The Heterotrimeric G-Protein GanB(α)-SfaD(β)-GpgA(γ) Is a Carbon Source Sensor Involved in Early cAMP-Dependent Germination inAspergillus nidulans
- 1 September 2005
- journal article
- Published by Oxford University Press (OUP) in Genetics
- Vol. 171 (1) , 71-80
- https://doi.org/10.1534/genetics.105.040584
Abstract
The role of heterotrimeric G-proteins in cAMP-dependent germination of conidia was investigated in the filamentous ascomycete Aspergillus nidulans. We demonstrate that the Gα-subunit GanB mediates a rapid and transient activation of cAMP synthesis in response to glucose during the early period of germination. Moreover, deletion of individual G-protein subunits resulted in defective trehalose mobilization and altered germination kinetics, indicating that GanB(α)-SfaD(β)-GpgA(γ) constitutes a functional heterotrimer and controls cAMP/PKA signaling in response to glucose as well as conidial germination. Further genetic analyses suggest that GanB plays a primary role in cAMP/PKA signaling, whereas the SfaD-GpgA (Gβγ) heterodimer is crucial for proper activation of GanB signaling sensitized by glucose. In addition, the RGS protein RgsA is also involved in regulation of the cAMP/PKA pathway and germination via attenuation of GanB signaling. Genetic epistatic analyses led us to conclude that all controls exerted by GanB(α)-SfaD(β)-GpgA(γ) on conidial germination are mediated through the cAMP/PKA pathway. Furthermore, GanB may function in sensing various carbon sources and subsequent activation of downstream signaling for germination.Keywords
This publication has 52 references indexed in Scilit:
- Multiple Roles of a Heterotrimeric G-Protein γ-Subunit in Governing Growth and Development of Aspergillus nidulansGenetics, 2005
- Glucose and Sucrose Act as Agonist and Mannose as Antagonist Ligands of the G Protein-Coupled Receptor Gpr1 in the Yeast Saccharomyces cerevisiaeMolecular Cell, 2004
- The GanB Gα-Protein Negatively Regulates Asexual Sporulation and Plays a Positive Role in Conidial Germination in Aspergillus nidulansSequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession no. AF198116.Genetics, 2004
- Regulators of G‐protein signalling in Aspergillus nidulans: RgsA downregulates stress response and stimulates asexual sporulation through attenuation of GanB (Gα) signallingMolecular Microbiology, 2004
- A putative G protein‐coupled receptor negatively controls sexual development in Aspergillus nidulansMolecular Microbiology, 2004
- The Gα Protein Gpa2 Controls Yeast Differentiation by Interacting with Kelch Repeat Proteins that Mimic Gβ SubunitsMolecular Cell, 2002
- Comparison of Morphogenetic Networks of Filamentous Fungi and YeastFungal Genetics and Biology, 2001
- Fungal Spore Germination: Insights from the Molecular Genetics ofAspergillus nidulansandNeurospora crassaFungal Genetics and Biology, 1997
- Regulation of the cAMP Level in the Yeast Saccharomyces cerevisiae: the Glucose-induced cAMP Signal Is Not Mediated by a Transient Drop in the Intracellular pHMicrobiology, 1987
- Germination studies on pure yeast ascosporesCanadian Journal of Microbiology, 1974