Journal: The Journal of Biological Chemistry
Article Title: TOR signaling regulates GPCR levels on the plasma membrane and suppresses the Saccharomyces cerevisiae mating pathway
doi: 10.1016/j.jbc.2025.110700
Figure Lengend Snippet: TORC1 inhibition leads to CME of Ste2 through α-arrestins and Ypk1. A , to identify candidates involved in TORC1-mediated endocytosis, we deleted multiple genes that are involved in TORC signaling, receptor endocytosis, and CME. Casein kinases ( , , ), α-arrestins ( , , , ), and epsin-like proteins ( , ) are all involved in priming the pheromone receptors for CME during mating. CME utilizes motors and cytoskeletal organizers ( , ) to form then endocytic pit that matures into an endosome. During starvation, TORC1 activity is reduced, downregulating PP2A activity . TORC2 activates Ypk1 and Ypk2 ( , , ), which repress major cell regulators such as calcineurin . B , quantification of mean Ste2-mEnvy on the plasma membrane in the indicated strain, with or without 0.2 μM rapamycin for 2 h (n > 170 cells). Measurements were normalized to the mean of the untreated groups to produce percentages. One-way ANOVA was used to analyze variance between treated and untreated mutant and WT cells. Tukey’s HSD test was used as a multiple comparison test to compare means between groups. Based on ANOVA results, genetic mutants treated with rapamycin were grouped into one of three categories: no rescue ( red ), partial rescue ( yellow ), and complete rescue ( green ). Mutants in the no rescue category were only significantly different ( p < 0.05) from untreated WT cells. Mutants in the partial rescue category were significantly different from both treated and untreated WT cells. Mutants in the complete rescue category were only significantly different from rapamycin-treated WT cells. Error bars represent ±SEM. Bars with dashed outlines show data reported in E . C – G , representative images of ( C ) WT, ( D ) end 3Δ, ( E ) rog Δ, ( F ) rod 1Δ, and ( G ) ypk 1Δ cells expressing Ste2-mEnvy treated with or without 0.2 μM rapamycin for 2 h. Scale bars represent 4 μm. CME, clathrin-mediated endocytosis; HSD, honestly significant difference; mEnvy, monomeric Envy; TORC, target of rapamycin complex.
Article Snippet: To repress TORC1 activity with rapamycin (0215934691, MP Biomedicals), cells were treated with 0.2 μM rapamycin suspended in ethanol for 2 h prior to imaging.
Techniques: Inhibition, Activity Assay, Clinical Proteomics, Membrane, Mutagenesis, Comparison, Expressing