Internalization of heterologous sugar transporters by endogenous α-arrestins in the yeast Saccharomyces cerevisiae
- Author(s): Sen, A
- Acosta-Sampson, L
- Alvaro, CG
- Ahn, JS
- Cate, JHD
- Thorner, J
- et al.
Published Web Locationhttps://doi.org/10.1128/AEM.02148-16
© 2016, American Society for Microbiology. All Rights Reserved. When expressed in Saccharomyces cerevisiae using either of two constitutive yeast promoters (PGK1promand CCW12prom), the transporters CDT-1 and CDT-2 from the filamentous fungus Neurospora crassa are able to catalyze, respectively, active transport and facilitated diffusion of cellobiose (and, for CDT-2, also xylan and its derivatives). In S. cerevisiae, endogenous permeases are removed from the plasma membrane by clathrin-mediated endocytosis and are marked for internalization through ubiquitinylation catalyzed by Rsp5, a HECT class ubiquitin:protein ligase (E3). Recruitment of Rsp5 to specific targets is mediated by a 14-member family of endocytic adaptor proteins, termed α-arrestins. Here we demonstrate that CDT-1 and CDT-2 are subject to α-arrestin-mediated endocytosis, that four α-arrestins (Rod1, Rog3, Aly1, and Aly2) are primarily responsible for this internalization, that the presence of the transport substrate promotes transporter endocytosis, and that, at least for CDT-2, residues located in its C-terminal cytosolic domain are necessary for its efficient endocytosis. Both α-arrestin-deficient cells expressing CDT-2 and otherwise wild-type cells expressing CDT-2 mutants unresponsive to α-arrestin-driven internalization exhibit an increased level of plasma membrane-localized transporter compared to that of wild-type cells, and they grow, utilize the transport substrate, and generate ethanol anaerobically better than control cells.
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