Glucose-induced internalization of the S. cerevisiae galactose permease Gal2 is dependent on phosphorylation and ubiquitination of its aminoterminal cytoplasmic tail

ABSTRACT The hexose permease Gal2 of Saccharomyces cerevisiae is expressed only in the presence of its physiological substrate galactose. Glucose tightly represses the GAL2 gene and also induces the clearance of the transporter from the plasma membrane by ubiquitination and subsequent degradation in...

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Bibliographic Details
Published in:FEMS yeast research 2021-05, Vol.21 (3), p.1
Main Authors: Tamayo Rojas, Sebastian A, Schmidl, Sina, Boles, Eckhard, Oreb, Mislav
Format: Article
Language:English
Subjects:
Adaptor proteins
Arrestin
Biodegradation
Carbenicillin
Dextrose
Galactose
Glucose
Hexose
Hydrolysates
Internalization
Ligases
Pectin
Permease
Phosphorylation
Physiological aspects
Saccharomyces cerevisiae
Ubiquitin
Ubiquitin-protein ligase
Ubiquitination
Yeast
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Summary:ABSTRACT The hexose permease Gal2 of Saccharomyces cerevisiae is expressed only in the presence of its physiological substrate galactose. Glucose tightly represses the GAL2 gene and also induces the clearance of the transporter from the plasma membrane by ubiquitination and subsequent degradation in the vacuole. Although many factors involved in this process, especially those responsible for the upstream signaling, have been elucidated, the mechanisms by which Gal2 is specifically targeted by the ubiquitination machinery have remained elusive. Here, we show that ubiquitination occurs within the N-terminal cytoplasmic tail and that the arrestin-like proteins Bul1 and Rod1 are likely acting as adaptors for docking of the ubiquitin E3-ligase Rsp5. We further demonstrate that phosphorylation on multiple residues within the tail is indispensable for the internalization and possibly represents a primary signal that might trigger the recruitment of arrestins to the transporter. In addition to these new fundamental insights, we describe Gal2 mutants with improved stability in the presence of glucose, which should prove valuable for engineering yeast strains utilizing complex carbohydrate mixtures present in hydrolysates of lignocellulosic or pectin-rich biomass. Phosphorylation and ubiquitination are required for the glucose-induced internalization and degradation of the galactose permease Gal2.
ISSN:1567-1356
1567-1364
DOI:10.1093/femsyr/foab019