fadA encodes the alpha subunit of the principal heterotrimeric G protein of Aspergillus nidulans. GTP-bound (active) FadA promotes vegetative (hyphal) proliferation and represses asexual sporulation and secondary metabolism; its signaling is attenuated by the RGS protein FlbA, which licenses conidiation. FadA (with the Gbeta SfaD and Ggamma GpgA) thus sits at the growth/development decision point, and also modulates sterigmatocystin and penicillin production and sexual development.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003925 G protein activity | IBA GO_REF:0000033 | ACCEPT | Summary: Accept: G protein activity. Reason: The IBA call places FadA in the G-alpha clade, and GO:0003925 covers exactly the GTP-binding/hydrolysing signal-transducer role of a G-alpha subunit. This is FadA's core molecular function. |
| GO:0005737 cytoplasm | IBA GO_REF:0000033 | ACCEPT | Summary: Accept: cytoplasm. Reason: G-alpha subunits act on the cytoplasmic face of the plasma membrane, so an is_active_in cytoplasm call is compatible; the term is unspecific, and the informative location for FadA is the heterotrimer (GO:0005834). |
| GO:0005834 heterotrimeric G-protein complex | IBA GO_REF:0000033 | ACCEPT | Summary: Accept: heterotrimeric G-protein complex. Reason: Complex membership is the primary structural statement for a G-alpha subunit: FadA partners the G-beta SfaD and the G-gamma GpgA, both of which are independently annotated to this complex. |
| GO:0001664 G protein-coupled receptor binding | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: G protein-coupled receptor binding. Reason: Receptor coupling is the defining interaction of a G-alpha subunit. The call is a family-level electronic inference and no A. nidulans receptor-binding assay is cited in this review, but it is a sound default for the subunit that receives GPCR input. |
| GO:0003924 GTPase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Accept: GTPase activity. Reason: Assigned from the conserved G-domain signature. The fadA alleles characterised in this review are nucleotide-cycle mutants (a constitutively signalling allele and a dominant-interfering allele), which is what an intrinsically hydrolysing GTPase predicts. |
| GO:0005525 GTP binding | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: GTP binding. Reason: The P-loop and G-box motifs of the G-alpha nucleotide-binding domain support guanine-nucleotide binding; this is the ligand-binding facet of the same activity captured by GO:0003925. |
| GO:0005834 heterotrimeric G-protein complex | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: heterotrimeric G-protein complex. Reason: Reaches the same complex assignment as the IBA row by sequence similarity. Retained because the heterotrimer, not the free subunit, is the assembly in which FadA acts. |
| GO:0007165 signal transduction | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: signal transduction. Reason: Correct but very general. Kept as the parent of the informative GPCR-pathway term rather than as an independent statement of what FadA does. |
| GO:0007186 G protein-coupled receptor signaling pathway | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: G protein-coupled receptor signaling pathway. Reason: The pathway term that matches FadA's role: it transduces receptor input into the proliferation-versus-development decision. Electronic here, but the same term is independently supported by mutant evidence elsewhere in this review. |
| GO:0019001 guanyl nucleotide binding | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: guanyl nucleotide binding. Reason: Parent of GTP binding; adds no specificity over GO:0005525 but is not incorrect for a G-domain protein. |
| GO:0031683 G-protein beta/gamma-subunit complex binding | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: G-protein beta/gamma-subunit complex binding. Reason: G-alpha/G-beta-gamma association is the interaction that builds the heterotrimer; in A. nidulans the partners are SfaD and GpgA, both curated as components of the same complex. |
| GO:0048315 conidium formation | IMP PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | MODIFY | Summary: Direction should be signed. FadA signaling represses conidiation rather than driving conidium formation. Reason: The unsigned term loses the demonstrated direction. Constitutive FadA signaling (fadA(G42R)) blocks sporulation, while loss of fadA leaves sporulation intact and the dominant-interfering allele is a hyperactive sporulator, so FadA is a negative regulator of conidium formation. Proposed replacements: negative regulation of conidium formation Supporting Evidence: PMID:8895563 activation of this pathway leads to proliferation and blocks sporulation PMID:8895563 a fadA deletion and a fadA dominant-interfering mutation (fadA(G203R)) resulted in reduced growth without impairing sporulation |
| GO:0010913 regulation of sterigmatocystin biosynthetic process | IMP PMID:9305634 Aspergillus sporulation and mycotoxin production both requir... | KEEP AS NON CORE | Summary: Non-core regulatory role in sterigmatocystin biosynthesis. Reason: FadA modulates ST via G-protein signaling; pleiotropic non-core role. |
| GO:0010913 regulation of sterigmatocystin biosynthetic process | IMP PMID:9339347 Dominant mutations affecting both sporulation and sterigmato... | KEEP AS NON CORE | Summary: Non-core regulatory role in sterigmatocystin biosynthesis. Reason: Duplicate ST-regulation role; non-core. |
| GO:0044550 secondary metabolite biosynthetic process | IMP PMID:9339347 Dominant mutations affecting both sporulation and sterigmato... | MARK AS OVER ANNOTATED | Summary: Over-annotated: FadA regulates secondary metabolism, it is not a biosynthetic enzyme. Reason: FadA is a signaling G-alpha subunit, not a biosynthetic enzyme; the biosynthetic-process annotation overstates its role. Proposed replacements: regulation of secondary metabolite biosynthetic process |
| GO:0045461 sterigmatocystin biosynthetic process | IMP PMID:9305634 Aspergillus sporulation and mycotoxin production both requir... | MARK AS OVER ANNOTATED | Summary: Over-annotated: regulator of sterigmatocystin, not part of the biosynthetic pathway. Reason: This subunit influences sterigmatocystin only via G-protein signaling (regulatory); the biosynthetic-process annotation overstates the role. The regulation term is more accurate. Proposed replacements: regulation of sterigmatocystin biosynthetic process |
| GO:1900376 regulation of secondary metabolite biosynthetic process | IMP PMID:9339347 Dominant mutations affecting both sporulation and sterigmato... | KEEP AS NON CORE | Summary: Non-core secondary-metabolite regulatory role. Reason: Regulatory reach over secondary metabolism; non-core. |
| GO:0042318 penicillin biosynthetic process | IMP PMID:11069688 G-protein signalling mediates differential production of tox... | MARK AS OVER ANNOTATED | Summary: Over-annotated: FadA regulates penicillin production, it is not a biosynthetic enzyme. Reason: FadA affects penicillin biosynthesis via signaling; the regulation term is accurate. Proposed replacements: positive regulation of penicillin biosynthetic process |
| GO:1900198 positive regulation of penicillin biosynthetic process | IMP PMID:11069688 G-protein signalling mediates differential production of tox... | KEEP AS NON CORE | Summary: Non-core regulation of penicillin biosynthesis. Reason: Pleiotropic secondary-metabolism regulatory role. |
| GO:0007165 signal transduction | IMP PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: signal transduction. Reason: Mutational evidence that altering fadA activity changes the growth-versus-sporulation output, which is a signalling readout. The term is general, but the specific GPCR-pathway term is annotated separately from the same evidence. |
| GO:0000909 sporocarp development involved in sexual reproduction | IMP PMID:10523303 The Aspergillus nidulans sfaD gene encodes a G protein beta ... | KEEP AS NON CORE | Summary: Non-core role in sexual (sporocarp) development. Reason: FadA signaling also influences sexual development; non-core relative to its growth/conidiation-control function. |
| GO:0075306 regulation of conidium formation | IMP PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Core process. FadA regulates conidium formation. Reason: Active FadA represses conidiation; FadA is a key regulator of the growth/development switch. Supporting Evidence: PMID:8895563 This mutation is predicted to result in a loss of intrinsic GTPase activity leading to constitutive signaling, indicating that activation of this pathway leads to proliferation and blocks sporulation. PMID:8895563 a fadA deletion and a fadA dominant-interfering mutation (fadA(G203R)) resulted in reduced growth without impairing sporulation |
| GO:0075306 regulation of conidium formation | IGI PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Core process. FadA regulates conidium formation (genetic interaction). Reason: Genetic-interaction evidence supports FadA regulation of conidiation. |
| GO:0003924 GTPase activity | ISA PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: GTPase activity. Reason: Sequence-alignment evidence for the catalytic G domain, concordant with the nucleotide-cycle interpretation of the fadA alleles characterised in the same paper. |
| GO:0003924 GTPase activity | IMP PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: GTPase activity. Reason: Mutational support for a functioning GTPase cycle: the constitutively signalling and dominant-interfering fadA alleles behave as their predicted nucleotide states require. |
| GO:0005834 heterotrimeric G-protein complex | ISA PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: heterotrimeric G-protein complex. Reason: Sequence-based assignment of FadA to the G-alpha class and hence to the heterotrimer; concordant with the IBA and IEA rows for the same complex. |
| GO:0007186 G protein-coupled receptor signaling pathway | IMP PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: G protein-coupled receptor signaling pathway. Reason: The strongest form of this call: loss- and gain-of-signalling fadA alleles shift the balance between proliferation and sporulation, placing FadA inside the receptor-initiated pathway rather than merely resembling its components. |
| GO:0007186 G protein-coupled receptor signaling pathway | IGI PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: G protein-coupled receptor signaling pathway. Reason: Genetic-interaction support from the flbA/fadA relationship, which is the interaction that defines this pathway; an independent evidence line for the term already carried by the IMP row. |
| GO:0019001 guanyl nucleotide binding | IMP PMID:8895563 The Aspergillus FlbA RGS domain protein antagonizes G protei... | ACCEPT | Summary: Accept: guanyl nucleotide binding. Reason: Inferred from alleles whose phenotypes track nucleotide state rather than from a direct binding assay. Weaker than the IEA G-domain calls it duplicates, but concordant with them. |
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Download this section (compressed HTML)UniProt Q00743 (GPA1_EMENI / FadA). G-alpha subunit; repressive gating tier of the conidiation_regulatory_cascade module.
- Active (GTP-bound) FadA drives proliferation and represses conidiation; antagonized by the RGS protein FlbA. PMID:8895563.
- Core MF GO:0003925 G protein activity; in heterotrimeric G-protein complex (GO:0005834).
- Over-annotations flagged: GO:0045461 ST biosynthetic process, GO:0044550 secondary metabolite biosynthetic process, GO:0042318 penicillin biosynthetic process (FadA is a signaling subunit, not a biosynthetic enzyme → regulation terms).
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