One motif to bind them: A small-XXX-small motif affects transmembrane domain 1 oligomerization, function, localization, and cross-talk between two yeast GPCRs
| Autor: | Ann M. Dixon, Antonia Lock, Leo Bowsher, Rachel Forfar, Graham Ladds, Cathryn Weston, Graham J. G. Upton, Christopher A. Reynolds |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Trafficking
biology G protein Saccharomyces cerevisiae Biophysics Cross-talk Cell Biology biology.organism_classification Biochemistry Signaling Cell biology Transmembrane domain GPCR TOXCAT Membrane protein Schizosaccharomyces pombe Oligomerization Structural motif Sequence motif G protein-coupled receptor |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1838(12):3036-3051 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/j.bbamem.2014.08.019 |
| Popis: | G protein-coupled receptors (GPCRs) are the largest family of cell-surface receptors in mammals and facilitate a range of physiological responses triggered by a variety of ligands. GPCRs were thought to function as monomers, however it is now accepted that GPCR homo- and hetero-oligomers also exist and influence receptor properties. The Schizosaccharomyces pombe GPCR Mam2 is a pheromone-sensing receptor involved in mating and has previously been shown to form oligomers in vivo. The first transmembrane domain (TMD) of Mam2 contains a small-XXX-small motif, overrepresented in membrane proteins and well-known for promoting helix–helix interactions. An ortholog of Mam2 in Saccharomyces cerevisiae, Ste2, contains an analogous small-XXX-small motif which has been shown to contribute to receptor homo-oligomerization, localization and function. Here we have used experimental and computational techniques to characterize the role of the small-XXX-small motif in function and assembly of Mam2 for the first time. We find that disruption of the motif via mutagenesis leads to reduction of Mam2 TMD1 homo-oligomerization and pheromone-responsive cellular signaling of the full-length protein. It also impairs correct targeting to the plasma membrane. Mutation of the analogous motif in Ste2 yielded similar results, suggesting a conserved mechanism for assembly. Using co-expression of the two fungal receptors in conjunction with computational models, we demonstrate a functional change in G protein specificity and propose that this is brought about through hetero-dimeric interactions of Mam2 with Ste2 via the complementary small-XXX-small motifs. This highlights the potential of these motifs to affect a range of properties that can be investigated in other GPCRs. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect