Heterologous expression of mammalian Na/H antiporters in Saccharomyces cerevisiae

Saccharomyces cerivisiae as a model system for kidney disease: what can yeast tell us about renal function?

“…When NHE2 and NHE3 were expressed from a strong promoter, the salt tolerance of yeast lacking endogenous sodium transporters increased slightly, despite the fact that most of the transporters remained in the ER (32,33). However, a decrease in the amount of the E3 ubiquitin ligase, Rsp5, increased the number of channels at the plasma membrane (32).…”

“…When NHE2 and NHE3 were expressed from a strong promoter, the salt tolerance of yeast lacking endogenous sodium transporters increased slightly, despite the fact that most of the transporters remained in the ER (32,33). However, a decrease in the amount of the E3 ubiquitin ligase, Rsp5, increased the number of channels at the plasma membrane (32). Rsp5 is the yeast homolog of the mammalian ubiquitin ligase, Nedd4 -2, which is required for the endocytosis and lysosomal degradation of ENaC (59,138,149) and possibly CFTR (20) after retrieval of the plasma membrane; therefore, these data suggest that later steps during the secretion, recycling, and quality control of renal proteins can be characterized in yeast.…”

The expression in Saccharomyces cerevisiae of a glucose/xylose symporter from Candida intermedia is affected by the presence of a glucose/xylose facilitator

“…Based on available knowledge, it is not possible to outline general methods to improve functionality of heterologous membrane proteins in S. cerevisiae, since different proteins seem to require specific and distinct conditions to be correctly targeted to the plasma membrane and/or display their full activity (Wieczorke et al, 2003;Flegelova et al, 2006). This is illustrated by our observations of the deleterious effect on Gxs1p expression of a mutation selected for improving functional expression of the mammalian GLUT1 transporter in S. cerevisiae (results not shown).…”

“…Protein levels of C. intermedia transporters in S. cerevisiae It has been often observed that plasma membrane proteins expressed in an heterologous context may be deficiently targeted or present serious problems for the secretion pathway of the host cell, in particular when overexpressed (Wieczorke et al, 2003;Flegelova et al, 2006). To examine this question, we constructed a Gxs1-GFP fusion for use as a reporter for the subcellular localization of heterologously expressed Gxs1p.…”

Alkali Metal Cation Transport and Homeostasis in Yeasts

“…This phenotype complementation approach has been successfully used to characterize the localization and function of mammalian and (mainly) plant plasma membrane antiporters (76,226) as well as the intracellular homologs of ScNhx1 (81,90,121,225) and ScKha1 (152). However, much more research is needed to fully understand the role of alkali metal cation/H ϩ antiporters in multicellular organisms because of the gene redundancy (e.g., 9 NHE isoforms in mammalian cells [202] or 40 genes encoding putative Na ϩ /H ϩ antiporters in A. thaliana [161]) and the different expression levels and various functions according to tissue, organ, and phase of development (see, e.g., references 202 and 302).…”