A putative G protein-coupled receptor negatively controls sexual development in Aspergillus nidulans.
G protein-coupled receptors (GPCRs) are key components of heterotrimeric G protein-mediated signalling pathways that detect environmental signals and confer rapid cellular responses. To broaden our understanding of signalling mechanisms in the filamentous fungus Aspergillus nidulans, intensive analyses of the Aspergillus nidulans genome have been carried out and nine genes (gprA approximately gprI) that are predicted to encode seven transmembrane spanning GPCRs have been identified. Six of nine putative GPCRs have been disrupted and the gprD gene was found to play a central role in coordinating hyphal growth and sexual development. Deletion of gprD (Delta gprD) causes extremely restricted hyphal growth, delayed conidial germination and uncontrolled activation of sexual development resulting in a small colony covered by sexual fruiting bodies. Genetic studies indicate that GprD may not signal through the FadA (G alpha)-protein kinase A (PKA) pathway. Elimination of sexual development rescues both growth and developmental abnormalities caused by Delta gprD, suggesting that the primary role of GprD is to negatively regulate sexual development. This is supported by the fact that environmental conditions inhibiting sexual development suppress growth defects of the Delta gprD mutant. We propose that the GprD-mediated signalling cascade negatively regulates sexual development, which is required for proper proliferation of A. nidulans.
Han
Kap-Hoon
KH
Department of Food Microbiology and Toxicology and Food Research Institute, Molecular and Environmental Toxicology Center, 1925 Willow Drive, University of Wisconsin, Madison, 53706, USA.
Seo
Jeong-Ah
JA
Yu
Jae-Hyuk
JH
D000595:Amino Acid Sequence; D000818:Animals; D001233:Aspergillus nidulans / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D011493:Protein Kinase C / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology; D013696:Temperature
D005656:Fungal Proteins; D043562:Receptors, G-Protein-Coupled; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D020962:Heterotrimeric GTP-Binding Proteins