Nutrient sensing and transceptor-mediated metabolic control in yeast

Area of Science:

• * Molecular biology and cell signaling in eukaryotic microorganisms.
• * Focus on yeast (Saccharomyces cerevisiae) as a model organism for nutrient sensing.
• * Exploration of plasma membrane transport and signal transduction.

Background:

• * Yeast utilizes classical pathways like cAMP-protein kinase A (PKA), Snf1/AMP-activated protein kinase, target of rapamycin complex 1 (TORC1)-Sch9, and amino acid control to sense nutrients.
• * Established pathways link nutrient levels (carbon, nitrogen, phosphate, amino acids) to cellular growth, metabolism, and stress adaptation.
• * Emerging evidence suggests plasma membrane nutrient transporters have signaling roles beyond substrate uptake.

Purpose of the Study:

• * To review the role of yeast nutrient transceptors in sensing extracellular nutrients.
• * To highlight how these dual-function proteins link nutrient availability to intracellular regulatory responses.
• * To discuss mechanistic insights into transceptor function, including transport-signaling uncoupling.

Main Methods:

• * Literature review of studies on yeast nutrient sensing pathways.
• * Focus on specific nutrient transceptors: Gap1, Mep2, Pho84, Sul1/Sul2, Can1, Ftr1, and Zrt1.
• * Analysis of mechanistic insights into transceptor signaling, including kinase associations.

Main Results:

• * Nutrient transceptors act as dual-function proteins, mediating both transport and signaling.
• * These proteins activate intracellular responses like trehalose mobilization, stress resistance, and growth resumption.
• * Transceptors can influence TORC1-Sch9 signaling and activate PKA pathways without altering cAMP levels.

Conclusions:

• * Nutrient transceptors represent a crucial layer of nutrient sensing in yeast.
• * They translate extracellular nutrient cues into specific cellular responses.
• * Understanding transceptors provides deeper insights into yeast's adaptive mechanisms.