Sensors of extracellular nutrients in Saccharomyces cerevisiae.
It has been known for a long time that yeast are capable of making rapid metabolic adjustments in response to changing extracellular nutrient conditions. Until recently it was thought that yeast, in contrast to mammalian cells, primarily monitored nutrient availability through the activity of intracellular sensors. Recent advances in our understanding of nutrient sensing indicate that yeast cells possess several nutrient-sensing systems localized in the plasma membrane that transduce information regarding the presence of extracellular amino acids, ammonium. and glucose. Strikingly, the transmembrane components of several of these sensors, Ssylp, Mep2p, Snf3p. and Rgt2p, are unique members of nutrient-transport protein families. Perhaps with the exception of Mep2p, the ability of these transporter homologues to transduce nutrient-(ligand)-induced signals across the plasma membrane appears to be independent of nutrient uptake; and thus these sensor components may function analogously to traditional ligand-dependent receptors. Additionally, the G protein-coupled receptor Gpr1p has been shown to exhibit properties consistent with it being a sensor. These recent advances indicate that yeast cells obtain information regarding their growth environments using sensing systems that are more similar to those present in mammalian cells than previously thought. The fact that yeast plasma membrane nutrient sensors have only recently been discovered reveals how little is understood regarding the molecular signals that enable eukaryotic cells to adapt to changing environments.
Forsberg
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Ludwig Institute for Cancer Research, Stockholm, Sweden.
Ljungdahl
P O
PO
D000596:Amino Acids / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D002352:Carrier Proteins / Q000502:physiology*; D027682:Cation Transport Proteins; D002455:Cell Division / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000502:physiology*; D009004:Monosaccharide Transport Proteins / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
D000596:Amino Acids; D002352:Carrier Proteins; D027682:Cation Transport Proteins; C109334:GPR1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; C107270:MEP2 protein, S cerevisiae; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; C106976:PTR3 protein, S cerevisiae; C112512:RGT2 protein, S cerevisiae; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C104463:SNF3 protein, S cerevisiae; C120527:SSY1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D002244:Carbon; D005947:Glucose; D009584:Nitrogen