D7r2 is a short-form salivary protein from female Anopheles gambiae mosquitoes that facilitates blood feeding by binding and sequestering host biogenic amines (serotonin, histamine, and norepinephrine). It functions as a "kratagonist" - capturing host signaling molecules with high affinity to prevent their vasoconstrictive, platelet-aggregating, and inflammatory effects. The protein is secreted into saliva during blood feeding. D7r2 belongs to the PBP/GOBP (Pheromone/Odorant-Binding Protein) structural family but has evolved a distinct function unrelated to olfaction.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0005615
extracellular space
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: This annotation correctly reflects the subcellular localization of D7r2 as a secreted salivary protein. The IBA annotation is based on phylogenetic inference from the PANTHER family including D7r4 (Q7PNF2) which shares the same localization.
Reason: D7r2 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q9UB31]. It is released into the extracellular space (saliva) during blood feeding. The UniProt entry confirms "SUBCELLULAR LOCATION: Secreted" (PMID:17913537) [UniProt Q9UB31]. The IBA inference is appropriate as all D7 family members share this secreted localization pattern. Deep research on the D7 family confirms "D7r1 is produced in adult female salivary glands and secreted in saliva at the skin interface during probing/feeding" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md], which applies equally to D7r2.
Supporting Evidence:
UniProt:Q9UB31
SUBCELLULAR LOCATION: Secreted
PMID:17913537
A proteomic and immunoproteomic analysis of anopheles and Aedes saliva allowed for the identification of some antigens
|
|
GO:0007608
sensory perception of smell
|
IBA
GO_REF:0000033 |
REMOVE |
Summary: This annotation is INCORRECT. While the IBA inference is based on structural family membership (PBP/GOBP-related proteins), D7r2 has no role in olfaction. The protein is expressed exclusively in female salivary glands, not olfactory tissues, and functions in blood feeding facilitation, not smell perception.
Reason: D7r2 belongs to the PBP/GOBP structural family (InterPro IPR006170), which includes olfactory proteins in other contexts. However, the D7 subfamily has evolutionarily repurposed this fold for binding biogenic amines in saliva to facilitate blood feeding, not for odorant detection. D7r2 is expressed exclusively in adult female salivary glands [PMID:11841502, PMID:9990055], not in olfactory tissues. It is not detected in male tissues or in embryo, larval, and pupal stages [PMID:11841502]. The UniProt function annotation explicitly states D7r2 "Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response" [UniProt Q9UB31] - with no mention of olfactory function. Deep research confirms short-form D7s "predominantly bind biogenic amines (serotonin/5-HT, histamine, epinephrine/norepinephrine)" not odorants [file:ANOGA/D7r1/D7r1-deep-research-falcon.md]. The IBA inference from Drosophila odorant binding proteins (FB:FBgn0011279, FB:FBgn0034468, etc.) is inappropriate as the function has diverged in mosquito D7 proteins.
Supporting Evidence:
PMID:11841502
Four genes expressed in the Anopheles gambiae adult female salivary glands
UniProt:Q9UB31
Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response
|
|
GO:0005549
odorant binding
|
IEA
GO_REF:0000002 |
MODIFY |
Summary: This annotation is based on structural family membership (PBP/GOBP family via InterPro IPR006170) but does not reflect the actual function of D7r2. The protein binds biogenic amines (serotonin, histamine, norepinephrine), not odorants, and has no role in olfaction.
Reason: D7r2 belongs to the PBP/GOBP structural family (InterPro IPR006170), which led to this IEA annotation via GO_REF:0000002. However, the D7 proteins have evolutionarily repurposed this fold for binding biogenic amines in saliva, not odorants in antennae. D7r2 is expressed exclusively in female salivary glands [PMID:11841502, PMID:9990055], not olfactory tissues. The actual molecular function is binding serotonin (GO:0051378), histamine (GO:0051381), and norepinephrine (GO:0051380). UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)" [UniProt Q9UB31]. This is a clear case where structural homology does not predict function. The GO:0005549 definition "Binding to an odorant, any substance capable of stimulating the sense of smell" does not apply - serotonin, histamine, and norepinephrine are not odorants. Deep research confirms D7 short forms "bind serotonin, histamine, and catecholamines with high affinity" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
Supporting Evidence:
UniProt:Q9UB31
Binds serotonin, noradrenaline, histamine and adrenaline
PMID:16301315
four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine
|
|
GO:0005576
extracellular region
|
IEA
GO_REF:0000044 |
ACCEPT |
Summary: This annotation correctly reflects the subcellular localization of D7r2 as a secreted salivary protein. It is appropriately broader than the more specific GO:0005615 (extracellular space) annotation.
Reason: D7r2 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q9UB31]. The UniProt entry confirms "SUBCELLULAR LOCATION: Secreted" based on PMID:17913537 [UniProt Q9UB31]. It is released into the extracellular region (saliva) during blood feeding. This IEA annotation from UniProt subcellular location vocabulary mapping (GO_REF:0000044) is accurate. Deep research confirms D7 proteins are "secreted in saliva at the skin interface during probing/feeding" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
Supporting Evidence:
UniProt:Q9UB31
SUBCELLULAR LOCATION: Secreted
|
|
GO:0042311
vasodilation
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: This annotation is appropriate. D7r2 exhibits vasodilating activity by sequestering host vasoconstrictors (serotonin, norepinephrine), thereby facilitating blood feeding.
Reason: UniProt explicitly states D7r2 "Exhibits vasodilating activity (PubMed:16301315)" and "Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction (PubMed:16301315)" [UniProt Q9UB31]. By sequestering serotonin and norepinephrine (which are vasoconstrictors), D7r2 effectively promotes vasodilation at the bite site. This IEA annotation inferred from the UniProt keyword "Vasodilator" (KW-0840) via GO_REF:0000043 is accurate. Deep research confirms D7 kratagonist function "counteracts platelet aggregation, vasoconstriction, and nociception during feeding" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
Supporting Evidence:
UniProt:Q9UB31
Exhibits vasodilating activity
PMID:16301315
Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating, and pain-inducing properties
|
|
GO:0097746
blood vessel diameter maintenance
|
IEA
GO_REF:0000043 |
KEEP AS NON CORE |
Summary: This annotation is acceptable but less informative than the vasodilation annotation. D7r2 modulates blood vessel diameter by promoting vasodilation through sequestration of vasoconstrictive amines.
Reason: D7r2 affects blood vessel diameter through its vasodilating activity - by sequestering serotonin and norepinephrine (vasoconstrictors), it promotes vessel dilation at the bite site. This IEA annotation from UniProt keyword "Vasoactive" (KW-0838) via GO_REF:0000043 is technically correct. However, this is a broader, less informative term than GO:0042311 (vasodilation), which better captures the specific mechanism. The primary function is facilitating blood feeding through kratagonism, not general blood vessel maintenance. Keeping as non-core since vasodilation (GO:0042311) is the more appropriate and specific annotation.
Supporting Evidence:
UniProt:Q9UB31
Exhibits vasodilating activity
|
|
GO:0005615
extracellular space
|
IDA
PMID:17913537 Antibody response against saliva antigens of Anopheles gambi... |
ACCEPT |
Summary: This annotation is experimentally supported by mass spectrometry identification of D7r2 in female saliva, demonstrating its localization in the extracellular space.
Reason: PMID:17913537 (Orlandi-Pradines et al., 2007) performed proteomic analysis of Anopheles gambiae saliva using mass spectrometry and identified D7r2 as a salivary protein in female mosquitoes. The UniProt entry confirms "IDENTIFICATION BY MASS SPECTROMETRY, SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY" citing PMID:17913537 [UniProt Q9UB31]. The tissue specificity annotation states "Female saliva (at protein level) (PubMed:17913537)" [UniProt Q9UB31]. This IDA annotation with direct experimental evidence is correct and more reliable than the IBA inference for the same term.
Supporting Evidence:
PMID:17913537
A proteomic and immunoproteomic analysis of anopheles and Aedes saliva allowed for the identification of some antigens
UniProt:Q9UB31
Female saliva (at protein level)
|
|
GO:0051378
serotonin binding
|
IDA
PMID:16301315 Function and evolution of a mosquito salivary protein family |
NEW |
Summary: D7r2 binds serotonin with high affinity as demonstrated by direct binding assays. This is a core molecular function that should be annotated.
Reason: UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)" [UniProt Q9UB31]. The protein has specific binding sites for serotonin (residues 31, 59, 118, 135, 138 based on homology to Q7PNF2) [UniProt Q9UB31]. PMID:16301315 demonstrated that "four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine" using isothermal microcalorimetry and smooth muscle bioassays [PMID:16301315]. This is the actual molecular function that enables kratagonism - sequestering host serotonin to prevent vasoconstriction. GO:0051378 definition "Binding to serotonin (5-hydroxytryptamine), a monoamine neurotransmitter" accurately describes this function. Deep research confirms D7 short forms "bind serotonin, histamine, and catecholamines with high affinity" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
Supporting Evidence:
UniProt:Q9UB31
Binds serotonin, noradrenaline, histamine and adrenaline
PMID:16301315
four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine
|
|
GO:0051381
histamine binding
|
IDA
PMID:16301315 Function and evolution of a mosquito salivary protein family |
NEW |
Summary: D7r2 binds histamine with high affinity as demonstrated by direct binding assays. This is a core molecular function that should be annotated.
Reason: UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)" [UniProt Q9UB31]. The protein has specific binding sites for histamine (residues 118, 135, 138 based on homology to Q7PNF2) [UniProt Q9UB31]. PMID:16301315 demonstrated that short D7 proteins bind "serotonin with high affinity, as well as histamine and norepinephrine" using isothermal microcalorimetry and smooth muscle bioassays [PMID:16301315]. This is the actual molecular function that enables sequestration of host histamine to prevent inflammation and pruritus. GO:0051381 definition "Binding to histamine, a physiologically active amine" accurately describes this function. Deep research confirms short-form D7s bind "biogenic amines (serotonin/5-HT, histamine, epinephrine/norepinephrine)" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
Supporting Evidence:
UniProt:Q9UB31
Binds serotonin, noradrenaline, histamine and adrenaline
PMID:16301315
four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine
|
|
GO:0051380
norepinephrine binding
|
IDA
PMID:16301315 Function and evolution of a mosquito salivary protein family |
NEW |
Summary: D7r2 binds norepinephrine (noradrenaline) with high affinity as demonstrated by direct binding assays. This is a core molecular function that should be annotated.
Reason: UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)" [UniProt Q9UB31]. The protein has specific binding sites for noradrenaline (residues 31, 46, 135, 138 based on homology to Q7PNF2) [UniProt Q9UB31]. UniProt also states D7r2 "Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction (PubMed:16301315)" [UniProt Q9UB31]. PMID:16301315 demonstrated that short D7 proteins bind "serotonin with high affinity, as well as histamine and norepinephrine" [PMID:16301315]. This molecular function enables sequestration of host norepinephrine to prevent vasoconstriction. GO:0051380 definition "Binding to norepinephrine... a hormone secreted by the adrenal medulla and a neurotransmitter" accurately describes this function.
Supporting Evidence:
UniProt:Q9UB31
Binds serotonin, noradrenaline, histamine and adrenaline
PMID:16301315
four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine
|
|
GO:1900047
negative regulation of hemostasis
|
IDA
PMID:16301315 Function and evolution of a mosquito salivary protein family |
NEW |
Summary: D7r2 negatively regulates host hemostasis by sequestering serotonin (which promotes platelet aggregation) and other biogenic amines. This is a core biological process annotation.
Reason: By sequestering serotonin (which promotes platelet aggregation), histamine, and norepinephrine, D7r2 negatively regulates the host hemostatic response during blood feeding. PMID:16301315 explicitly states "Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating, and pain-inducing properties" [PMID:16301315]. Deep research confirms biogenic amine scavenging "counteracts platelet aggregation, vasoconstriction, and nociception during feeding" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md]. GO:1900047 definition "Any process that stops, prevents or reduces the frequency, rate or extent of hemostasis" accurately captures this function. This is a more accurate BP annotation than vague terms. Note that the D7r1 homolog hamadarin also has anticoagulant activity via contact pathway inhibition, suggesting this family broadly inhibits hemostasis [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
Supporting Evidence:
PMID:16301315
Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating, and pain-inducing properties
file:ANOGA/D7r1/D7r1-deep-research-falcon.md
D7 proteins act as 'kratagonists' - scavenging host small-molecule mediators (amines, leukotrienes, TXA2) at the bite site to blunt vasoconstriction, platelet aggregation, pain/itch and inflammation, thereby facilitating blood feeding
|
Q: What are the specific binding affinities (Kd values) of D7r2 for serotonin, histamine, and norepinephrine, and how do they compare to D7r1 and other short-form D7 proteins?
Suggested experts: Calvo E, Ribeiro JM, Andersen JF
Q: Is there functional redundancy among the D7r1-D7r4 short-form proteins, or do they have distinct substrate preferences or tissue localization patterns?
Suggested experts: Calvo E, Mans BJ
Experiment: Generate D7r2 knockout A. gambiae using CRISPR and measure blood meal size, feeding time, and feeding success rate compared to wild-type controls. Compare to D7r1 knockouts to assess redundancy.
Hypothesis: D7r2 knockout mosquitoes will have reduced blood feeding efficiency due to host hemostatic and inflammatory responses
Type: Gene knockout and feeding assay
Experiment: Solve the crystal structure of D7r2 in complex with serotonin, histamine, and norepinephrine to identify binding site residues and compare to the published D7r4 structure (Mans et al., 2007)
Hypothesis: D7r2 has distinct binding site residues compared to D7r4 that confer substrate specificity
Type: Structural biology
provider: falcon
model: Edison Scientific Literature
cached: false
start_time: '2026-01-30T08:21:33.399779'
end_time: '2026-01-30T08:28:53.116367'
duration_seconds: 439.72
template_file: templates/gene_research_go_focused.md
template_variables:
organism: ANOGA
gene_id: D7r2
gene_symbol: D7r2
uniprot_accession: Q9UB31
protein_description: 'RecName: Full=Short form salivary protein D7R2 {ECO:0000305};
AltName: Full=D7-related 2 protein {ECO:0000312|EMBL:CAB39728.1}; Flags: Precursor;'
gene_info: Name=D7r2 {ECO:0000303|PubMed:16301315}; ORFNames=AgaP_AGAP008282 {ECO:0000312|EMBL:EAA12290.2};
organism_full: Anopheles gambiae (African malaria mosquito).
protein_family: Belongs to the PBP/GOBP family. .
protein_domains: PBP/GOBP. (IPR006170); PBP_GOBP_sf. (IPR036728); PBP_GOBP (PF01395)
provider_config:
timeout: 600
max_retries: 3
parameters:
allowed_domains: []
temperature: 0.1
citation_count: 33
BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.
DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'D7r2' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information
Please provide a comprehensive research report on the gene D7r2 (gene ID: D7r2, UniProt: Q9UB31) in ANOGA.
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Question: You are an expert researcher providing comprehensive, well-cited information.
Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies
Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.
BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.
DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'D7r2' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information
Please provide a comprehensive research report on the gene D7r2 (gene ID: D7r2, UniProt: Q9UB31) in ANOGA.
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Plan and verification
- Identity check: The target corresponds to the Anopheles gambiae short-form D7 family member D7r2 within the salivary D7 gene cluster. Population-genetic analysis explicitly maps D7-related 2 (D7r2) to AGAP008282, a salivary-gland–expressed gene in An. gambiae, consistent with the UniProt entry Q9UB31 and gene symbol provided (D7r2) (published Feb 2014; https://doi.org/10.1111/imb.12068) (arca2014positiveselectiondrives pages 2-4, arca2014positiveselectiondrives pages 4-5). The D7 proteins belong to the odorant-binding protein (OBP) superfamily/PBP-GOBP-related class (short forms ~17 kDa, single OBP-like domain; long forms ~31–35 kDa, two domains) (published Jan 2006; https://doi.org/10.1074/jbc.M510359200; published Feb 2017; https://doi.org/10.1186/s12864-017-3579-8) (calvo2006functionandevolution pages 1-1, arca2017anophelinesalivaryprotein pages 7-9, arca2017anophelinesalivaryprotein pages 9-10). The organism matches (An. gambiae), and the domain/family assignment aligns with literature.
1) Key concepts and definitions
- D7 family and kratagonism: D7 proteins are highly expressed mosquito salivary proteins derived from the OBP/PBP-GOBP fold. They act as “kratagonists,” neutralizing host hemostatic and inflammatory agonists by high-affinity binding rather than enzymatic degradation (published Feb 2017; https://doi.org/10.1186/s12864-017-3579-8) (arca2017anophelinesalivaryprotein pages 9-10, arca2017anophelinesalivaryprotein pages 7-9).
- Short vs long forms: Short-form D7s (including D7r2) are one-domain OBP-like proteins specialized for biogenic amine binding (serotonin, histamine, norepinephrine/epinephrine). Long forms contain two OBP-like domains; their N-terminal domain often binds eicosanoids (cysteinyl leukotrienes, TXA2) while the C-terminal domain can bind biogenic amines (published Jan 2006; https://doi.org/10.1074/jbc.M510359200; published Nov 2010; https://doi.org/10.1371/journal.pbio.1000547) (calvo2006functionandevolution pages 1-1, alvarenga2010thefunctionand pages 1-2, jablonka2019functionalandstructural pages 9-10).
- Gene cluster and nomenclature: In An. gambiae, eight D7 genes are clustered on chromosome arm 3R (~20 kb), comprising three long and five short (D7r1–D7r5). D7r2 forms a paralogous clade with D7r3, consistent with duplication and functional conservation in amine sequestration (published Jan 2006; https://doi.org/10.1074/jbc.M510359200; published Feb 2017; https://doi.org/10.1186/s12864-017-3579-8) (calvo2006functionandevolution pages 6-7, arca2017anophelinesalivaryprotein pages 7-9, arca2017anophelinesalivaryprotein pages 9-10).
2) Primary molecular function, ligands, structure, and localization
- Function and ligand specificity: Recombinant An. gambiae short-form D7 proteins bind biogenic amines. Across D7r paralogs, serotonin exhibits the highest affinity (low-nanomolar Kd), with stoichiometry near one binding site per protein; D7r2/D7r3 show optimized binding for catecholamines (norepinephrine/epinephrine) in addition to serotonin and histamine (published Jan 2006; https://doi.org/10.1074/jbc.M510359200) (calvo2006functionandevolution pages 2-3, calvo2006functionandevolution pages 6-7, calvo2006functionandevolution pages 5-6, mans2007thecrystalstructure pages 1-1).
- Quantitative/statistical data: Calorimetry and bioassay data indicate low-nanomolar Kd for serotonin binding and near 1:1 stoichiometry. D7 proteins account for an estimated 5–20% of total salivary protein, and salivary glands contain ~1–3 µg protein, with about half discharged during feeding (published Jan 2006; https://doi.org/10.1074/jbc.M510359200) (calvo2006functionandevolution pages 5-6, calvo2006functionandevolution pages 2-3, calvo2006functionandevolution pages 1-1).
- Structural insights: The D7 fold is all-helical and stabilized by disulfide bonds; the crystal structure of the related An. gambiae D7r4 reveals an eight-helix bundle with three disulfide bonds and a defined amine-binding pocket, supporting shared structural determinants across short D7s, including D7r2 (published Dec 2007; https://doi.org/10.1074/jbc.M706410200) (mans2007thecrystalstructure pages 1-1). Comparative studies further show that long-form D7s use the N-terminal pocket for eicosanoids and, in some species, TXA2, while the C-terminal pocket of mosquito long D7s is compatible with amine ligands (published Nov 2010; https://doi.org/10.1371/journal.pbio.1000547; published Mar 2019; https://doi.org/10.1038/s41598-019-41848-0) (alvarenga2010thefunctionand pages 1-2, jablonka2019functionalandstructural pages 9-10).
- Localization and site of action: D7r2 is salivary-gland–expressed and secreted in saliva; its action occurs at the bite site to sequester host agonists and facilitate blood feeding (published Feb 2014; https://doi.org/10.1111/imb.12068; published Jan 2006; https://doi.org/10.1074/jbc.M510359200; published Feb 2017; https://doi.org/10.1186/s12864-017-3579-8) (arca2014positiveselectiondrives pages 2-4, calvo2006functionandevolution pages 5-6, arca2017anophelinesalivaryprotein pages 7-9).
3) Biological pathways and roles in hemostasis/inflammation
- Hemostasis and inflammation modulation: By binding serotonin, histamine, and catecholamines, D7r2 counteracts vasoconstriction, increases in vascular permeability, platelet aggregation, and nociception at the feeding site, thereby promoting efficient blood intake. Functional assays with salivary D7s demonstrate antagonism of amine-induced smooth muscle contraction and prolongation effects on coagulation tests by certain paralogs, linking D7s to antihemostatic and anti-inflammatory roles (published Jan 2006; https://doi.org/10.1074/jbc.M510359200) (calvo2006functionandevolution pages 5-6, calvo2006functionandevolution pages 1-1, calvo2006functionandevolution pages 6-7, mans2007thecrystalstructure pages 1-1).
- Pathway complementarity with long D7s: Long-form D7s can sequester cysteinyl leukotrienes and TXA2, directly inhibiting platelet activation and vascular smooth muscle contraction, complementing the amine-focused kratagonism of short forms (published Nov 2010; https://doi.org/10.1371/journal.pbio.1000547; published Mar 2019; https://doi.org/10.1038/s41598-019-41848-0) (alvarenga2010thefunctionand pages 1-2, jablonka2019functionalandstructural pages 9-10).
4) Evolutionary and selection context
- Gene family evolution: D7r2/D7r3 form a conserved clade derived from duplication, with conserved amine-binding function, while D7r1/D7r4 diverged in specificity and additional activities. Short-form D7s align to the C-terminal domain of long forms and retain the OBP-like scaffold (published Jan 2006; https://doi.org/10.1074/jbc.M510359200; published Feb 2017; https://doi.org/10.1186/s12864-017-3579-8) (calvo2006functionandevolution pages 6-7, arca2017anophelinesalivaryprotein pages 7-9, arca2017anophelinesalivaryprotein pages 9-10).
- Selection metrics: Across An. gambiae populations, salivary genes show elevated nucleotide diversity relative to housekeeping genes. For D7r2 (AGAP008282), dN/dS ≈ 0.08 indicates strong purifying selection on the protein sequence despite higher non-coding diversity, consistent with functional constraint on ligand-binding residues (published Feb 2014; https://doi.org/10.1111/imb.12068) (arca2014positiveselectiondrives pages 4-5, arca2014positiveselectiondrives pages 2-4).
5) Recent developments (2023–2024) and applications
- Functional genetics in mosquitoes (long-form D7s): CRISPR/Cas9 knockouts of Aedes aegypti D7 long-form proteins (D7L1, D7L2) demonstrated prolonged probing times and reduced Plasmodium gallinaceum oocyst loads, confirming in vivo kratagonism and suggesting that reingested salivary D7s can modulate the midgut environment and pathogen infection dynamics (published Dec 2023; https://doi.org/10.1128/mbio.02289-23) (martinmartin2023aedesaegyptid7 pages 1-2, martinmartin2023aedesaegyptid7 pages 7-9, martinmartin2023aedesaegyptid7 pages 16-17).
- Salivary-protein frameworks in transmission: Complementary 2024 work on other Anopheles salivary proteins (e.g., apyrase) underscores how abundant salivary factors regulate hemostasis and can modulate malaria transmission, reinforcing the conceptual framework in which D7r2 operates at the bite and potentially upon reingestion (published Sep 2024; https://doi.org/10.1038/s41467-024-52502-3) (arca2014positiveselectiondrives pages 2-4).
- Exposure biomarkers and vaccines: Reviews and pooled analyses have advanced salivary-protein serology as exposure biomarkers, with increasing attention to D7 antigens; 2023–2024 literature strengthened the case for D7-based exposure assessment and vector-targeted vaccine strategies, including D7-derived components (e.g., reports of D7L antigens for human exposure readouts and broader salivary-antigen vaccine overviews) (published Jan 2025 review referencing 2024 developments; https://doi.org/10.3390/biom15010082) (guo2025unravelingthemolecular pages 21-21). While these items are not Anopheles D7r2-specific, they are mechanistically consistent with the D7 family’s roles and support translational applications.
6) Current applications and real-world implementations
- Serology for exposure: Antibody responses to mosquito salivary proteins are being used to infer human exposure to bites. D7 family members are among the abundant antigens considered for such assays; recent syntheses list D7s among candidate markers as methods are standardized for surveillance (published Jan 2025; https://doi.org/10.3390/biom15010082) (guo2025unravelingthemolecular pages 21-21).
- Vector-targeted vaccine concepts: Vector-saliva–based vaccines are under exploration as adjuncts to pathogen vaccines. D7-like proteins, because of their abundant expression and defined pharmacology, are frequently proposed as candidates, though clinical validation for D7r2 per se is pending (published Jan 2025; https://doi.org/10.3390/biom15010082) (guo2025unravelingthemolecular pages 21-21).
7) Expert analysis and synthesis
- Mechanistic consensus: The weight of biochemical, structural, and evolutionary evidence supports D7r2 as a short-form salivary OBP-like protein that kratagonizes biogenic amines—especially serotonin and catecholamines—at the bite site, dampening vasoconstriction, platelet activation, and inflammation. The conserved purifying selection on D7r2 coding sequence suggests functional constraints on its binding pocket and structural core (published Jan 2006; https://doi.org/10.1074/jbc.M510359200; published Dec 2007; https://doi.org/10.1074/jbc.M706410200; published Feb 2014; https://doi.org/10.1111/imb.12068) (calvo2006functionandevolution pages 2-3, calvo2006functionandevolution pages 1-1, mans2007thecrystalstructure pages 1-1, arca2014positiveselectiondrives pages 4-5, arca2014positiveselectiondrives pages 2-4).
- Pathway relevance today: 2023 genetic knockouts in Aedes confirm that D7s materially affect feeding behavior and parasite biology in vivo, strengthening the long-standing model and suggesting analogous importance for Anopheles D7s, including short forms like D7r2, at the bite site and possibly after reingestion (published Dec 2023; https://doi.org/10.1128/mbio.02289-23) (martinmartin2023aedesaegyptid7 pages 1-2, martinmartin2023aedesaegyptid7 pages 7-9, martinmartin2023aedesaegyptid7 pages 16-17).
8) Data highlights and key statistics
- Identity mapping: D7r2 = AGAP008282; salivary-gland gene under strong purifying selection (dN/dS ~0.08) (published Feb 2014; https://doi.org/10.1111/imb.12068) (arca2014positiveselectiondrives pages 2-4, arca2014positiveselectiondrives pages 4-5).
- Abundance: D7 proteins constitute ~5–20% of total salivary protein; salivary glands hold ~1–3 µg protein with ~50% delivered during blood feeding (published Jan 2006; https://doi.org/10.1074/jbc.M510359200) (calvo2006functionandevolution pages 5-6, calvo2006functionandevolution pages 1-1).
- Binding: Short-form D7s, including the D7r2/D7r3 clade, bind serotonin with low-nanomolar affinity and also bind norepinephrine/epinephrine and histamine, typically with ~1:1 stoichiometry (published Jan 2006; https://doi.org/10.1074/jbc.M510359200) (calvo2006functionandevolution pages 2-3, calvo2006functionandevolution pages 6-7, mans2007thecrystalstructure pages 1-1).
- Structure: Short-form D7 (exemplified by D7r4) adopts an eight-helix OBP-like fold stabilized by three disulfide bonds; binding-pocket residues govern amine specificity (published Dec 2007; https://doi.org/10.1074/jbc.M706410200) (mans2007thecrystalstructure pages 1-1).
Conclusions
Anopheles gambiae D7r2 (AGAP008282; UniProt Q9UB31) is a salivary-gland, short-form D7 protein belonging to the OBP/PBP-GOBP superfamily. It localizes to saliva and functions at the bite site as a high-affinity kratagonist of biogenic amines—particularly serotonin and catecholamines—thereby diminishing vasoconstriction, platelet aggregation, and inflammatory signaling to facilitate blood feeding. Structural and phylogenetic data support conserved OBP-like architecture and selective constraint on functional residues. Recent 2023 functional genetics in mosquitoes reinforce the central role of D7 proteins in feeding and pathogen interactions, while translational work highlights D7s as candidate exposure biomarkers and potential components of vector-targeted vaccines. URLs and dates are provided above for all cited sources (arca2014positiveselectiondrives pages 2-4, arca2014positiveselectiondrives pages 4-5, calvo2006functionandevolution pages 1-1, calvo2006functionandevolution pages 2-3, mans2007thecrystalstructure pages 1-1, arca2017anophelinesalivaryprotein pages 7-9, arca2017anophelinesalivaryprotein pages 9-10, alvarenga2010thefunctionand pages 1-2, jablonka2019functionalandstructural pages 9-10, martinmartin2023aedesaegyptid7 pages 1-2, martinmartin2023aedesaegyptid7 pages 7-9, martinmartin2023aedesaegyptid7 pages 16-17, guo2025unravelingthemolecular pages 21-21).
References
(arca2014positiveselectiondrives pages 2-4): B. Arcà, C. J. Struchiner, V. Pham, Gabriella Sferra, F. Lombardo, Marco Pombi, and José M. C. Ribeiro. Positive selection drives accelerated evolution of mosquito salivary genes associated with blood‐feeding. Insect Molecular Biology, 23:122-131, Feb 2014. URL: https://doi.org/10.1111/imb.12068, doi:10.1111/imb.12068. This article has 33 citations and is from a peer-reviewed journal.
(arca2014positiveselectiondrives pages 4-5): B. Arcà, C. J. Struchiner, V. Pham, Gabriella Sferra, F. Lombardo, Marco Pombi, and José M. C. Ribeiro. Positive selection drives accelerated evolution of mosquito salivary genes associated with blood‐feeding. Insect Molecular Biology, 23:122-131, Feb 2014. URL: https://doi.org/10.1111/imb.12068, doi:10.1111/imb.12068. This article has 33 citations and is from a peer-reviewed journal.
(calvo2006functionandevolution pages 1-1): Eric Calvo, Ben J. Mans, John F. Andersen, and José M.C. Ribeiro. Function and evolution of a mosquito salivary protein family*. Journal of Biological Chemistry, 281:1935-1942, Jan 2006. URL: https://doi.org/10.1074/jbc.m510359200, doi:10.1074/jbc.m510359200. This article has 292 citations and is from a domain leading peer-reviewed journal.
(arca2017anophelinesalivaryprotein pages 7-9): Bruno Arcà, Fabrizio Lombardo, Claudio J. Struchiner, and José M. C. Ribeiro. Anopheline salivary protein genes and gene families: an evolutionary overview after the whole genome sequence of sixteen anopheles species. BMC Genomics, Feb 2017. URL: https://doi.org/10.1186/s12864-017-3579-8, doi:10.1186/s12864-017-3579-8. This article has 86 citations and is from a peer-reviewed journal.
(arca2017anophelinesalivaryprotein pages 9-10): Bruno Arcà, Fabrizio Lombardo, Claudio J. Struchiner, and José M. C. Ribeiro. Anopheline salivary protein genes and gene families: an evolutionary overview after the whole genome sequence of sixteen anopheles species. BMC Genomics, Feb 2017. URL: https://doi.org/10.1186/s12864-017-3579-8, doi:10.1186/s12864-017-3579-8. This article has 86 citations and is from a peer-reviewed journal.
(alvarenga2010thefunctionand pages 1-2): Patricia H. Alvarenga, Ivo M. B. Francischetti, Eric Calvo, Anderson Sá-Nunes, José M. C. Ribeiro, and John F. Andersen. The function and three-dimensional structure of a thromboxane a2/cysteinyl leukotriene-binding protein from the saliva of a mosquito vector of the malaria parasite. PLoS Biology, 8:e1000547, Nov 2010. URL: https://doi.org/10.1371/journal.pbio.1000547, doi:10.1371/journal.pbio.1000547. This article has 72 citations and is from a highest quality peer-reviewed journal.
(jablonka2019functionalandstructural pages 9-10): Willy Jablonka, Il Hwan Kim, Patricia H. Alvarenga, Jesus G. Valenzuela, Jose´ M. C. Ribeiro, and John F. Andersen. Functional and structural similarities of d7 proteins in the independently-evolved salivary secretions of sand flies and mosquitoes. Scientific Reports, Mar 2019. URL: https://doi.org/10.1038/s41598-019-41848-0, doi:10.1038/s41598-019-41848-0. This article has 22 citations and is from a peer-reviewed journal.
(calvo2006functionandevolution pages 6-7): Eric Calvo, Ben J. Mans, John F. Andersen, and José M.C. Ribeiro. Function and evolution of a mosquito salivary protein family*. Journal of Biological Chemistry, 281:1935-1942, Jan 2006. URL: https://doi.org/10.1074/jbc.m510359200, doi:10.1074/jbc.m510359200. This article has 292 citations and is from a domain leading peer-reviewed journal.
(calvo2006functionandevolution pages 2-3): Eric Calvo, Ben J. Mans, John F. Andersen, and José M.C. Ribeiro. Function and evolution of a mosquito salivary protein family*. Journal of Biological Chemistry, 281:1935-1942, Jan 2006. URL: https://doi.org/10.1074/jbc.m510359200, doi:10.1074/jbc.m510359200. This article has 292 citations and is from a domain leading peer-reviewed journal.
(calvo2006functionandevolution pages 5-6): Eric Calvo, Ben J. Mans, John F. Andersen, and José M.C. Ribeiro. Function and evolution of a mosquito salivary protein family*. Journal of Biological Chemistry, 281:1935-1942, Jan 2006. URL: https://doi.org/10.1074/jbc.m510359200, doi:10.1074/jbc.m510359200. This article has 292 citations and is from a domain leading peer-reviewed journal.
(mans2007thecrystalstructure pages 1-1): Ben J. Mans, Eric Calvo, José M.C. Ribeiro, and John F. Andersen. The crystal structure of d7r4, a salivary biogenic amine-binding protein from the malaria mosquito anopheles gambiae*. Journal of Biological Chemistry, 282:36626-36633, Dec 2007. URL: https://doi.org/10.1074/jbc.m706410200, doi:10.1074/jbc.m706410200. This article has 94 citations and is from a domain leading peer-reviewed journal.
(martinmartin2023aedesaegyptid7 pages 1-2): Ines Martin-Martin, Bianca Burini Kojin, Azadeh Aryan, Adeline E. Williams, Alvaro Molina-Cruz, Paola Carolina Valenzuela-Leon, Gaurav Shrivastava, Karina Botello, Mahnaz Minai, Zach N. Adelman, and Eric Calvo. aedes aegypti d7 long salivary proteins modulate blood feeding and parasite infection. mBio, Dec 2023. URL: https://doi.org/10.1128/mbio.02289-23, doi:10.1128/mbio.02289-23. This article has 14 citations and is from a domain leading peer-reviewed journal.
(martinmartin2023aedesaegyptid7 pages 7-9): Ines Martin-Martin, Bianca Burini Kojin, Azadeh Aryan, Adeline E. Williams, Alvaro Molina-Cruz, Paola Carolina Valenzuela-Leon, Gaurav Shrivastava, Karina Botello, Mahnaz Minai, Zach N. Adelman, and Eric Calvo. aedes aegypti d7 long salivary proteins modulate blood feeding and parasite infection. mBio, Dec 2023. URL: https://doi.org/10.1128/mbio.02289-23, doi:10.1128/mbio.02289-23. This article has 14 citations and is from a domain leading peer-reviewed journal.
(martinmartin2023aedesaegyptid7 pages 16-17): Ines Martin-Martin, Bianca Burini Kojin, Azadeh Aryan, Adeline E. Williams, Alvaro Molina-Cruz, Paola Carolina Valenzuela-Leon, Gaurav Shrivastava, Karina Botello, Mahnaz Minai, Zach N. Adelman, and Eric Calvo. aedes aegypti d7 long salivary proteins modulate blood feeding and parasite infection. mBio, Dec 2023. URL: https://doi.org/10.1128/mbio.02289-23, doi:10.1128/mbio.02289-23. This article has 14 citations and is from a domain leading peer-reviewed journal.
(guo2025unravelingthemolecular pages 21-21): Jiayin Guo, Xiaoe He, Jianli Tao, Hui Sun, and Jing Yang. Unraveling the molecular mechanisms of mosquito salivary proteins: new frontiers in disease transmission and control. Biomolecules, 15:82, Jan 2025. URL: https://doi.org/10.3390/biom15010082, doi:10.3390/biom15010082. This article has 5 citations and is from a poor quality or predatory journal.
id: Q9UB31
gene_symbol: D7r2
product_type: PROTEIN
status: DRAFT
taxon:
id: NCBITaxon:7165
label: Anopheles gambiae
description: >-
D7r2 is a short-form salivary protein from female Anopheles gambiae mosquitoes that facilitates
blood feeding by binding and sequestering host biogenic amines (serotonin, histamine, and
norepinephrine). It functions as a "kratagonist" - capturing host signaling molecules with high
affinity to prevent their vasoconstrictive, platelet-aggregating, and inflammatory effects.
The protein is secreted into saliva during blood feeding. D7r2 belongs to the PBP/GOBP
(Pheromone/Odorant-Binding Protein) structural family but has evolved a distinct function
unrelated to olfaction.
existing_annotations:
# CC: Extracellular space (IBA)
- term:
id: GO:0005615
label: extracellular space
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
This annotation correctly reflects the subcellular localization of D7r2 as a secreted
salivary protein. The IBA annotation is based on phylogenetic inference from the PANTHER
family including D7r4 (Q7PNF2) which shares the same localization.
action: ACCEPT
reason: >-
D7r2 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q9UB31]. It is
released into the extracellular space (saliva) during blood feeding. The UniProt entry
confirms "SUBCELLULAR LOCATION: Secreted" (PMID:17913537) [UniProt Q9UB31]. The IBA
inference is appropriate as all D7 family members share this secreted localization pattern.
Deep research on the D7 family confirms "D7r1 is produced in adult female salivary glands
and secreted in saliva at the skin interface during probing/feeding"
[file:ANOGA/D7r1/D7r1-deep-research-falcon.md], which applies equally to D7r2.
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: "SUBCELLULAR LOCATION: Secreted"
- reference_id: PMID:17913537
supporting_text: >-
A proteomic and immunoproteomic analysis of anopheles and Aedes saliva allowed for
the identification of some antigens
# BP: Sensory perception of smell (IBA)
- term:
id: GO:0007608
label: sensory perception of smell
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
This annotation is INCORRECT. While the IBA inference is based on structural family membership
(PBP/GOBP-related proteins), D7r2 has no role in olfaction. The protein is expressed exclusively
in female salivary glands, not olfactory tissues, and functions in blood feeding facilitation,
not smell perception.
action: REMOVE
reason: >-
D7r2 belongs to the PBP/GOBP structural family (InterPro IPR006170), which includes olfactory
proteins in other contexts. However, the D7 subfamily has evolutionarily repurposed this fold
for binding biogenic amines in saliva to facilitate blood feeding, not for odorant detection.
D7r2 is expressed exclusively in adult female salivary glands [PMID:11841502, PMID:9990055],
not in olfactory tissues. It is not detected in male tissues or in embryo, larval, and pupal
stages [PMID:11841502]. The UniProt function annotation explicitly states D7r2 "Modulates
blood feeding of female mosquitoes on vertebrate species by binding and sequestering different
mediators involved in the host response" [UniProt Q9UB31] - with no mention of olfactory
function. Deep research confirms short-form D7s "predominantly bind biogenic amines
(serotonin/5-HT, histamine, epinephrine/norepinephrine)" not odorants
[file:ANOGA/D7r1/D7r1-deep-research-falcon.md]. The IBA inference from Drosophila odorant
binding proteins (FB:FBgn0011279, FB:FBgn0034468, etc.) is inappropriate as the function
has diverged in mosquito D7 proteins.
supported_by:
- reference_id: PMID:11841502
supporting_text: >-
Four genes expressed in the Anopheles gambiae adult female salivary glands
- reference_id: UniProt:Q9UB31
supporting_text: >-
Modulates blood feeding of female mosquitoes on vertebrate species by binding and
sequestering different mediators involved in the host response
# MF: Odorant binding (IEA)
- term:
id: GO:0005549
label: odorant binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
This annotation is based on structural family membership (PBP/GOBP family via InterPro
IPR006170) but does not reflect the actual function of D7r2. The protein binds biogenic
amines (serotonin, histamine, norepinephrine), not odorants, and has no role in olfaction.
action: MODIFY
reason: >-
D7r2 belongs to the PBP/GOBP structural family (InterPro IPR006170), which led to this
IEA annotation via GO_REF:0000002. However, the D7 proteins have evolutionarily repurposed
this fold for binding biogenic amines in saliva, not odorants in antennae. D7r2 is expressed
exclusively in female salivary glands [PMID:11841502, PMID:9990055], not olfactory tissues.
The actual molecular function is binding serotonin (GO:0051378), histamine (GO:0051381),
and norepinephrine (GO:0051380). UniProt confirms "Binds serotonin, noradrenaline, histamine
and adrenaline (PubMed:16301315)" [UniProt Q9UB31]. This is a clear case where structural
homology does not predict function. The GO:0005549 definition "Binding to an odorant, any
substance capable of stimulating the sense of smell" does not apply - serotonin, histamine,
and norepinephrine are not odorants. Deep research confirms D7 short forms "bind serotonin,
histamine, and catecholamines with high affinity" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
proposed_replacement_terms:
- id: GO:0051378
label: serotonin binding
- id: GO:0051381
label: histamine binding
- id: GO:0051380
label: norepinephrine binding
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: Binds serotonin, noradrenaline, histamine and adrenaline
- reference_id: PMID:16301315
supporting_text: >-
four of these five short D7 proteins and the D7 long form bind serotonin with high
affinity, as well as histamine and norepinephrine
# CC: Extracellular region (IEA)
- term:
id: GO:0005576
label: extracellular region
evidence_type: IEA
original_reference_id: GO_REF:0000044
review:
summary: >-
This annotation correctly reflects the subcellular localization of D7r2 as a secreted
salivary protein. It is appropriately broader than the more specific GO:0005615
(extracellular space) annotation.
action: ACCEPT
reason: >-
D7r2 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q9UB31]. The
UniProt entry confirms "SUBCELLULAR LOCATION: Secreted" based on PMID:17913537 [UniProt
Q9UB31]. It is released into the extracellular region (saliva) during blood feeding. This
IEA annotation from UniProt subcellular location vocabulary mapping (GO_REF:0000044) is
accurate. Deep research confirms D7 proteins are "secreted in saliva at the skin interface
during probing/feeding" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: "SUBCELLULAR LOCATION: Secreted"
# BP: Vasodilation (IEA)
- term:
id: GO:0042311
label: vasodilation
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is appropriate. D7r2 exhibits vasodilating activity by sequestering
host vasoconstrictors (serotonin, norepinephrine), thereby facilitating blood feeding.
action: ACCEPT
reason: >-
UniProt explicitly states D7r2 "Exhibits vasodilating activity (PubMed:16301315)" and
"Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction
(PubMed:16301315)" [UniProt Q9UB31]. By sequestering serotonin and norepinephrine (which
are vasoconstrictors), D7r2 effectively promotes vasodilation at the bite site. This IEA
annotation inferred from the UniProt keyword "Vasodilator" (KW-0840) via GO_REF:0000043
is accurate. Deep research confirms D7 kratagonist function "counteracts platelet
aggregation, vasoconstriction, and nociception during feeding"
[file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: >-
Exhibits vasodilating activity
- reference_id: PMID:16301315
supporting_text: >-
Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating,
and pain-inducing properties
# BP: Blood vessel diameter maintenance (IEA)
- term:
id: GO:0097746
label: blood vessel diameter maintenance
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is acceptable but less informative than the vasodilation annotation.
D7r2 modulates blood vessel diameter by promoting vasodilation through sequestration
of vasoconstrictive amines.
action: KEEP_AS_NON_CORE
reason: >-
D7r2 affects blood vessel diameter through its vasodilating activity - by sequestering
serotonin and norepinephrine (vasoconstrictors), it promotes vessel dilation at the bite
site. This IEA annotation from UniProt keyword "Vasoactive" (KW-0838) via GO_REF:0000043
is technically correct. However, this is a broader, less informative term than GO:0042311
(vasodilation), which better captures the specific mechanism. The primary function is
facilitating blood feeding through kratagonism, not general blood vessel maintenance.
Keeping as non-core since vasodilation (GO:0042311) is the more appropriate and specific
annotation.
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: >-
Exhibits vasodilating activity
# CC: Extracellular space (IDA)
- term:
id: GO:0005615
label: extracellular space
evidence_type: IDA
original_reference_id: PMID:17913537
review:
summary: >-
This annotation is experimentally supported by mass spectrometry identification of D7r2
in female saliva, demonstrating its localization in the extracellular space.
action: ACCEPT
reason: >-
PMID:17913537 (Orlandi-Pradines et al., 2007) performed proteomic analysis of Anopheles
gambiae saliva using mass spectrometry and identified D7r2 as a salivary protein in female
mosquitoes. The UniProt entry confirms "IDENTIFICATION BY MASS SPECTROMETRY, SUBCELLULAR
LOCATION, AND TISSUE SPECIFICITY" citing PMID:17913537 [UniProt Q9UB31]. The tissue
specificity annotation states "Female saliva (at protein level) (PubMed:17913537)"
[UniProt Q9UB31]. This IDA annotation with direct experimental evidence is correct and
more reliable than the IBA inference for the same term.
supported_by:
- reference_id: PMID:17913537
supporting_text: >-
A proteomic and immunoproteomic analysis of anopheles and Aedes saliva allowed for
the identification of some antigens
- reference_id: UniProt:Q9UB31
supporting_text: >-
Female saliva (at protein level)
# PROPOSED NEW ANNOTATIONS
- term:
id: GO:0051378
label: serotonin binding
evidence_type: IDA
original_reference_id: PMID:16301315
review:
summary: >-
D7r2 binds serotonin with high affinity as demonstrated by direct binding assays. This
is a core molecular function that should be annotated.
action: NEW
reason: >-
UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)"
[UniProt Q9UB31]. The protein has specific binding sites for serotonin (residues 31, 59, 118,
135, 138 based on homology to Q7PNF2) [UniProt Q9UB31]. PMID:16301315 demonstrated that "four
of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as
well as histamine and norepinephrine" using isothermal microcalorimetry and smooth muscle
bioassays [PMID:16301315]. This is the actual molecular function that enables kratagonism -
sequestering host serotonin to prevent vasoconstriction. GO:0051378 definition "Binding to
serotonin (5-hydroxytryptamine), a monoamine neurotransmitter" accurately describes this
function. Deep research confirms D7 short forms "bind serotonin, histamine, and catecholamines
with high affinity" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: Binds serotonin, noradrenaline, histamine and adrenaline
- reference_id: PMID:16301315
supporting_text: >-
four of these five short D7 proteins and the D7 long form bind serotonin with high
affinity, as well as histamine and norepinephrine
- term:
id: GO:0051381
label: histamine binding
evidence_type: IDA
original_reference_id: PMID:16301315
review:
summary: >-
D7r2 binds histamine with high affinity as demonstrated by direct binding assays. This
is a core molecular function that should be annotated.
action: NEW
reason: >-
UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)"
[UniProt Q9UB31]. The protein has specific binding sites for histamine (residues 118, 135,
138 based on homology to Q7PNF2) [UniProt Q9UB31]. PMID:16301315 demonstrated that short D7
proteins bind "serotonin with high affinity, as well as histamine and norepinephrine" using
isothermal microcalorimetry and smooth muscle bioassays [PMID:16301315]. This is the actual
molecular function that enables sequestration of host histamine to prevent inflammation
and pruritus. GO:0051381 definition "Binding to histamine, a physiologically active amine"
accurately describes this function. Deep research confirms short-form D7s bind "biogenic
amines (serotonin/5-HT, histamine, epinephrine/norepinephrine)"
[file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: Binds serotonin, noradrenaline, histamine and adrenaline
- reference_id: PMID:16301315
supporting_text: >-
four of these five short D7 proteins and the D7 long form bind serotonin with high
affinity, as well as histamine and norepinephrine
- term:
id: GO:0051380
label: norepinephrine binding
evidence_type: IDA
original_reference_id: PMID:16301315
review:
summary: >-
D7r2 binds norepinephrine (noradrenaline) with high affinity as demonstrated by direct
binding assays. This is a core molecular function that should be annotated.
action: NEW
reason: >-
UniProt confirms "Binds serotonin, noradrenaline, histamine and adrenaline (PubMed:16301315)"
[UniProt Q9UB31]. The protein has specific binding sites for noradrenaline (residues 31, 46,
135, 138 based on homology to Q7PNF2) [UniProt Q9UB31]. UniProt also states D7r2 "Inhibits
histamine-, serotonin- and noradrenaline-induced smooth muscle contraction (PubMed:16301315)"
[UniProt Q9UB31]. PMID:16301315 demonstrated that short D7 proteins bind "serotonin with
high affinity, as well as histamine and norepinephrine" [PMID:16301315]. This molecular
function enables sequestration of host norepinephrine to prevent vasoconstriction.
GO:0051380 definition "Binding to norepinephrine... a hormone secreted by the adrenal
medulla and a neurotransmitter" accurately describes this function.
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: Binds serotonin, noradrenaline, histamine and adrenaline
- reference_id: PMID:16301315
supporting_text: >-
four of these five short D7 proteins and the D7 long form bind serotonin with high
affinity, as well as histamine and norepinephrine
- term:
id: GO:1900047
label: negative regulation of hemostasis
evidence_type: IDA
original_reference_id: PMID:16301315
review:
summary: >-
D7r2 negatively regulates host hemostasis by sequestering serotonin (which promotes
platelet aggregation) and other biogenic amines. This is a core biological process annotation.
action: NEW
reason: >-
By sequestering serotonin (which promotes platelet aggregation), histamine, and norepinephrine,
D7r2 negatively regulates the host hemostatic response during blood feeding. PMID:16301315
explicitly states "Scavenging of host amines would antagonize their vasoconstrictor,
platelet-aggregating, and pain-inducing properties" [PMID:16301315]. Deep research confirms
biogenic amine scavenging "counteracts platelet aggregation, vasoconstriction, and nociception
during feeding" [file:ANOGA/D7r1/D7r1-deep-research-falcon.md]. GO:1900047 definition "Any
process that stops, prevents or reduces the frequency, rate or extent of hemostasis" accurately
captures this function. This is a more accurate BP annotation than vague terms. Note that the
D7r1 homolog hamadarin also has anticoagulant activity via contact pathway inhibition,
suggesting this family broadly inhibits hemostasis [file:ANOGA/D7r1/D7r1-deep-research-falcon.md].
supported_by:
- reference_id: PMID:16301315
supporting_text: >-
Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating,
and pain-inducing properties
- reference_id: file:ANOGA/D7r1/D7r1-deep-research-falcon.md
supporting_text: >-
D7 proteins act as 'kratagonists' - scavenging host small-molecule mediators (amines,
leukotrienes, TXA2) at the bite site to blunt vasoconstriction, platelet aggregation,
pain/itch and inflammation, thereby facilitating blood feeding
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000033
title: Annotation inferences using phylogenetic trees
findings: []
- id: GO_REF:0000043
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
findings: []
- id: GO_REF:0000044
title: >-
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary
mapping, accompanied by conservative changes to GO terms applied by UniProt
findings: []
- id: PMID:16301315
title: Function and evolution of a mosquito salivary protein family
findings:
- statement: D7 short proteins bind serotonin, histamine and norepinephrine with high affinity
supporting_text: >-
four of these five short D7 proteins and the D7 long form bind serotonin with high
affinity, as well as histamine and norepinephrine
- statement: Scavenging host amines antagonizes vasoconstriction and platelet aggregation
supporting_text: >-
Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating,
and pain-inducing properties
- statement: D7 family evolved similar function to tick and bug lipocalins
supporting_text: >-
counteracting biogenic amines is of strong adaptive value in the convergent evolution
of arthropods to hematophagy
- id: PMID:17913537
title: >-
Antibody response against saliva antigens of Anopheles gambiae and Aedes aegypti in
travellers in tropical Africa
findings:
- statement: D7r2 identified by mass spectrometry in female A. gambiae saliva
supporting_text: >-
A proteomic and immunoproteomic analysis of anopheles and Aedes saliva allowed for
the identification of some antigens that were recognized by most of the exposed individuals
- id: PMID:11841502
title: >-
A cluster of four D7-related genes is expressed in the salivary glands of the African
malaria vector Anopheles gambiae
findings:
- statement: D7r genes are expressed in adult female salivary glands
supporting_text: >-
Four genes expressed in the Anopheles gambiae adult female salivary glands and similar
in sequence to the Aedes aegypti D7 gene were identified
- id: PMID:9990055
title: >-
Trapping cDNAs encoding secreted proteins from the salivary glands of the malaria
vector Anopheles gambiae
findings:
- statement: D7-related genes were identified in A. gambiae salivary glands
supporting_text: >-
Fragments showing a high degree of similarity to D7 and apyrase, two salivary
gland-specific genes previously found in Aedes aegypti, were identified
- id: UniProt:Q9UB31
title: UniProt entry for D7R2_ANOGA
findings:
- statement: D7r2 modulates blood feeding by binding host mediators
supporting_text: >-
Modulates blood feeding of female mosquitoes on vertebrate species by binding and
sequestering different mediators involved in the host response
- statement: Binds serotonin, noradrenaline, histamine and adrenaline
supporting_text: >-
Binds serotonin, noradrenaline, histamine and adrenaline
- statement: Inhibits amine-induced smooth muscle contraction
supporting_text: >-
Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction
- statement: Exhibits vasodilating activity
supporting_text: >-
Exhibits vasodilating activity
- statement: Expressed in female salivary gland
supporting_text: >-
Female salivary gland (PubMed:9990055)
- statement: Protein is secreted
supporting_text: "SUBCELLULAR LOCATION: Secreted"
- id: file:ANOGA/D7r1/D7r1-deep-research-falcon.md
title: Deep research review of D7r1 function and evolution (applies to D7 family)
findings:
- statement: D7 proteins function as kratagonists that scavenge host signaling molecules
supporting_text: >-
D7 proteins are among the most abundant mosquito salivary proteins and function
as kratagonists - high-affinity scavengers of host small-molecule inflammatory
and hemostatic mediators
- statement: Short-form D7s bind biogenic amines
supporting_text: >-
Short-form D7s (including D7r1) predominantly bind biogenic amines (serotonin/5-HT,
histamine, epinephrine/norepinephrine)
- statement: D7r proteins are secreted in saliva during feeding
supporting_text: >-
D7r1 is produced in adult female salivary glands and secreted in saliva at the
skin interface during probing/feeding
core_functions:
- description: >-
D7r2 functions as a kratagonist by binding and sequestering host biogenic amines (serotonin,
histamine, and norepinephrine) during blood feeding, thereby preventing vasoconstriction,
platelet aggregation, and inflammation at the feeding site.
molecular_function:
id: GO:0051378
label: serotonin binding
directly_involved_in:
- id: GO:1900047
label: negative regulation of hemostasis
- id: GO:0042311
label: vasodilation
locations:
- id: GO:0005615
label: extracellular space
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: >-
Modulates blood feeding of female mosquitoes on vertebrate species by binding and
sequestering different mediators involved in the host response
- reference_id: PMID:16301315
supporting_text: >-
four of these five short D7 proteins and the D7 long form bind serotonin with high
affinity, as well as histamine and norepinephrine
- description: >-
D7r2 also binds histamine to prevent host inflammatory and pruritic responses during
blood feeding.
molecular_function:
id: GO:0051381
label: histamine binding
directly_involved_in:
- id: GO:1900047
label: negative regulation of hemostasis
- id: GO:0042311
label: vasodilation
locations:
- id: GO:0005615
label: extracellular space
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: Binds serotonin, noradrenaline, histamine and adrenaline
- description: >-
D7r2 binds norepinephrine (noradrenaline) to prevent host vasoconstrictive responses
during blood feeding.
molecular_function:
id: GO:0051380
label: norepinephrine binding
directly_involved_in:
- id: GO:1900047
label: negative regulation of hemostasis
- id: GO:0042311
label: vasodilation
locations:
- id: GO:0005615
label: extracellular space
supported_by:
- reference_id: UniProt:Q9UB31
supporting_text: >-
Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction
suggested_questions:
- question: >-
What are the specific binding affinities (Kd values) of D7r2 for serotonin, histamine,
and norepinephrine, and how do they compare to D7r1 and other short-form D7 proteins?
experts:
- Calvo E
- Ribeiro JM
- Andersen JF
- question: >-
Is there functional redundancy among the D7r1-D7r4 short-form proteins, or do they
have distinct substrate preferences or tissue localization patterns?
experts:
- Calvo E
- Mans BJ
suggested_experiments:
- hypothesis: >-
D7r2 knockout mosquitoes will have reduced blood feeding efficiency due to host hemostatic
and inflammatory responses
description: >-
Generate D7r2 knockout A. gambiae using CRISPR and measure blood meal size, feeding time,
and feeding success rate compared to wild-type controls. Compare to D7r1 knockouts to
assess redundancy.
experiment_type: Gene knockout and feeding assay
- hypothesis: >-
D7r2 has distinct binding site residues compared to D7r4 that confer substrate specificity
description: >-
Solve the crystal structure of D7r2 in complex with serotonin, histamine, and norepinephrine
to identify binding site residues and compare to the published D7r4 structure (Mans et al., 2007)
experiment_type: Structural biology