Trehalose accumulation in mutants of Saccharomyces cerevisiae deleted in the UDPG-dependent trehalose synthase-phosphatase complex
Ferreira, JC × Thevelein, Johan Hohmann, S Paschoalin, VMF Trugo, LC Panek, AD #
ELSEVIER SCIENCE BV
Biochimica et biophysica acta. General subjects vol:1335 issue:1-2 pages:40-50
date:UNIV FED RIO DE JANEIRO,DEPT BIOQUIM,INST QUIM,BR-21949900 RIO JANEIRO,BRAZIL; CATHOLIC UNIV LEUVEN,INST PLANTKUNDE,LAB MOL CELBIOL,B-3030 HEVERLEE,BELGIUM
In Saccharomyces cerrevisiae, trehalose-6-phosphate synthase converts uridine-5'-diphosphoglucose and glucose 6-phosphate to trehalose 6-phosphate which is dephosphorylated by trehalose 6-phosphatase to trehalose. These two steps take place within a complex consisting of three proteins: trehalose-6-phosphate synthase encoded by the GGS1/TPS1 (= FDP1, = BYP1, = CIF1) gene, trehalose 6-phosphatase encoded by the TPS2 gene and by a third protein encoded by both the TSL1 and TPS3 genes. Using three different methods for trehalose determination, we observed trehalose accumulation in ggs1/tps1 Delta, tps2 Delta and tsl1 Delta mutants, and in the double mutants ggs1/rps1 Delta/rps2 Delta and also in ggs1/tpsld deleted mutants suppressed for growth on glucose. All these mutants harbor MAL genes. Trehalose synthesis in these mutants is probably performed by the adenosine-5'-diphosphoglucose-dependent trehalose synthase, (ADPG-dependent trehalose synthase) which was detected in all strains tested. It is noteworthy that trehalose accumulation in these mutants was detected only in cells grown on weakly repressive carbon sources such as maltose and galactose or during the transition phase from fermentable to non-fermentable growth on glucose. alpha-Glucosidase activity was always present in high amounts. We also describe an adenosine-diphosphoglucosepyrophosphorylase (ADPG-pyrophosphorylase) activity in Saccharomyces cerevisiae which increased concomitantly with the accumulation of trehalose during the transition phase from fermentable to non-fermentable growth in MAL-constitutive (MAL2-8(c)) strains. The same was observed when MAL-induced (MAL1) strains were compared during growth on glucose and maltose. These results led us to conclude that maltose-induced trehalose accumulation is independent of the UDPG-dependent trehalose-6-phosphate synthase/phosphatase complex; that the ADPG-dependent trehalose synthase is responsible for maltose-induced trehalose accumulation probably by forming a complex with a specific trehalose-6-phosphatase activity and that ADPG synthesis is activated during trehalose accumulation under these conditions.