D7r2

UniProt ID: Q9UB31
Organism: Anopheles gambiae
Review Status: DRAFT
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Gene 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 Review

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

Core Functions

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.

Supporting Evidence:
  • UniProt:Q9UB31
    Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response
  • 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

D7r2 also binds histamine to prevent host inflammatory and pruritic responses during blood feeding.

Supporting Evidence:
  • UniProt:Q9UB31
    Binds serotonin, noradrenaline, histamine and adrenaline

D7r2 binds norepinephrine (noradrenaline) to prevent host vasoconstrictive responses during blood feeding.

Supporting Evidence:
  • UniProt:Q9UB31
    Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction

References

Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Function and evolution of a mosquito salivary protein family
  • D7 short proteins bind serotonin, histamine and norepinephrine with high affinity
    "four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine"
  • Scavenging host amines antagonizes vasoconstriction and platelet aggregation
    "Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating, and pain-inducing properties"
  • D7 family evolved similar function to tick and bug lipocalins
    "counteracting biogenic amines is of strong adaptive value in the convergent evolution of arthropods to hematophagy"
Antibody response against saliva antigens of Anopheles gambiae and Aedes aegypti in travellers in tropical Africa
  • D7r2 identified by mass spectrometry in female A. gambiae saliva
    "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"
A cluster of four D7-related genes is expressed in the salivary glands of the African malaria vector Anopheles gambiae
  • D7r genes are expressed in adult female salivary glands
    "Four genes expressed in the Anopheles gambiae adult female salivary glands and similar in sequence to the Aedes aegypti D7 gene were identified"
Trapping cDNAs encoding secreted proteins from the salivary glands of the malaria vector Anopheles gambiae
  • D7-related genes were identified in A. gambiae salivary glands
    "Fragments showing a high degree of similarity to D7 and apyrase, two salivary gland-specific genes previously found in Aedes aegypti, were identified"
UniProt:Q9UB31
UniProt entry for D7R2_ANOGA
  • D7r2 modulates blood feeding by binding host mediators
    "Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response"
  • Binds serotonin, noradrenaline, histamine and adrenaline
    "Binds serotonin, noradrenaline, histamine and adrenaline"
  • Inhibits amine-induced smooth muscle contraction
    "Inhibits histamine-, serotonin- and noradrenaline-induced smooth muscle contraction"
  • Exhibits vasodilating activity
    "Exhibits vasodilating activity"
  • Expressed in female salivary gland
    "Female salivary gland (PubMed:9990055)"
  • Protein is secreted
    "SUBCELLULAR LOCATION: Secreted"
file:ANOGA/D7r1/D7r1-deep-research-falcon.md
Deep research review of D7r1 function and evolution (applies to D7 family)
  • D7 proteins function as kratagonists that scavenge host signaling molecules
    "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"
  • Short-form D7s bind biogenic amines
    "Short-form D7s (including D7r1) predominantly bind biogenic amines (serotonin/5-HT, histamine, epinephrine/norepinephrine)"
  • D7r proteins are secreted in saliva during feeding
    "D7r1 is produced in adult female salivary glands and secreted in saliva at the skin interface during probing/feeding"

Suggested Questions for Experts

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

Suggested Experiments

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

📚 Additional Documentation

Deep Research Falcon

(D7r2-deep-research-falcon.md)

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gene_id: D7r2
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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)
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Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

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.

Target Gene/Protein Identity (from UniProt):

  • 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 Information: 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. .
  • Key Domains: PBP/GOBP. (IPR006170); PBP_GOBP_sf. (IPR036728); PBP_GOBP (PF01395)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "D7r2" matches the protein description above
  2. Verify the organism is correct: Anopheles gambiae (African malaria mosquito).
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

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

Research Target:

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.

Output

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.

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

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.

Target Gene/Protein Identity (from UniProt):

  • 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 Information: 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. .
  • Key Domains: PBP/GOBP. (IPR006170); PBP_GOBP_sf. (IPR036728); PBP_GOBP (PF01395)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "D7r2" matches the protein description above
  2. Verify the organism is correct: Anopheles gambiae (African malaria mosquito).
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

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

Research Target:

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

  1. (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.

  2. (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.

  3. (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.

  4. (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.

  5. (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.

  6. (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.

  7. (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.

  8. (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.

  9. (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.

  10. (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.

  11. (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.

  12. (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.

  13. (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.

  14. (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.

  15. (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.

Citations

  1. mans2007thecrystalstructure pages 1-1
  2. arca2014positiveselectiondrives pages 2-4
  3. guo2025unravelingthemolecular pages 21-21
  4. arca2014positiveselectiondrives pages 4-5
  5. calvo2006functionandevolution pages 1-1
  6. arca2017anophelinesalivaryprotein pages 7-9
  7. arca2017anophelinesalivaryprotein pages 9-10
  8. alvarenga2010thefunctionand pages 1-2
  9. jablonka2019functionalandstructural pages 9-10
  10. calvo2006functionandevolution pages 6-7
  11. calvo2006functionandevolution pages 2-3
  12. calvo2006functionandevolution pages 5-6
  13. https://doi.org/10.1111/imb.12068
  14. https://doi.org/10.1074/jbc.M510359200;
  15. https://doi.org/10.1186/s12864-017-3579-8
  16. https://doi.org/10.1371/journal.pbio.1000547
  17. https://doi.org/10.1074/jbc.M510359200
  18. https://doi.org/10.1074/jbc.M706410200
  19. https://doi.org/10.1371/journal.pbio.1000547;
  20. https://doi.org/10.1038/s41598-019-41848-0
  21. https://doi.org/10.1111/imb.12068;
  22. https://doi.org/10.1128/mbio.02289-23
  23. https://doi.org/10.1038/s41467-024-52502-3
  24. https://doi.org/10.3390/biom15010082
  25. https://doi.org/10.1074/jbc.M706410200;
  26. https://doi.org/10.1111/imb.12068,
  27. https://doi.org/10.1074/jbc.m510359200,
  28. https://doi.org/10.1186/s12864-017-3579-8,
  29. https://doi.org/10.1371/journal.pbio.1000547,
  30. https://doi.org/10.1038/s41598-019-41848-0,
  31. https://doi.org/10.1074/jbc.m706410200,
  32. https://doi.org/10.1128/mbio.02289-23,
  33. https://doi.org/10.3390/biom15010082,

📄 View Raw YAML

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