Boosting endoplasmic reticulum folding capacity reduces unfolded protein response activation and intracellular accumulation of human kidney anion exchanger 1 in Saccharomyces cerevisiae
Open Access
- 25 May 2021
- Vol. 38 (9), 521-534
- https://doi.org/10.1002/yea.3652
Abstract
Human kidney anion exchanger 1 (kAE1) facilitates simultaneous efflux of bicarbonate and absorption of chloride at the basolateral membrane of α-intercalated cells. In these cells, kAE1 contributes to systemic acid–base balance along with the proton pump v-H+-ATPase and the cytosolic carbonic anhydrase II. Recent electron microscopy analyses in yeast demonstrate that heterologous expression of several kAE1 variants causes a massive accumulation of the anion transporter in intracellular membrane structures. Here, we examined the origin of these kAE1 aggregations in more detail. Using various biochemical techniques and advanced light and electron microscopy, we showed that accumulation of kAE1 mainly occurs in endoplasmic reticulum (ER) membranes which eventually leads to strong unfolded protein response (UPR) activation and severe growth defect in kAE1 expressing yeast cells. Furthermore, our data indicate that UPR activation is dose dependent and uncoupled from the bicarbonate transport activity. By using truncated kAE1 variants, we identified the C-terminal region of kAE1 as crucial factor for the increased ER stress level. Finally, a redistribution of ER-localized kAE1 to the cell periphery was achieved by boosting the ER folding capacity. Our findings not only demonstrate a promising strategy for preventing intracellular kAE1 accumulation and improving kAE1 plasma membrane targeting but also highlight the versatility of yeast as model to investigate kAE1-related research questions including the analysis of structural features, protein degradation and trafficking. Furthermore, our approach might be a promising strategy for future analyses to further optimize the cell surface targeting of other disease-related PM proteins, not only in yeast but also in mammalian cells.Keywords
Funding Information
- Deutsche Forschungsgemeinschaft (IRTG 1830)
This publication has 57 references indexed in Scilit:
- A new class of carriers that transport selective cargo from the trans Golgi network to the cell surfaceThe EMBO Journal, 2012
- Fiji: an open-source platform for biological-image analysisNature Methods, 2012
- Metabolic engineering of recombinant protein secretion by Saccharomyces cerevisiaeFEMS Yeast Research, 2012
- Kar2p availability defines distinct forms of endoplasmic reticulum stress in living cellsMolecular Biology of the Cell, 2012
- Fast-acting and nearly gratuitous induction of gene expression and protein depletion inSaccharomyces cerevisiaeMolecular Biology of the Cell, 2011
- Unfolded Proteins Are Ire1-Activating Ligands That Directly Induce the Unfolded Protein ResponseScience, 2011
- Saccharomyces cerivisiae as a model system for kidney disease: what can yeast tell us about renal function?American Journal of Physiology-Renal Physiology, 2011
- Glyceraldehyde 3-phosphate dehydrogenase is required for band 3 (anion exchanger 1) membrane residency in the mammalian kidneyAmerican Journal of Physiology-Renal Physiology, 2011
- Membrane potential governs lateral segregation of plasma membrane proteins and lipids in yeastThe EMBO Journal, 2006
- Exomer: a coat complex for transport of select membrane proteins from the trans-Golgi network to the plasma membrane in yeastThe Journal of cell biology, 2006