Magnificent seven: roles of G protein-coupled receptors in extracellular sensing in fungi

Abstract

G protein-coupled receptors (GPCRs) represent the largest family of transmembrane receptors and are responsible for transducing extracellular signals into intracellular responses that involve complex intracellular-signaling networks. This review highlights recent research advances in fungal GPCRs, including classification, extracellular sensing, and G protein-signaling regulation. The involvement of GPCRs in pheromone and nutrient sensing has been studied extensively over the past decade. Following recent advances in fungal genome sequencing projects, a panoply of GPCR candidates has been revealed and some have been documented to play key roles sensing diverse extracellular signals, such as pheromones, sugars, amino acids, nitrogen sources, and even photons. Identification and deorphanization of additional putative GPCRs may require the development of new research tools. Here, we compare research on GPCRs in fungi with information derived from mammalian systems to provide a useful road map on how to better understand ligand–GPCR–G protein interactions in general. We also emphasize the utility of yeast as a discovery tool for systemic studies of GPCRs from other organisms.

Novel Approaches to Improve Cellulase Biosynthesis for Biofuel Production – Adjusting Signal Transduction Pathways in the Biotechnological Workhorse Trichoderma reesei

“…However, an early screening for signal transduction genes involved in regulation of cellulase gene expression, identified a pheromone precursor gene in T. reesei (Schmoll et al, 2004). This signal -indicating the presence of a potential mating partner -is transmitted by the heterotrimeric G protein pathway (Bölker & Kahmann, 1993;Li et al, 2007;Xue et al, 2008), which was already shown to be important for cellulase regulation Seibel et al, 2009;Tisch et al, 2011a). This is in agreement with the assumption that a shared signalling pathway may also lead to shared output effects.…”

“…They belong to six classes: Ste2-like pheromone receptors, Ste3-like pheromone receptors, carbon/amino acid receptors, putative nutrient receptors, cAMP receptor-like and microbial opsins (Xue et al, 2008), not including the PTH11-like receptors first identified in Magnaporthe grisea and involved in pathogenicity (Kulkarni et al, 2005). So far, only nutrients, pheromones and light could be confirmed as activating ligands of GPCRs Xue et al, 2008). The transmitting factors, the G protein alpha subunits, are classified in three groups (I, II, III) with group I and III being similar to mammalian G alphai and G alpha-s subunits.…”

Specific adaptation of Ustilaginoidea virens in occupying host florets revealed by comparative and functional genomics

“…In phytopathogenic fungi, G-protein-coupled receptors (GPCRs) and G-proteins are important components of signalling pathways for response to environmental stimuli 31 . U. virens, similar to the non-pathogenic saprophyte N. crassa, encodes fewer GPCRs than the hemi-biotrophic pathogens M. oryzae and F. graminearum (Supplementary Table 16, Supplementary Note 7).…”

Fungal sensing of host environment

“…Furthermore, in yeasts and other fungi, the pathway for sensing of nutrients is linked to pheromone responsiveness, which makes sense, as mating is a very energy intensive process (Schmidt, 2013;Willhite et al, 2014). G-Protein coupled receptors (GPCRs) are a family of transmembrane receptors, which are important in mediating sensing and signal transduction in response to pheromones and nutrients in many fungi (Xue et al, 2008). Because the use of GPCRs for sensing of environmental cues is evolutionary conserved, it is not surprising that they can be found even in plants .…”