
ABSTRACT Target-of-rapamycin proteins (TORs) are Ser/Thr kinases serving a central role in cell growth control. TORs function in two conserved multiprotein complexes, TOR complex 1 (TORC1) and TORC2; the mechanisms underlying their actions and regulation are not fully elucidated. Saccharomyces TORC2, containing Tor2p, Avo1p, Avo2p, Avo3p/Tsc11p, Bit61p, and Lst8p, regulates cell integrity and actin organization. Two classes of avo3 temperature-sensitive ( avo3 ts ) mutants that we previously identified display cell integrity and actin defects, yet one is suppressed by AVO1 while the other is suppressed by AVO2 or SLM1 , defining two TORC2 downstream signaling mechanisms, one mediated by Avo1p and the other by Avo2p/Slm1p. Employing these mutants, we explored Avo3p functions in TORC2 structure and signaling. By observing binary protein interactions using coimmunoprecipitation, we discovered that the composition of TORC2 and its recruitment of the downstream effectors Slm1p and Slm2p were differentially affected in different avo3 ts mutants. These molecular defects can be corrected only by expressing AVO3 , not by expressing suppressors, highlighting the role of Avo3p as a structural and signaling scaffold for TORC2. Phenotypic modifications of avo3 ts mutants by deletion of individual Rho1p-GTPase-activating proteins indicate that two TORC2 downstream signaling branches converge on Rho1p activation. Our results also suggest that Avo2p/Slm1p-mediated signaling, but not Avo1p-mediated signaling, links to Rho1p activation specifically through the Rho1p-guanine nucleotide exchange factor Tus1p.
Transcriptional Activation, rho GTP-Binding Proteins, Saccharomyces cerevisiae Proteins, Macromolecular Substances, RNA-Binding Proteins, Cell Cycle Proteins, Saccharomyces cerevisiae, Cytoskeletal Proteins, Phosphatidylinositol 3-Kinases, Gene Expression Regulation, Fungal, Mutation, Guanine Nucleotide Exchange Factors, Carrier Proteins, Signal Transduction
Transcriptional Activation, rho GTP-Binding Proteins, Saccharomyces cerevisiae Proteins, Macromolecular Substances, RNA-Binding Proteins, Cell Cycle Proteins, Saccharomyces cerevisiae, Cytoskeletal Proteins, Phosphatidylinositol 3-Kinases, Gene Expression Regulation, Fungal, Mutation, Guanine Nucleotide Exchange Factors, Carrier Proteins, Signal Transduction
| citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 15 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
