidC

Wagner

Pop

Haan

et al. 2008

Journal of Biological Chemistry

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“…Synthetic minimal media containing allantoin (SAD) as the sole nitrogen source have been described (Kota and Ljungdahl 2005). Low-phosphate media were prepared according to O'Connell and Baker (1992).…”

Section: Methodsmentioning

confidence: 99%

“…AAPs depend on the membrane chaperone Shr3 to exit ER (Ljungdahl et al 1992). In the absence of Shr3, AAPs aggregate in the ER and form large molecular weight complexes that are excluded from COPII transport vesicles (Kuehn et al 1996;Gilstring et al 1999;Kota and Ljungdahl 2005). Due to the severely compromised ability of AAPs to exit the ER, shr3 null mutant cells possess low levels of AAP at the plasma membrane and consequently are unable to effectively take up amino acids.…”

mentioning

confidence: 99%

Ssh4, Rcr2 and Rcr1 Affect Plasma Membrane Transporter Activity in Saccharomyces cerevisiae

Kota

Melin-Larsson²,

Ljungdahl

et al. 2007

Genetics

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Nutrient uptake in the yeast Saccharomyces cerevisiae is a highly regulated process. Cells adjust levels of nutrient transporters within the plasma membrane at multiple stages of the secretory and endosomal pathways. In the absence of the ER-membrane-localized chaperone Shr3, amino acid permeases (AAP) inefficiently fold and are largely retained in the ER. Consequently, shr3 null mutants exhibit greatly reduced rates of amino acid uptake due to lower levels of AAPs in their plasma membranes. To further our understanding of mechanisms affecting AAP localization, we identified SSH4 and RCR2 as high-copy suppressors of shr3 null mutations. The overexpression of SSH4, RCR2, or the RCR2 homolog RCR1 increases steady-state AAP levels, whereas the genetic inactivation of these genes reduces steady-state AAP levels. Additionally, the overexpression of any of these suppressor genes exerts a positive effect on phosphate and uracil uptake systems. Ssh4 and Rcr2 primarily localize to structures associated with the vacuole; however, Rcr2 also localizes to endosome-like vesicles. Our findings are consistent with a model in which Ssh4, Rcr2, and presumably Rcr1, function within the endosome-vacuole trafficking pathway, where they affect events that determine whether plasma membrane proteins are degraded or routed to the plasma membrane.

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“…AAPs are cotranslationally inserted into the ER membrane, which is contiguous with the outer nuclear membrane. Movement of AAPs to the PM (represented by the dashed arrow, right panel) requires the ER membrane-localized chaperone Shr3 (Ljungdahl et al 1992;Kota and Ljungdahl 2005;Kota et al 2007). (B) Transporterbased model for Ssy1 amino acid receptor function .…”

Section: Pathway Genesmentioning

confidence: 99%

Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

2012

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Ever since the beginning of biochemical analysis, yeast has been a pioneering model for studying the regulation of eukaryotic metabolism. During the last three decades, the combination of powerful yeast genetics and genome-wide approaches has led to a more integrated view of metabolic regulation. Multiple layers of regulation, from suprapathway control to individual gene responses, have been discovered. Constitutive and dedicated systems that are critical in sensing of the intra- and extracellular environment have been identified, and there is a growing awareness of their involvement in the highly regulated intracellular compartmentalization of proteins and metabolites. This review focuses on recent developments in the field of amino acid, nucleotide, and phosphate metabolism and provides illustrative examples of how yeast cells combine a variety of mechanisms to achieve coordinated regulation of multiple metabolic pathways. Importantly, common schemes have emerged, which reveal mechanisms conserved among various pathways, such as those involved in metabolite sensing and transcriptional regulation by noncoding RNAs or by metabolic intermediates. Thanks to the remarkable sophistication offered by the yeast experimental system, a picture of the intimate connections between the metabolomic and the transcriptome is becoming clear.

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Specialized membrane-localized chaperones prevent aggregation of polytopic proteins in the ER

Cited by 93 publications

References 47 publications

Biogenesis of MalF and the MalFGK2 Maltose Transport Complex in Escherichia coli Requires YidC

Biogenesis of MalF and the MalFGK2 Maltose Transport Complex in Escherichia coli Requires YidC

Ssh4, Rcr2 and Rcr1 Affect Plasma Membrane Transporter Activity in Saccharomyces cerevisiae

Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

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