A putative G protein‐coupled receptor negatively controls sexual development in Aspergillus nidulans

• Published in: Molecular microbiology Vol. 51; no. 5; pp. 1333 - 1345
• Main Authors: Han, Kap‐Hoon, Seo, Jeong‐Ah, Yu, Jae‐Hyuk
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.03.2004; Blackwell Science; Blackwell Publishing Ltd
• Subjects: Amino Acid Sequence; Animals; Aspergillus nidulans; Aspergillus nidulans - cytology; Aspergillus nidulans - genetics; Aspergillus nidulans - growth & development; Aspergillus nidulans - physiology; Biological and medical sciences; Cyclic AMP-Dependent Protein Kinases - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; Genes, Fungal; Heterotrimeric GTP-Binding Proteins - metabolism; Microbiology; Miscellaneous; Molecular Sequence Data; Mutation; Mycology; Phenotype; Phylogeny; Protein Kinase C - metabolism; Receptors, G-Protein-Coupled - classification; Receptors, G-Protein-Coupled - genetics; Receptors, G-Protein-Coupled - metabolism; Sequence Alignment; Signal Transduction - physiology; Temperature; Fungi; Microbiology; Aspergillus nidulans; Development; Fungi Imperfecti; Thallophyta; G protein
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2003.03940.x

Summary 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∼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 (ΔgprD) 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 (Gα)‐protein kinase A (PKA) pathway. Elimination of sexual development rescues both growth and developmental abnormalities caused by ΔgprD, 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 ΔgprD mutant. We propose that the GprD‐mediated signalling cascade negatively regulates sexual development, which is required for proper proliferation of A. nidulans.