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Surveying the floodgates: estimating protein flux into the endoplasmic reticulum lumen in Saccharomyces cerevisiae.

Vincent M, Whidden M, Schnell S - Front Physiol (2014)

Bottom Line: While the involvement of various molecules associated with the Sec61 complex has been thoroughly characterized, little attention has been given to the overall flux through these channels.We estimate an average of 460 proteins enter the endoplasmic reticulum every second, with an absolute minimum and maximum flux of 78 and 3700 molecules per second, respectively.With current technologies limiting the ability to obtain accurate measurements of these events, our estimates shed light on the flow of protein entering the endoplasmic reticulum lumen.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School Ann Arbor, MI, USA ; Department of Molecular, Cellular, and Developmental Biology, University of Michigan Ann Arbor, MI, USA.

ABSTRACT
Endoplasmic reticulum resident proteins, along with all proteins traveling through the secretory pathway must enter endoplasmic reticulum lumen through membrane-embedded translocons. In Saccharomyces cerevisiae the heterotrimeric endoplasmic reticulum translocon is composed of the Sec61p, Sss1p, and Sbh1p core subunits. While the involvement of various molecules associated with the Sec61 complex has been thoroughly characterized, little attention has been given to the overall flux through these channels. In this work we carried out a meta-analysis to estimate the average and absolute flux of proteins into the endoplasmic reticulum lumen. We estimate an average of 460 proteins enter the endoplasmic reticulum every second, with an absolute minimum and maximum flux of 78 and 3700 molecules per second, respectively. With current technologies limiting the ability to obtain accurate measurements of these events, our estimates shed light on the flow of protein entering the endoplasmic reticulum lumen.

No MeSH data available.


Distribution of the ER-targeted protein population. Cellular abundance and subcellular localization data has been obtained from Ghaemmaghami et al. (2003) and Huh et al. (2003), respectively. Primary sequence lengths for all proteins were obtained from the Saccharomyces Genome Database (http://www.yeastgenome.org), accessed June 5, 2014.
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Figure 1: Distribution of the ER-targeted protein population. Cellular abundance and subcellular localization data has been obtained from Ghaemmaghami et al. (2003) and Huh et al. (2003), respectively. Primary sequence lengths for all proteins were obtained from the Saccharomyces Genome Database (http://www.yeastgenome.org), accessed June 5, 2014.

Mentions: We obtained the primary sequence length for each of the 226 ER-targeted proteins quantified by Ghaemmaghami et al. (2003) (Figure 1). Next, the average length of an ER-localized protein was determined by weighting the length of each by its corresponding abundance (number of molecules per cell of a specific protein divided by total number of ER-localized molecules per cell):(1)L=∑i = 1226(AXi·LXi)AER


Surveying the floodgates: estimating protein flux into the endoplasmic reticulum lumen in Saccharomyces cerevisiae.

Vincent M, Whidden M, Schnell S - Front Physiol (2014)

Distribution of the ER-targeted protein population. Cellular abundance and subcellular localization data has been obtained from Ghaemmaghami et al. (2003) and Huh et al. (2003), respectively. Primary sequence lengths for all proteins were obtained from the Saccharomyces Genome Database (http://www.yeastgenome.org), accessed June 5, 2014.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230051&req=5

Figure 1: Distribution of the ER-targeted protein population. Cellular abundance and subcellular localization data has been obtained from Ghaemmaghami et al. (2003) and Huh et al. (2003), respectively. Primary sequence lengths for all proteins were obtained from the Saccharomyces Genome Database (http://www.yeastgenome.org), accessed June 5, 2014.
Mentions: We obtained the primary sequence length for each of the 226 ER-targeted proteins quantified by Ghaemmaghami et al. (2003) (Figure 1). Next, the average length of an ER-localized protein was determined by weighting the length of each by its corresponding abundance (number of molecules per cell of a specific protein divided by total number of ER-localized molecules per cell):(1)L=∑i = 1226(AXi·LXi)AER

Bottom Line: While the involvement of various molecules associated with the Sec61 complex has been thoroughly characterized, little attention has been given to the overall flux through these channels.We estimate an average of 460 proteins enter the endoplasmic reticulum every second, with an absolute minimum and maximum flux of 78 and 3700 molecules per second, respectively.With current technologies limiting the ability to obtain accurate measurements of these events, our estimates shed light on the flow of protein entering the endoplasmic reticulum lumen.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Integrative Physiology, University of Michigan Medical School Ann Arbor, MI, USA ; Department of Molecular, Cellular, and Developmental Biology, University of Michigan Ann Arbor, MI, USA.

ABSTRACT
Endoplasmic reticulum resident proteins, along with all proteins traveling through the secretory pathway must enter endoplasmic reticulum lumen through membrane-embedded translocons. In Saccharomyces cerevisiae the heterotrimeric endoplasmic reticulum translocon is composed of the Sec61p, Sss1p, and Sbh1p core subunits. While the involvement of various molecules associated with the Sec61 complex has been thoroughly characterized, little attention has been given to the overall flux through these channels. In this work we carried out a meta-analysis to estimate the average and absolute flux of proteins into the endoplasmic reticulum lumen. We estimate an average of 460 proteins enter the endoplasmic reticulum every second, with an absolute minimum and maximum flux of 78 and 3700 molecules per second, respectively. With current technologies limiting the ability to obtain accurate measurements of these events, our estimates shed light on the flow of protein entering the endoplasmic reticulum lumen.

No MeSH data available.