scholarly journals Comparative Characterization of G Protein α Subunits in Aspergillus fumigatus

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 272 ◽  
Author(s):  
Yong-Ho Choi ◽  
Na-Young Lee ◽  
Sung-Su Kim ◽  
Hee-Soo Park ◽  
Kwang-Soo Shin
Keyword(s):  
Protein Kinase ◽  
Aspergillus Fumigatus ◽  
Mrna Expression ◽  
Signaling Pathway ◽  
G Protein ◽  
G Proteins ◽  
Asexual Development ◽  
Pkc Signaling ◽  
Α Subunits ◽  
G Protein Α Subunits

Trimeric G proteins play a central role in the G protein signaling in filamentous fungi and Gα subunits are the major component of trimeric G proteins. In this study, we characterize three Gα subunits in the human pathogen Aspergillus fumigatus. While the deletion of gpaB and ganA led to reduced colony growth, the growth of the ΔgpaA strain was increased in minimal media. The germination rate, conidiation, and mRNA expression of key asexual development regulators were significantly decreased by the loss of gpaB. In contrast, the deletion of gpaA resulted in increased conidiation and mRNA expression levels of key asexual regulators. The deletion of gpaB caused a reduction in conidial tolerance against H2O2, but not in paraquat (PQ). Moreover, the ΔgpaB mutant showed enhanced susceptibility against membrane targeting azole antifungal drugs and reduced production of gliotoxin (GT). The protein kinase A (PKA) activity of the ΔganA strain was severely decreased and protein kinase C (PKC) activity was detected all strains at similar levels, indicating that all G protein α subunits of A. fumigatus may be a component of the cAMP/PKA signaling pathway and appear to possess the PKC signaling pathway as an alternative backup pathway to compensate for PKA depletion. Collectively, the three Gα subunits regulate growth, germination, asexual development, resistance to oxidative stress, and GT production differently via the PKA or PKC signaling pathway. The function of GanA of A. fumigatus was elucidated for the first time.

scholarly journals Heterotrimeric G-Protein Signalers and RGSs in Aspergillus fumigatus

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 902
Author(s):  
Hee-Soo Park ◽  
Min-Ju Kim ◽  
Jae-Hyuk Yu ◽  
Kwang-Soo Shin
Keyword(s):  
Aspergillus Fumigatus ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
G Protein ◽  
G Proteins ◽  
Pathogenic Fungus ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Heterotrimeric G Protein ◽  
External Signals

The heterotrimeric G-protein (G-protein) signaling pathway is one of the most important signaling pathways that transmit external signals into the inside of the cell, triggering appropriate biological responses. The external signals are sensed by various G-protein-coupled receptors (GPCRs) and transmitted into G-proteins consisting of the α, β, and γ subunits. Regulators of G-protein signaling (RGSs) are the key controllers of G-protein signaling pathways. GPCRs, G-proteins, and RGSs are the primary upstream components of the G-protein signaling pathway, and they are highly conserved in most filamentous fungi, playing diverse roles in biological processes. Recent studies characterized the G-protein signaling components in the opportunistic pathogenic fungus Aspergillus fumigatus. In this review, we have summarized the characteristics and functions of GPCRs, G-proteins, and RGSs, and their regulatory roles in governing fungal growth, asexual development, germination, stress tolerance, and virulence in A. fumigatus.

Morphine-induced place preference affects mRNA expression of G protein α subunits in rat brain

2012 ◽  
Vol 64 (3) ◽  
pp. 546-557 ◽  
Author(s):  
Agnieszka Zelek-Molik ◽  
Adam Bielawski ◽  
Grzegorz Kreiner ◽  
Piotr Popik ◽  
Jerzy Vetulani ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Rat Brain ◽  
G Protein ◽  
Place Preference ◽  
Α Subunits ◽  
G Protein Α Subunits

Hormone signalling via G-protein: regulation of phosphatidylinositol 4,5-bisphosphate hydrolysis by G q

1992 ◽  
Vol 336 (1276) ◽  
pp. 35-42 ◽  
Keyword(s):  
Phospholipase C ◽  
G Protein ◽  
G Proteins ◽  
Regulatory Proteins ◽  
Affinity Reagents ◽  
Surface Receptors ◽  
New Class ◽  
Α Subunits ◽  
Hormone Signalling ◽  
G Protein Α Subunits

Heterotrimeric GTP-dependent regulatory proteins (G-proteins) mediate modulation by many cell surface receptors. Activation of the G-proteins promotes dissociation of their α and βγ subunits. The similarity of behaviour of βγ subunits derived from a variety of G-proteins has led to their use as affinity reagents for the analysis of the more unique a subunits. The evolution of these uses is presented. One of the more insightful results was the isolation of a new class of G -protein α subunits (the α q subfamily) which have been shown to regulate the activity of a phospholipase C (PLC) specific for phosphatidylinositols. The experimental evidence leading to this conclusion is discussed. The activation by α q increases the apparent V max of the β isoform of phosphatidylinositol-specific phospholipase C (PLCβ) and can be modulated by βγ subunits.

scholarly journals Genetic Involvement of a cAMP-Dependent Protein Kinase in a G Protein Signaling Pathway Regulating Morphological and Chemical Transitions in Aspergillus nidulans

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 591-600
Author(s):  
Kiminori Shimizu ◽  
Nancy P Keller
Keyword(s):  
Protein Kinase ◽  
Aspergillus Nidulans ◽  
Signaling Pathway ◽  
G Protein ◽  
Radial Growth ◽  
Morphological Development ◽  
Dependent Protein Kinase ◽  
Α Subunit ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

Abstract In the filamentous fungus Aspergillus nidulans, a heterotrimeric G protein α-subunit and an RGS domain protein, encoded by fadA and flbA, respectively, regulate production of the carcinogenic metabolite sterigmatocystin (ST) and asexual spores (i.e., conidia). We investigated the genetic involvement of the cAMP-dependent protein kinase catalytic subunit (PkaA), a potential downstream target of FadA activity, in ST production and conidiation. Relative to wild type, sporulation was decreased in the pkaA overexpression strain but was not totally absent, as occurs in ΔflbA or fadAG42R (fadA-dominant active) strains. Deletion of pkaA resulted in a hyper-conidiating strain with limited radial growth. This phenotype was epistatic to mutation in flbA or fadA; the double mutants ΔpkaA; ΔflbA and ΔpkaA; fadAG42R recovered sporulation and their radial growth was severely restricted. PkaA overexpression also negatively regulated AflR, the ST biosynthesis-specific transcription factor, both transcriptionally and post-transcriptionally. Deletion of pkaA restored ST production in the ΔflbA background but not in the fadAG42R background. These data provide genetic evidence that the FlbA/FadA signaling pathway regulating ST production and morphological development is partially mediated through PkaA.

scholarly journals Genes for two homologous G-protein α subunits map to different human chromosomes

1987 ◽  
Vol 77 (3) ◽  
pp. 259-262 ◽  
Author(s):  
Eva J. Neer ◽  
Thomas Michel ◽  
Roger Eddy ◽  
Thomas Shows ◽  
J. G. Seidman
Keyword(s):  
G Protein ◽  
Human Chromosomes ◽  
Α Subunits ◽  
G Protein Α Subunits

[25] Palmitoylation of G-protein α subunits

1995 ◽  
pp. 314-330 ◽  
Author(s):  
Maurine E. Linder ◽  
Christiane Kleuss ◽  
Susanne M. Mumby
Keyword(s):  
G Protein ◽  
Α Subunits ◽  
G Protein Α Subunits

Calcium signaling in rat pancreatic acinar cells: a role for Gαq, Gα11, and Gα14

1999 ◽  
Vol 276 (1) ◽  
pp. G271-G279 ◽  
Author(s):  
David I. Yule ◽  
Christopher W. Baker ◽  
John A. Williams
Keyword(s):  
Cell Line ◽  
G Protein ◽  
Cho Cells ◽  
Acinar Cells ◽  
Cell Types ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Pcr Products ◽  
Α Subunits ◽  
G Protein Α Subunits

Stimulus-secretion coupling in the pancreatic acinar cell is initiated by the secretagogues CCK and ACh and results in the secretion by exocytosis of the contents of zymogen granules. A key event in this pathway is the G protein-activated production of second messengers and the subsequent elevation of cytosolic-free Ca2+. The aim of this study was therefore to define the heterotrimeric G protein α-subunits present and participating in this pathway in rat pancreatic acinar cells. RT-PCR products were amplified from pancreatic acinar cell mRNA with primers specific for Gαq, Gα11, and Gα14 but were not amplified with primers specific for Gα15. The sequences of these PCR products confirmed them to be portions of the rat homologues of Gαq, Gα11, and Gα14. The pancreatic-derived cell line AR42J similarly expressed Gαq, Gα11, and Gα14; however, the Chinese hamster ovary (CHO) cell line only expressed Gα11 and Gαq. These data indicate that caution should be exercised when comparing signal transduction pathways between different cell types. The expression of these proteins in acinar cells was confirmed by immunoblotting samples of acinar membrane protein using specific antisera to the individual G protein α-subunits. The role of these proteins in Ca2+ signaling events was investigated by microinjecting a neutralizing antibody directed against a homologous sequence in Gαq, Gα11, and Gα14 into acinar cells and CHO cells. Ca2+ signaling was inhibited in acinar cells and receptor-bearing CHO cells in response to both physiological and supermaximal concentrations of agonists. The inhibition was >75% in both cell types. These data indicate a role for Gαq and/or Gα11 in intracellular Ca2+ concentration signaling in CHO cells, and in addition to Gαq and Gα11, Gα14 may also fulfill this role in rat pancreatic acinar cells.

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