A yeast homologue of the bovine lens fibre MIP gene family complements the growth defect of a Saccharomyces cerevisiae mutant on fermentable sugars but not its defect in glucose-induced RAS-mediated cAMP signalling.

Abstract

Recently a new family of membrane proteins comprising the bovine lens fibre major intrinsic protein, soybean nodulin‐26 protein and the Escherichia coli glycerol facilitator has been described [M.E. Baker and M.H. Saier, Jr (1990) Cell, 60, 185–186]. These proteins have six putative membrane spanning domains and one (probably intracellular) intermembrane fragment is particularly well conserved. We have identified a new member of this family in the yeast Saccharomyces cerevisiae. It also possesses the six transmembrane domains and the highly conserved intermembrane sequence. In contrast to the other three proteins which are all approximately 280 amino acids long, the yeast protein has an N‐terminal extension of approximately 250 amino acids, which contains a string of 17 asparagine residues and a C‐terminal extension of approximately 150 amino acids. The gene, which we called FPS1 (for fdp1 suppressor), suppresses in single copy the growth defect on fermentable sugars of the yeast fdp1 mutant but it is not allelic to FDP1. The deficiency of the fdp1 mutant in glucose‐induced RAS‐mediated cAMP signalling and in rapid glucose‐induced changes in the activity of certain enzymes was not restored. Deletion of FPS1 does not cause any of the phenotypic deficiencies of the fdp1 mutant.

Arsenite transport by mammalian aquaglyceroporins AQP7 and AQP9

“…Although the glpF mutant did not exhibit increased arsenite tolerance, we postulated that GlpF also transports As(OH) 3 , the primary ionization state of arsenite in neutral solutions, but that redundancy in arsenic transporters dampens the effect of the glpF mutation (13). Recently the GlpF homolog Fps1p, a S. cerevisiae aquaglyceroporin (17), was clearly shown to be involved in uptake of arsenite (18). Deletion of the FPS1 gene resulted in increased tolerance to both arsenite and antimonite, and fps1⌬ cells exhibited decreased uptake of radioactive arsenite.…”

New insights on glycerol transport in Saccharomyces cerevisiae

“…Glycerol, the main compatible solute used by yeasts under low a w in high osmolarity environments [1], can permeate Saccharomyces cerevisiae plasma membrane through a constitutively expressed channel, Fps1p [2][3][4], and a H þ /symport, active in cells derepressed by growth on non-fermentable carbon sources [5]. This transport system was associated with the expression of the genes GUP1 and GUP2 [6].…”

Structural analysis of the subunits of the trehalose‐6‐phosphate synthase/phosphatase complex in Saccharomyces cerevisiae and their function during heat shock

“…Several mutations described earlier as fdp1, cif1, byp1, and glc6 have been shown to be alleles of the same gene and to exert a wide range of pleiotropic phenotypes (reviewed in Thevelein and Hohmann, 1995). An important phenotype of all these mutants (except glc6), however, is that they are unable to grow on glucose, apparently because of an uncontrolled influx of glucose into the glycolytic pathway (Van Aelst et al, 1991;Hohmann et al, 1993;Blá zquez et al, 1993;Blá zquez and Gancedo, 1994). At least three different models for this unexpected role of Tps1 (also called Ggs1 in this context) in the control of glycolysis have been presented, as follows.…”