When Saccharomyces cerevisiae cells growing on galactose are transferred onto glucose medium containing cycloheximide, an inhibitor of protein synthesis, a rapid reduction of Gal2p-mediated galactose uptake is observed. We show that glucose-induced inactivation of Gal2p is due to its degradation. Stabilization of Gal2p in pra1 mutant cells devoid of vacuolar proteinase activity is observed. Subcellular fractionation and indirect immunofluorescence showed that the Gal2 transporter accumulates in the vacuole of the mutant cells, directly demonstrating that its degradation requires vacuolar proteolysis. In contrast, Gal2p degradation is proteasome independent since its half-life is unaffected in pre1-1 pre2-2, cim3-1, and cim5-1 mutants defective in several subunits of the protease complex. In addition, vacuolar delivery of Gal2p was shown to be blocked in conditional end3 and end4 mutants at the nonpermissive temperature, indicating that delivery of Gal2p to the vacuole occurs via the endocytic pathway. Taken together, the results presented here demonstrate that glucose-induced proteolysis of Gal2p is dependent on endocytosis and vacuolar proteolysis and is independent of the functional proteasome. Moreover, we show that Gal2p is ubiquitinated under conditions of glucose-induced inactivation.

Institute of Physiology Department of Membrane Transport Academy of Sciences of the Czech Republic Prague

Zobrazit více v PubMed

Biochem Biophys Res Commun. 1994 Apr 15;200(1):45-51 PubMed

Mol Biol Cell. 1993 May;4(5):511-21 PubMed

EMBO J. 1991 Mar;10(3):555-62 PubMed

J Biol Chem. 1994 Apr 1;269(13):9833-41 PubMed

Nature. 1995 Jan 5;373(6509):78-81 PubMed

Science. 1994 Sep 2;265(5177):1454-8 PubMed

Curr Opin Cell Biol. 1993 Dec;5(6):990-6 PubMed

Cell. 1994 Oct 21;79(2):233-44 PubMed

Methods Enzymol. 1991;194:565-602 PubMed

FEBS Lett. 1993 Oct 25;333(1-2):165-8 PubMed

EMBO J. 1994 Jul 15;13(14):3261-71 PubMed

EMBO J. 1994 Dec 15;13(24):6021-30 PubMed

Biochem Biophys Res Commun. 1994 Jun 15;201(2):769-75 PubMed

J Bacteriol. 1995 Oct;177(19):5622-7 PubMed

FEBS Lett. 1996 Jan 8;378(2):177-81 PubMed

FEBS Lett. 1986 Oct 27;207(2):258-61 PubMed

Gene. 1981 Oct;15(1):81-93 PubMed

J Biol Chem. 1989 Sep 25;264(27):16037-45 PubMed

EMBO J. 1996 May 1;15(9):2069-76 PubMed

Mol Biol Cell. 1994 Nov;5(11):1185-98 PubMed

Nature. 1993 Nov 25;366(6453):358-62 PubMed

EMBO J. 1995 Jan 16;14(2):303-12 PubMed

J Biol Chem. 1995 Feb 10;270(6):2423-6 PubMed

J Biol Chem. 1992 Apr 25;267(12):8021-9 PubMed

J Biol Chem. 1991 Nov 5;266(31):21150-7 PubMed

Gene. 1989 Dec 28;85(2):313-9 PubMed

Trends Cell Biol. 1993 Aug;3(8):273-7 PubMed

Curr Opin Cell Biol. 1995 Apr;7(2):215-23 PubMed

J Bacteriol. 1986 Apr;166(1):313-8 PubMed

J Biol Chem. 1991 May 5;266(13):7963-6 PubMed

J Bacteriol. 1989 Aug;171(8):4486-93 PubMed

Trends Biochem Sci. 1996 Mar;21(3):96-102 PubMed

Mol Cell Biol. 1991 Feb;11(2):1114-24 PubMed

J Bacteriol. 1996 Apr;178(8):2245-54 PubMed

J Cell Biol. 1993 Jul;122(1):53-65 PubMed

J Biol Chem. 1995 Nov 3;270(44):26446-50 PubMed

Mol Cell Biol. 1995 Feb;15(2):731-41 PubMed

J Bacteriol. 1993 Dec;175(23):7689-96 PubMed

Nature. 1991 Mar 28;350(6316):313-8 PubMed

J Biol Chem. 1996 Apr 26;271(17):9934-41 PubMed

J Gen Microbiol. 1986 Feb;132(2):379-85 PubMed

Mol Cell Biol. 1995 Nov;15(11):5879-87 PubMed

J Biol Chem. 1995 Sep 1;270(35):20742-7 PubMed

Cell. 1994 Jul 1;77(7):1037-50 PubMed

Cell. 1996 Jan 26;84(2):277-87 PubMed

J Bacteriol. 1989 Jun;171(6):3539-44 PubMed

J Bacteriol. 1991 Mar;173(5):1817-20 PubMed

FEBS Lett. 1994 Oct 31;354(1):50-2 PubMed

FEBS Lett. 1994 Aug 1;349(2):270-4 PubMed

J Cell Biol. 1993 Jan;120(1):55-65 PubMed

Mol Biol Rep. 1995;21(1):3-10 PubMed

J Biol Chem. 1994 Jan 21;269(3):2245-51 PubMed

J Biol Chem. 1977 Sep 25;252(18):6399-402 PubMed

Science. 1996 Sep 20;273(5282):1725-8 PubMed

J Biol Chem. 1995 Feb 10;270(6):2525-34 PubMed

Crit Rev Biochem Mol Biol. 1993;28(4):259-308 PubMed

J Biol Chem. 1993 Mar 5;268(7):5115-20 PubMed

Multilevel regulation of an α-arrestin by glucose depletion controls hexose transporter endocytosis

Regulations of sugar transporters: insights from yeast

Immunity to killer toxin K1 is connected with the Golgi-to-vacuole protein degradation pathway

Glucose-induced monoubiquitination of the Saccharomyces cerevisiae galactose transporter is sufficient to signal its internalization