Analysis of PFK3—A gene involved in particulate phosphofructokinase synthesis reveals additional functions of TPS2 in Saccharomyces cerevisiae

Abstract

The pfk3 mutation of Saccharomyces cerevisiae causes glucose-negativity in a pfk1 genetic background, the mutant is temperature-sensitive for growth and homozygous diploids do not sporulate. It fails to accumulate trehalose, and has an altered glycogen accumulation profile under glucose-starvation conditions. pfk3-6, one of the alleles of pfk3, has an altered morphology, forming long chain-like structures at 36 degrees C. The PFK3 gene was cloned by complementation of the mutant phenotypes. Integrative transformation demonstrated that the complementing fragment encoded the authentic PFK3 gene. The disruption of the gene does not affect viability. Like the EMS-induced pfk3 mutant, the disruptants are temperature-sensitive and in a pfk1 genetic background are also glucose-negative. The PFK3 transcript is induced by heat-shock. Partial DNA sequence shows that PFK3 is identical to TPS2 (De Virgilio et al., 1993). We demonstrate that, apart from being a structural determinant of trehalose 6-phosphate phosphatase, PFK3 (TPS2) is required for PFKII synthesis and normal regulation of S. cerevisiae response to nutrient and thermal stresses.

Weak organic acid treatment causes a trehalose accumulation in low-pH cultures ofSaccharomyces cerevisiae, not displayed by the more preservative-resistantZygosaccharomyces bailii

“…We have observed that this mutant, whose basal trehalose is only slightly higher than normal during pH 6.6 25°C growth, maintains 2.5‐fold higher trehalose during growth at 30°C and 6‐fold higher trehalose at 37°C. Higher trehalose levels during normal growth of pfk1 mutant cells have also been noted by Sur et al [19] and are consistent with the elevated glucose‐6‐phosphate and fructose‐6‐phosphate levels reported by Heinisch [18].…”

“…Since PFK1 contributes most of the PFK activity in glucose‐grown log phase S . cerevisiae cells [18, 19], we investigated whether the pfk1 S . cerevisiae mutant would display enhanced trehalose induction with 25°C weak organic acid treatment at pH 4.5.…”

Reserve carbohydrates metabolism in the yeast Saccharomyces cerevisiae

“…This latter phenotype has not been elucidated yet and it contrasts with the fact that a null mutation of GLC6 hyperaccumulates glycogen due to very high levels of Glc6P and due to the presence of a more active form of glycogen synthase ( [89], unpublished data). This gene was also isolated in a screen for mutants unable to acquire heat shock resistance in stationary phase [92], mutants able to neutralize the pleiotropic drug resistance phenotype caused by overexpression of YAP1 [93], and by complementation of a thermosensitive glucose-negative mutant harboring very low 6phosphofructo-1-kinase activity [94]. Peptide sequencing of the 100-kDa band of the puri¢ed trehalose synthase complex was used to clone TPS2 which encodes the Tre6P phosphatase catalytic subunit [90].…”

Mutant analysis reveals complex regulation of sphingolipid long chain base phosphates and long chain bases during heat stress in yeast

“…However, we cannot eliminate the possibility that they play a role that is redundant with some other molecule. Heat is known to induce transcription of many genes including TPS2, which encodes trehalose-6-phosphate phosphatase, an enzyme required for trehalose synthesis (De Virgilio et al, 1993;Gounalaki and Thireos, 1994;Sur et al, 1994). We previously showed that transcription of TPS2 could be induced also by treating cells with DHS (Dickson et al, 1997).…”