| Title: | N-terminal intrinsic disorder is an ancestral feature of Ggamma subunits that influences the balance between different Gbetagamma signaling axes in yeast |
| Author(s): | Su X; Pang YT; Li W; Gumbart JC; Kelley J; Torres M; |
| Address: | "School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA. School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA. School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA; Southeast Center for Mathematics and Biology, Georgia Institute of Technology, Atlanta, Georgia, USA. Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, USA. School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA; Southeast Center for Mathematics and Biology, Georgia Institute of Technology, Atlanta, Georgia, USA. Electronic address: mtorres35@gatech.edu" |
| DOI: | 10.1016/j.jbc.2023.104947 |
| ISSN/ISBN: | 1083-351X (Electronic) 0021-9258 (Print) 0021-9258 (Linking) |
| Abstract: | "Activated G protein-coupled receptors promote the dissociation of heterotrimeric G proteins into Galpha and Gbetagamma subunits that bind to effector proteins to drive intracellular signaling responses. In yeast, Gbetagamma subunits coordinate the simultaneous activation of multiple signaling axes in response to mating pheromones, including MAP kinase (MAPK)-dependent transcription, cell polarization, and cell cycle arrest responses. The Ggamma subunit in this complex contains an N-terminal intrinsically disordered region that governs Gbetagamma-dependent signal transduction in yeast and mammals. Here, we demonstrate that N-terminal intrinsic disorder is likely an ancestral feature that has been conserved across different Ggamma subtypes and organisms. To understand the functional contribution of structural disorder in this region, we introduced precise point mutations that produce a stepwise disorder-to-order transition in the N-terminal tail of the canonical yeast Ggamma subunit, Ste18. Mutant tail structures were confirmed using circular dichroism and molecular dynamics and then substituted for the wildtype gene in yeast. We find that increasing the number of helix-stabilizing mutations, but not isometric mutation controls, has a negative and proteasome-independent effect on Ste18 protein levels as well as a differential effect on pheromone-induced levels of active MAPK/Fus3, but not MAPK/Kss1. When expressed at wildtype levels, we further show that mutants with an alpha-helical N terminus exhibit a counterintuitive shift in Gbetagamma signaling that reduces active MAPK/Fus3 levels whilst increasing cell polarization and cell cycle arrest. These data reveal a role for Ggamma subunit intrinsically disordered regions in governing the balance between multiple Gbetagamma signaling axes" |
| Keywords: | *GTP-Binding Protein beta Subunits/genetics/metabolism *GTP-Binding Protein gamma Subunits/genetics/metabolism Mitogen-Activated Protein Kinases/metabolism Mutation Saccharomyces cerevisiae/genetics/metabolism *Signal Transduction Amino Acid Substitution; |
| Notes: | "MedlineSu, Xinya Pang, Yui Tik Li, Wei Gumbart, J C Kelley, Joshua Torres, Matthew eng R01 GM117400/GM/NIGMS NIH HHS/ R01 GM123169/GM/NIGMS NIH HHS/ R15 GM140409/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2023/06/25 J Biol Chem. 2023 Aug; 299(8):104947. doi: 10.1016/j.jbc.2023.104947. Epub 2023 Jun 22" |
