Characterization of the rax1 gene encoding a putative regulator of G protein signaling in Aspergillus fumigatus

We have identified a gene encoding RGS domain-containing protein kinase (RCK1), a novel regulator of G protein signaling domain-containing protein kinase. RCK1 mutant strains exhibit strong aggregation and chemotaxis defects. rck1 null cells chemotax ∼50% faster than wild-type cells, suggesting RCK1 plays a negative regulatory role in chemotaxis. Consistent with this finding, overexpression of wild-type RCK1 reduces chemotaxis speed by ∼40%. On cAMP stimulation, RCK1 transiently translocates to the membrane/cortex region with membrane localization peaking at ∼10 s, similar to the kinetics of membrane localization of the pleckstrin homology domain-containing proteins CRAC, Akt/PKB, and PhdA. RCK1 kinase activity also increases dramatically. The RCK1 kinase activity does not rapidly adapt, but decreases after the cAMP stimulus is removed. This is particularly novel considering that most other chemoattractant-activated kinases (e.g., Akt/PKB, ERK1, ERK2, and PAKa) rapidly adapt after activation. Using site-directed mutagenesis, we further show that both the RGS and kinase domains are required for RCK1 function and that RCK1 kinase activity is required for the delocalization of RCK1 from the plasma membrane. Genetic evidence suggests RCK1 function lies downstream from Gα2, the heterotrimeric G protein that couples to the cAMP chemoattractant receptors. We suggest that RCK1 might be part of an adaptation pathway that regulates aspects of chemotaxis in Dictyostelium.

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Characteristics of a Regulator of G-Protein Signaling (RGS) rgsC in Aspergillus fumigatus

Frontiers in Microbiology ◽

10.3389/fmicb.2017.02058 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 9

Author(s):

Young Kim ◽

In-Beom Heo ◽

Jae-Hyuk Yu ◽

Kwang-Soo Shin

Keyword(s):

Aspergillus Fumigatus ◽

G Protein ◽

G Protein Signaling ◽

Protein Signaling

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Molecular Cloning of Regulators of G-Protein Signaling Family Members and Characterization of Binding Specificity of RGS 12 PDZ Domain

G Protein Pathways, Part B: G Proteins and their Regulators - Methods in Enzymology ◽

10.1016/s0076-6879(02)44752-0 ◽

2002 ◽

pp. 740-761 ◽

Cited By ~ 22

Author(s):

Bryan E. Snow ◽

Greg M. Brothers ◽

David P. Siderovski

Keyword(s):

Molecular Cloning ◽

G Protein ◽

Pdz Domain ◽

Family Members ◽

Binding Specificity ◽

G Protein Signaling ◽

Protein Signaling

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Heterotrimeric G-Protein Signalers and RGSs in Aspergillus fumigatus

Pathogens ◽

10.3390/pathogens9110902 ◽

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.

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G-Protein Signaling Mediates Asexual Development at 25°C but Has No Effect on Yeast-Like Growth at 37°C in the Dimorphic Fungus Penicillium marneffei

Eukaryotic Cell ◽

10.1128/ec.1.3.440-447.2002 ◽

2002 ◽

Vol 1 (3) ◽

pp. 440-447 ◽

Cited By ~ 39

Author(s):

Sophie Zuber ◽

Michael J. Hynes ◽

Alex Andrianopoulos

Keyword(s):

G Protein ◽

Regulatory Gene ◽

Penicillium Marneffei ◽

Yeast Cells ◽

Asexual Development ◽

Protein Signaling ◽

Dimorphic Fungus ◽

Gene Encoding ◽

Opportunistic Human Pathogen

ABSTRACT The ascomycete Penicillium marneffei is an opportunistic human pathogen exhibiting a temperature-dependent dimorphic switch. At 25°C, P. marneffei grows as filamentous multinucleate hyphae and undergoes asexual development, producing uninucleate spores. At 37°C, it forms uninucleate yeast cells which divide by fission. We have cloned a gene encoding a Gα subunit of a heterotrimeric G protein from P. marneffei named gasA with high similarity to fadA in Aspergillus nidulans. Through the characterization of a ΔgasA strain and mutants carrying a dominant activating or a dominant interfering gasA allele, we show that GasA is a key regulator of asexual development but seems to play no role in the regulation of growth. A dominant activating gasA mutant whose mutation results in a G42-to-R change (gasA G42R) does not express brlA, the conidiation-specific regulatory gene, and is locked in vegetative growth, while a dominant interfering gasA G203R mutant shows inappropriate brlA expression and conidiation. Interestingly, the gasA mutants have no apparent defect in dimorphic switching or yeast-like growth at 37°C. Growth tests on dibutyryl cyclic AMP (dbcAMP) and theophylline suggest that a cAMP-protein kinase A cascade may be involved in the GasA signaling pathway.

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