D7L1 (AngaD7L1) is a long-form D7 salivary protein from female Anopheles gambiae mosquitoes that facilitates blood feeding by binding and sequestering host eicosanoids. Unlike short-form D7 proteins which bind biogenic amines (serotonin, histamine), D7L1 specifically binds leukotriene C4 and thromboxane A2 (tested using the stable analog U-46619). The protein functions as a "kratagonist" - capturing host signaling molecules with high affinity to prevent their vasoconstrictive, platelet-aggregating, and inflammatory effects. D7L1 inhibits U-46619- induced platelet aggregation and exhibits vasodilating activity. It is secreted into saliva during blood feeding and 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 D7L1 as a secreted salivary protein. The IBA annotation is based on phylogenetic inference (GO_REF:0000033) and is consistent with experimental data showing D7 proteins are secreted into saliva.
Reason: D7L1 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q7PJ76]. It is released into the extracellular space (saliva) during blood feeding. The UniProt entry confirms "SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}" [UniProt Q7PJ76]. This is an appropriate CC annotation consistent with the protein's function as a secreted kratagonist that sequesters host mediators at the feeding site.
Supporting Evidence:
UniProt:Q7PJ76
SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}.
|
|
GO:0007608
sensory perception of smell
|
IBA
GO_REF:0000033 |
REMOVE |
Summary: This annotation is INCORRECT for D7L1. While the IBA annotation is based on phylogenetic inference from the PBP/GOBP family, D7L1 has evolved a completely different function. The protein is expressed in salivary glands, not olfactory tissues, and functions in blood feeding by sequestering host eicosanoids, not in olfaction.
Reason: D7L1 belongs to the PBP/GOBP structural family (InterPro IPR006170), which led to this IBA annotation based on phylogenetic inference. However, the D7 long-form proteins have evolutionarily repurposed this fold for binding eicosanoids (leukotrienes, thromboxane) in saliva, not odorants in antennae. UniProt explicitly describes D7L1's function: "Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response" and "Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2" [UniProt Q7PJ76, PMID:35460690]. The protein is expressed exclusively in female salivary glands, not olfactory tissues. GO:0007608 definition "The series of events required to receive an olfactory stimulus" does not apply - D7L1 has no role in olfaction. This is a clear case where structural homology (driving the IBA annotation) does not predict function.
Supporting Evidence:
UniProt:Q7PJ76
Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response
UniProt:Q7PJ76
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
PMID:35460690
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
|
|
GO:0035821
modulation of process of another organism
|
IEA
GO_REF:0000108 |
ACCEPT |
Summary: This annotation accurately describes D7L1's function. The protein modulates host hemostatic and inflammatory responses during blood feeding by sequestering eicosanoids (leukotriene C4 and thromboxane A2). This is a correct BP annotation for the cross-species effect.
Reason: D7L1 clearly modulates processes in the vertebrate host. Per UniProt, it "Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response" [UniProt Q7PJ76]. The GO:0035821 definition "A process in which an organism effects a change in a biological process in another organism" accurately captures this function. The annotation was inferred via GO_REF:0000108 from the toxin activity annotation, but the logic is sound - kratagonistic binding of host eicosanoids does modulate host processes. Specifically, D7L1 inhibits U-46619-induced platelet aggregation and exhibits vasodilating activity [PMID:35460690].
Supporting Evidence:
UniProt:Q7PJ76
Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response
PMID:35460690
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
|
|
GO:0005549
odorant binding
|
IEA
GO_REF:0000002 |
MODIFY |
Summary: This annotation is INCORRECT based on structural family membership (PBP/GOBP family via InterPro IPR006170) but does not reflect the actual function of D7L1. The protein binds eicosanoids (leukotriene C4, thromboxane A2), not odorants, and has no role in olfaction.
Reason: D7L1 belongs to the PBP/GOBP structural family (InterPro IPR006170), which led to this IEA annotation. However, the D7 long-form proteins have evolutionarily repurposed this fold for binding eicosanoids in saliva, not odorants in antennae. D7L1 is expressed exclusively in female salivary glands, not olfactory tissues. The actual molecular function is icosanoid binding (GO:0050542) - specifically binding leukotriene C4 and thromboxane A2 analog U-46619 [PMID:35460690]. IMPORTANTLY: D7L1 does NOT bind biogenic amines (serotonin, histamine) - this is the key difference from short-form D7 proteins like D7r1. The GO:0005549 definition "Binding to an odorant, any substance capable of stimulating the sense of smell" does not apply - leukotriene C4 and thromboxane A2 are not odorants. UniProt explicitly states "Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2" [PMID:35460690].
Proposed replacements:
icosanoid binding
Supporting Evidence:
UniProt:Q7PJ76
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
PMID:35460690
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
|
|
GO:0005576
extracellular region
|
IEA
GO_REF:0000044 |
ACCEPT |
Summary: This annotation correctly reflects the subcellular localization of D7L1 as a secreted salivary protein. This is broader than GO:0005615 (extracellular space) but still accurate.
Reason: D7L1 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q7PJ76]. It is released into the extracellular region (saliva) during blood feeding. The UniProt entry confirms "SUBCELLULAR LOCATION: Secreted" [UniProt Q7PJ76]. This is an appropriate CC annotation. Having both GO:0005576 (extracellular region) and GO:0005615 (extracellular space) is acceptable as they represent different levels of granularity.
Supporting Evidence:
UniProt:Q7PJ76
SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}.
|
|
GO:0042311
vasodilation
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: This annotation is supported by experimental evidence. D7L1 exhibits vasodilating activity by sequestering vasoconstrictor eicosanoids (thromboxane A2), thereby preventing vasoconstriction at the feeding site.
Reason: UniProt explicitly states "Exhibits vasodilating activity (PubMed:35460690)" [UniProt Q7PJ76]. By binding and sequestering thromboxane A2 (tested using analog U-46619), D7L1 prevents this potent vasoconstrictor from acting on host blood vessels. The net effect is vasodilation at the feeding site, facilitating blood meal acquisition. GO:0042311 definition "The increase in the internal diameter of blood vessels" accurately describes the consequence of D7L1's kratagonist activity.
Supporting Evidence:
UniProt:Q7PJ76
Exhibits vasodilating activity (PubMed:35460690).
|
|
GO:0090729
toxin activity
|
IEA
GO_REF:0000043 |
MARK AS OVER ANNOTATED |
Summary: This annotation is an OVER-ANNOTATION. D7L1 does not meet the GO definition of toxin activity, which requires "initiating pathogenesis (leading to an abnormal, generally detrimental state)". D7L1 transiently modulates host physiology without causing disease or tissue damage.
Reason: The GO:0090729 definition states: "Interacting selectively with one or more biological molecules in another (target) organism, initiating pathogenesis (leading to an abnormal, generally detrimental state) in the target organism." D7L1 does NOT meet this definition because: (1) It does not initiate pathogenesis - it facilitates feeding, not disease; (2) It does not cause tissue damage - it transiently sequesters host eicosanoids; (3) The effect is reversible and temporary; (4) The host returns to normal state after feeding. The UniProt keywords "Hemostasis impairing toxin" and "Platelet aggregation inhibiting toxin" that led to this IEA annotation via GO_REF:0000043 are technically inaccurate - anti-hemostatic activity is not equivalent to toxin activity. The kratagonist mechanism (sequestering signaling molecules) is fundamentally different from true toxins that cause pathological damage. Better annotations would be icosanoid binding (GO:0050542) for MF, and negative regulation of hemostasis (GO:1900047) for BP.
Supporting Evidence:
UniProt:Q7PJ76
Modulates blood feeding of female mosquitoes on vertebrate species by binding and sequestering different mediators involved in the host response
|
|
GO:0097746
blood vessel diameter maintenance
|
IEA
GO_REF:0000043 |
KEEP AS NON CORE |
Summary: This annotation is technically accurate but vague. D7L1 does affect blood vessel diameter by promoting vasodilation through sequestration of the vasoconstrictor thromboxane A2. However, GO:0042311 (vasodilation) is more specific and already annotated.
Reason: D7L1 affects blood vessel diameter by sequestering thromboxane A2 and preventing vasoconstriction, resulting in vasodilation [PMID:35460690, UniProt Q7PJ76]. GO:0097746 definition "Any process that modulates the diameter of blood vessels" is accurate but less specific than GO:0042311 (vasodilation) which is already annotated. This annotation can be kept as non-core since it provides additional context about the protein's role in vascular regulation, but GO:0042311 better captures the specific function.
Supporting Evidence:
UniProt:Q7PJ76
Exhibits vasodilating activity (PubMed:35460690).
|
|
GO:0050542
icosanoid binding
|
IDA
PMID:35460690 Novel salivary antihemostatic activities of long-form D7 pro... |
NEW |
Summary: D7L1 binds icosanoids (leukotriene C4 and thromboxane A2) with high affinity as demonstrated by direct binding assays. This is the core molecular function that should be annotated.
Reason: UniProt confirms "Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)" [UniProt Q7PJ76]. Both leukotriene C4 and thromboxane A2 are icosanoids (C20 polyunsaturated fatty acid derivatives). GO:0050542 definition "Binding to icosanoids, any C20 polyunsaturated fatty acids or their derivatives, including the leukotrienes and the prostanoids" accurately describes D7L1's molecular function. This is the actual binding activity that enables the kratagonist mechanism - sequestering host icosanoids to prevent their vasoconstrictive and platelet-aggregating effects. IMPORTANT: D7L1 specifically binds eicosanoids, NOT biogenic amines like serotonin or histamine (which are bound by short-form D7 proteins like D7r1).
Supporting Evidence:
UniProt:Q7PJ76
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
PMID:35460690
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
|
|
GO:1900047
negative regulation of hemostasis
|
IDA
PMID:35460690 Novel salivary antihemostatic activities of long-form D7 pro... |
NEW |
Summary: D7L1 inhibits platelet aggregation by sequestering thromboxane A2, which represents negative regulation of hemostasis. This is a core biological process annotation.
Reason: UniProt states "Inhibits agonist-induced platelet aggregation (PubMed:35460690)" [UniProt Q7PJ76]. By sequestering thromboxane A2 (which promotes platelet aggregation), D7L1 negatively regulates the host hemostatic response. 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 inferring from "toxin activity". The inhibition of U-46619-induced platelet aggregation is the key experimental evidence demonstrating this function [PMID:35460690].
Supporting Evidence:
PMID:35460690
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
|
|
GO:0090331
negative regulation of platelet aggregation
|
IDA
PMID:35460690 Novel salivary antihemostatic activities of long-form D7 pro... |
NEW |
Summary: D7L1 inhibits U-46619-induced platelet aggregation by sequestering thromboxane A2. This is a more specific annotation than negative regulation of hemostasis.
Reason: UniProt explicitly states "Inhibits agonist-induced platelet aggregation (PubMed:35460690)" [UniProt Q7PJ76]. The specific agonist is U-46619, a stable thromboxane A2 analog. By binding and sequestering thromboxane A2, D7L1 prevents it from activating platelet aggregation. GO:0090331 definition "Any process that decreases the rate, frequency or extent of platelet aggregation" accurately describes this function. This provides a more specific BP annotation than GO:1900047 (negative regulation of hemostasis).
Supporting Evidence:
PMID:35460690
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
PMID:35460690
AngaD7L1 had a dose-dependent inhibitory effect on platelet aggregation
|
|
GO:0045906
negative regulation of vasoconstriction
|
IDA
PMID:35460690 Novel salivary antihemostatic activities of long-form D7 pro... |
NEW |
Summary: D7L1 inhibits vasoconstriction by sequestering thromboxane A2 (tested using U-46619). This annotation captures the mechanism behind the vasodilating activity.
Reason: UniProt states "Exhibits vasodilating activity (PubMed:35460690)" [UniProt Q7PJ76]. The mechanism is through binding and sequestering thromboxane A2, preventing it from inducing vasoconstriction. GO:0045906 definition "Any process that stops, prevents, or reduces the frequency, rate or extent of vasoconstriction" accurately describes this function. This provides mechanistic context to the GO:0042311 (vasodilation) annotation.
Supporting Evidence:
UniProt:Q7PJ76
Exhibits vasodilating activity (PubMed:35460690).
PMID:35460690
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
|
Q: What is the binding affinity (Kd) of D7L1 for leukotriene C4 vs thromboxane A2 (U-46619), and does it show preference for one over the other?
Suggested experts: Calvo E, Ribeiro JM
Q: Are there functional differences between D7L1 and other long-form D7 proteins (D7L2, D7L3) in terms of ligand binding specificity?
Suggested experts: Calvo E, Mans BJ
Experiment: Generate D7L1 knockout A. gambiae using CRISPR and measure blood meal size, feeding time, and feeding success rate compared to wild-type controls
Hypothesis: D7L1 knockout mosquitoes will have reduced blood feeding efficiency due to host hemostatic responses
Type: Gene knockout and feeding assay
Experiment: Perform competitive binding assays and structural analysis (crystallography or cryo-EM) with D7L1 bound to LTC4, U-46619, or both to determine binding site organization
Hypothesis: D7L1 binding to leukotriene C4 and thromboxane A2 occurs at distinct binding pockets within the two-domain structure of this long-form D7 protein
Type: Structural biology and binding assays
provider: falcon
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organism: ANOGA
gene_id: D7L1
gene_symbol: D7L1
uniprot_accession: Q7PJ76
protein_description: 'RecName: Full=Long form salivary protein D7L1 {ECO:0000305};
Short=AngaD7L1 {ECO:0000303|PubMed:35460690}; Flags: Precursor;'
gene_info: Name=D7L1 {ECO:0000305}; ORFNames=AgaP_AGAP008278 {ECO:0000312|EMBL:EAA43866.1};
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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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 'D7L1' 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 D7L1 (gene ID: D7L1, UniProt: Q7PJ76) 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 'D7L1' 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 D7L1 (gene ID: D7L1, UniProt: Q7PJ76) 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.
Research plan and verification
- Identity: D7L1 (AGAP008278) encodes the long-form salivary protein AngaD7L1 from Anopheles gambiae; UniProt Q7PJ76 lists it as a secreted D7 long-form salivary protein in the odorant-binding protein-related PBP/GOBP family (IPR006170; IPR036728; PF01395). The symbol D7L1 is used in other species (e.g., Aedes aegypti), so all functional claims below are restricted to An. gambiae unless explicitly noted as comparative. Where An. gambiae–specific data are lacking, family-level inference is stated transparently (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9).
Key concepts and definitions
- D7 family: D7 proteins are highly abundant mosquito salivary proteins related to insect odorant-binding proteins that evolved to bind and sequester (“kratagonize”) host hemostatic and inflammatory mediators at the bite site. Long-form D7 proteins (~27–30 kDa) contain two OBP-like domains; short forms (~15–20 kDa) contain one. Long forms typically show domain specialization: N-terminal domains bind cysteinyl leukotrienes/eicosanoids; C-terminal domains bind biogenic amines such as histamine, serotonin, norepinephrine, and epinephrine (family-level evidence) (https://doi.org/10.1128/mbio.02289-23, Dec 2023; https://doi.org/10.1038/s41467-020-16665-z, Jun 2020) (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2020adpbindingby pages 1-2).
- Mechanism (kratagonism): By high-affinity 1:1 binding of small-molecule agonists (biogenic amines, leukotrienes, thromboxane A2, and in some species ADP/ATP), D7 proteins blunt vasoconstriction, platelet activation/aggregation, vascular permeability changes, and leukocyte recruitment, thereby facilitating blood feeding (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2020adpbindingby pages 1-2).
Protein identity, domains, and predicted localization of AngaD7L1 (Q7PJ76)
- Identity and domains: AngaD7L1 is annotated as a D7 long-form salivary protein with PBP/GOBP domains (IPR006170; IPR036728; PF01395), consistent with an OBP-like two-domain fold typical of long-form D7s (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9).
- Localization and secretion: D7 long-form proteins are female salivary-gland proteins secreted into saliva and reingested during feeding; in Aedes aegypti these proteins localize to distal lateral lobes and are abundant in saliva and bloodmeals. By conservation across mosquito genera, AngaD7L1 is expected to be secreted from An. gambiae salivary glands into the host skin during probing/feeding (https://doi.org/10.1128/mbio.02289-23, Dec 2023) (martinmartin2023aedesaegyptid7 pages 1-2, martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7).
Function and pathway context (evidence and inference)
- Primary biochemical role (inferred for AngaD7L1): As a D7 long-form, AngaD7L1 likely binds small pro-hemostatic and pro-inflammatory mediators at the bite site, most plausibly cysteinyl leukotrienes (eicosanoids) via its N-terminal domain and biogenic amines via its C-terminal domain, thereby reducing platelet aggregation, vasoconstriction, and leukocyte recruitment. This inference follows conserved D7 long-form biochemistry demonstrated directly in Aedes and Culex (https://doi.org/10.1128/mbio.02289-23; https://doi.org/10.1038/s41467-020-16665-z) (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2020adpbindingby pages 1-2).
- Pathways affected: D7 long forms modulate host hemostasis (platelet activation pathways including thromboxane A2 and ADP, collagen-mediated aggregation), vascular tone (adrenergic signaling via norepinephrine/epinephrine), and inflammation (histamine signaling; leukotrienes from 5-lipoxygenase pathway). These effects shorten probing time and improve blood-meal acquisition; they can also shape pathogen transmission contexts (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2020adpbindingby pages 1-2).
Recent developments and latest research (2023–2024 priority)
- Aedes aegypti D7 long-form knockouts (mBio, Dec 2023): CRISPR/Cas9 knockout lines for D7L1 and D7L2 showed prolonged probing times on mouse (4.7× for D7L1-KO; 4.1× for D7L2-KO) and chicken (3.0×; 2.6×) compared with wild type. Importantly, probing-time defects were rescued on leukotriene-deficient (Alox5−/−) mice, providing in vivo evidence that D7 long forms counteract leukotriene-mediated inflammation. D7 proteins were detected in ingested blood, indicating reingestion. Parasite outcomes: oocyst loads of Plasmodium gallinaceum were reduced by 53.5% (D7L1-KO) and 66.3% (D7L2-KO) despite similar blood-meal sizes, suggesting that D7s influence the intramidgut milieu and early parasite development (https://doi.org/10.1128/mbio.02289-23, Dec 2023) (martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2023aedesaegyptid7 pages 9-11).
- Salivary immunomodulation context (Science Immunology, Aug 2024): Independent of D7 specifically, a 34-kDa Aedes salivary factor (Nest1) binds the human CD47 checkpoint to suppress phagocytosis and enhance arboviral infection in human skin explants, underscoring that mosquito saliva contains multiple targeted immunomodulators acting alongside D7 proteins to modify local immunity and infectivity (https://doi.org/10.1126/sciimmunol.adk9872, Aug 2024) (martinmartin2020adpbindingby pages 1-2).
Comparative perspective: long-form D7 diversity across genera
- Culex quinquefasciatus (Nature Communications, Jun 2020): Two long-form D7s show divergent ligand specificities: CxD7L2 binds biogenic amines and eicosanoids, while CxD7L1 uniquely binds nucleotides (ADP/ATP) via an inter-domain pocket; a 1.97 Å crystal structure with ADP revealed a distinct binding mode. Functionally, these proteins inhibit platelet aggregation and enhance mammalian blood feeding, particularly via ADP sequestration in the case of CxD7L1 (https://doi.org/10.1038/s41467-020-16665-z, Jun 2020) (martinmartin2020adpbindingby pages 1-2, martinmartin2020adpbindingby pages 13-14).
- General D7 family roles (mBio 2023 overview): Long forms are widely conserved in mosquito saliva with biochemical and structural studies supporting binding to leukotrienes, thromboxane A2, and biogenic amines, and with demonstrated importance for probing efficiency and pathogen interactions in vivo (https://doi.org/10.1128/mbio.02289-23, Dec 2023) (martinmartin2023aedesaegyptid7 pages 14-16).
What is specifically known vs. inferred for AngaD7L1 (An. gambiae; Q7PJ76)
- Known: AngaD7L1 is a D7 long-form salivary protein (OBP-related PBP/GOBP family) expressed in the salivary glands of Anopheles gambiae. D7 genes are clustered and highly expressed in the salivary glands across mosquito species. Salivary D7s act as major antigens in multiple genera (comparative evidence) (martinmartin2020adpbindingby pages 13-14).
- Not yet demonstrated specifically for AngaD7L1 in the retrieved 2023–2024 literature: direct ligand-binding specificity (e.g., Kd values for cysteinyl leukotrienes or amines), high-resolution structure, AngaD7L1-targeted knockout or silencing phenotypes, and platelet/hemostasis functional assays. Given the conservation of the D7 long-form fold and biochemical activities, AngaD7L1 is most likely a secreted kratagonist of biogenic amines and eicosanoids; however, nucleotide binding like CxD7L1 cannot be assumed without direct evidence (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9).
Experimental evidence and statistics supporting D7 long-form functions (comparative)
- KO phenotypes (Ae. aegypti): Probing time increased 4.7× (D7L1-KO) and 4.1× (D7L2-KO) on mice; 3.0× and 2.6× on chickens. Rescue on Alox5−/− mice implicates leukotriene scavenging. Oocyst loads reduced by 53.5% (D7L1-KO) and 66.3% (D7L2-KO). Protein absence validated by ELISA, mass spectrometry, immunofluorescence; saliva proteomes otherwise largely preserved (https://doi.org/10.1128/mbio.02289-23, Dec 2023) (martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2023aedesaegyptid7 pages 9-11).
- Structural/biophysical (Culex): CxD7L1–ADP crystal structure at 1.97 Å with an inter-domain nucleotide-binding pocket; biochemical assays showed high-affinity nucleotide binding; ex vivo and in vivo platelet/hemostasis inhibition demonstrated (https://doi.org/10.1038/s41467-020-16665-z, Jun 2020) (martinmartin2020adpbindingby pages 1-2, martinmartin2020adpbindingby pages 13-14).
Current applications and real-world implementations
- Vector biology and transmission: D7 long-form activity directly improves probing and feeding efficiency and can modulate parasite acquisition (reduced oocysts in KO lines), highlighting D7s as targets for transmission-blocking strategies and biomarkers of exposure (https://doi.org/10.1128/mbio.02289-23, Dec 2023) (martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2023aedesaegyptid7 pages 9-11).
- Therapeutic inspiration: The Culex D7 nucleotide-binding function illustrates how salivary D7s can target critical nodes in human hemostasis (ADP-mediated platelet activation), suggesting potential templates for antiplatelet agents and for designing inhibitors or vaccines that neutralize salivary kratagonism at the bite site (https://doi.org/10.1038/s41467-020-16665-z, Jun 2020) (martinmartin2020adpbindingby pages 1-2).
- Immunomodulation context for bite-site interventions: Although not D7-specific, recent work shows mosquito salivary proteins can target human immune checkpoints (CD47), reinforcing the concept that bite-site immunomodulation is a viable intervention point complementary to D7-focused approaches (https://doi.org/10.1126/sciimmunol.adk9872, Aug 2024) (martinmartin2020adpbindingby pages 1-2).
Expert opinions and analysis (authoritative sources)
- The mBio 2023 study authors conclude that long-form D7 proteins function as in vivo leukotriene scavengers that shorten probing times and that reingested D7s may shape midgut conditions affecting parasite development; they advocate further experiments (e.g., supplementation with recombinant D7, anti-D7 antibodies) to dissect mechanisms, underscoring D7s as biologically pivotal salivary factors (https://doi.org/10.1128/mbio.02289-23, Dec 2023) (martinmartin2023aedesaegyptid7 pages 1-2, martinmartin2023aedesaegyptid7 pages 9-11).
- The Nature Communications 2020 study argues that D7 functional diversification (e.g., ADP binding) evolved to optimize feeding on mammalian hosts where ADP is central to platelet aggregation, highlighting adaptive specialization of D7s across mosquito lineages and supporting careful species-specific characterization for AngaD7L1 (https://doi.org/10.1038/s41467-020-16665-z, Jun 2020) (martinmartin2020adpbindingby pages 1-2).
Limitations and data gaps for AngaD7L1 (Q7PJ76)
- Gene symbol ambiguity: “D7L1” is used in multiple mosquito species; we restrict interpretation to Anopheles gambiae and do not transfer species-specific binding idiosyncrasies (e.g., Culex ADP binding) without direct evidence (martinmartin2020adpbindingby pages 13-14).
- Missing AngaD7L1-specific data: No 2023–2024 primary reports located in the retrieved evidence with direct biochemistry (ligand binding constants), structural data, or KO/silencing phenotypes for AGAP008278. Functional roles are therefore inferred from conserved D7 long-form biology and comparative studies in Aedes and Culex (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9).
Targeted hypotheses and experimental next steps for AngaD7L1
- Biochemistry: Test binding to cysteinyl leukotrienes (LTC4, LTD4, LTE4) and biogenic amines (histamine, serotonin, norepinephrine) via ITC/fluorescence and define domain usage; screen nucleotides (ADP/ATP) to rule in/out Culex-like specialization.
- Structure: Determine AngaD7L1 crystal/NMR structure ± ligands to identify pocket architecture versus Aedes/Culex templates.
- Genetics and physiology: Generate AGAP008278 KO/silencing lines in An. gambiae; measure probing time, feeding success, and hemostasis parameters; assess effects on Plasmodium acquisition (oocyst counts) and transmission.
- Localization: Confirm salivary gland lobe localization and secretion via immunofluorescence and targeted proteomics of saliva.
Concise evidence summary table
| Species / Protein | Gene ID / Name | Form | Primary ligands | Mechanism (domain usage) | Experimental evidence | Reported phenotypes | Year | Source (DOI URL) |
|---|---|---:|---|---|---|---|---:|---|
| Aedes aegypti D7L1 / D7L2 | D7L1 (AAEL006424), D7L2 (AAEL006417) | Long (~27–30 kDa) | Biogenic amines (serotonin, histamine, NE), cysteinyl leukotrienes (eicosanoids) | N‑terminal domain binds cysteinyl leukotrienes; C‑terminal binds biogenic amines (kratagonism) | CRISPR/Cas9 KO lines; ELISA, MS, immunofluorescence; behavioral probing assays; parasite infection (oocyst counts) (martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2023aedesaegyptid7 pages 9-11) | Probing time ↑ (mouse: D7L1-KO 4.7×, D7L2-KO 4.1×; chicken: 3.0× and 2.6×); oocyst load ↓ (D7L1-KO 53.5%, D7L2-KO 66.3%) (martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7) | 2023 | https://doi.org/10.1128/mbio.02289-23 (martinmartin2023aedesaegyptid7 pages 1-2) |
| Culex quinquefasciatus CxD7L1 / CxD7L2 | CxD7L1, CxD7L2 | Long | CxD7L2: biogenic amines & eicosanoids; CxD7L1: ADP/ATP (nucleotides) | CxD7L1 uses an inter‑domain nucleotide pocket (distinct interdomain binding vs. domain‑local binding in other D7s) | Recombinant proteins; binding assays; crystal structure CxD7L1–ADP (1.97 Å); platelet aggregation and in vivo hemostasis assays (martinmartin2020adpbindingby pages 1-2, martinmartin2020adpbindingby pages 13-14) | Inhibits platelet aggregation/hemostasis; ADP binding enhances mammalian blood feeding (martinmartin2020adpbindingby pages 1-2) | 2020 | https://doi.org/10.1038/s41467-020-16665-z (martinmartin2020adpbindingby pages 1-2) |
| General D7 family context (comparative) | Multiple D7 genes across mosquito genera | Long and short forms (long ≈ two domains; short ≈ one domain) | Biogenic amines, leukotrienes/eicosanoids, TXA2; species‑dependent nucleotide binding reported | Long‑form two‑domain architecture with domain specialization; act as kratagonists scavenging host hemostatic/inflammatory mediators | Structural studies, sialotranscriptomics/proteomics, ligand binding assays across species; broad functional inference from comparative work (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2020adpbindingby pages 1-2) | Conserved role facilitating blood feeding by reducing probing time and modulating inflammation; can influence pathogen acquisition/transmission (various experimental reports) (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2023aedesaegyptid7 pages 4-7) | 2015–2023 | Key refs: https://doi.org/10.1128/mbio.02289-23; https://doi.org/10.1038/s41467-020-16665-z (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2020adpbindingby pages 1-2) |
| Inference — Anopheles gambiae AngaD7L1 (Q7PJ76) | D7L1 / AGAP008278 (UniProt Q7PJ76) | Predicted long‑form (salivary D7) | Inferred: likely binds biogenic amines and/or eicosanoids; nucleotide binding not demonstrated for this protein | Annotated as PBP/GOBP (OBP‑related) family; domain signatures IPR006170 / IPR036728 / PF01395 → predicted secreted salivary kratagonist | Evidence limited to annotation/family‑level conservation and sialotranscriptome/proteome contexts; no AngaD7L1‑specific binding, structure, or KO studies retrieved (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9) | Experimental phenotypes for AngaD7L1 unconfirmed; by analogy to other D7 long proteins, expect effects on probing/hemostasis and possible impacts on pathogen acquisition pending direct assays (binding, structure, KO) (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9) | Annotation current ≤2024; experimental data lacking | UniProt: https://www.uniprot.org/uniprot/Q7PJ76; comparative studies: https://doi.org/10.1128/mbio.02289-23; https://doi.org/10.1038/s41467-020-16665-z (martinmartin2020adpbindingby pages 13-14, martinmartin2023aedesaegyptid7 pages 7-9) |
Table: Concise comparison of experimental evidence for D7 long‑form salivary proteins (Aedes, Culex) and an inference row for Anopheles gambiae AngaD7L1 (Q7PJ76), summarizing ligands, mechanisms, assays, quantified phenotypes, and key sources to guide targeted functional validation.
Conclusions for AngaD7L1 (Anopheles gambiae)
- Identity and domains verify D7 long-form membership, predicting a secreted salivary OBP-like two-domain protein (PBP/GOBP family). Based on conserved D7 long-form mechanisms, AngaD7L1 is most likely a kratagonist that scavenges leukotrienes and biogenic amines to counter host hemostasis and inflammation and to improve feeding efficiency. Comparative 2023–2024 studies in Aedes demonstrate in vivo leukotriene dependence for probing-time rescue and substantial effects on parasite oocyst formation; Culex studies reveal lineage-specific innovation (ADP binding) that should be tested but not assumed for Anopheles. Direct AngaD7L1 biochemical and genetic validation remains a key gap and opportunity for near-term research (martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2020adpbindingby pages 1-2).
Cited sources with URLs and dates
- Martin-Martin I, et al. Aedes aegypti D7 long salivary proteins modulate blood feeding and parasite infection. mBio. Published Dec 2023. URL: https://doi.org/10.1128/mbio.02289-23 (martinmartin2023aedesaegyptid7 pages 1-2, martinmartin2023aedesaegyptid7 pages 2-4, martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2023aedesaegyptid7 pages 4-7, martinmartin2023aedesaegyptid7 pages 9-11).
- Martin-Martin I, et al. ADP binding by the Culex quinquefasciatus mosquito D7 salivary protein enhances blood feeding on mammals. Nature Communications. Published Jun 2020. URL: https://doi.org/10.1038/s41467-020-16665-z (martinmartin2020adpbindingby pages 1-2, martinmartin2020adpbindingby pages 13-14).
- Marin-Lopez A, et al. The human CD47 checkpoint is targeted by an immunosuppressive Aedes aegypti salivary factor to enhance arboviral skin infectivity. Science Immunology. Published Aug 2024. URL: https://doi.org/10.1126/sciimmunol.adk9872 (martinmartin2020adpbindingby pages 1-2).
- Additional background on D7 family distribution and salivary context drawn from the mBio 2023 study’s comparative discussion (martinmartin2023aedesaegyptid7 pages 14-16, martinmartin2023aedesaegyptid7 pages 4-7).
References
(martinmartin2020adpbindingby pages 13-14): Ines Martin-Martin, Andrew Paige, Paola Carolina Valenzuela Leon, Apostolos G. Gittis, Olivia Kern, Brian Bonilla, Andrezza Campos Chagas, Sundar Ganesan, Leticia Barion Smith, David N. Garboczi, and Eric Calvo. Adp binding by the culex quinquefasciatus mosquito d7 salivary protein enhances blood feeding on mammals. Nature Communications, Jun 2020. URL: https://doi.org/10.1038/s41467-020-16665-z, doi:10.1038/s41467-020-16665-z. This article has 36 citations and is from a highest quality 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 14-16): 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.
(martinmartin2020adpbindingby pages 1-2): Ines Martin-Martin, Andrew Paige, Paola Carolina Valenzuela Leon, Apostolos G. Gittis, Olivia Kern, Brian Bonilla, Andrezza Campos Chagas, Sundar Ganesan, Leticia Barion Smith, David N. Garboczi, and Eric Calvo. Adp binding by the culex quinquefasciatus mosquito d7 salivary protein enhances blood feeding on mammals. Nature Communications, Jun 2020. URL: https://doi.org/10.1038/s41467-020-16665-z, doi:10.1038/s41467-020-16665-z. This article has 36 citations and is from a highest quality 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 2-4): 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 4-7): 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 9-11): 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.
id: Q7PJ76
gene_symbol: D7L1
product_type: PROTEIN
status: DRAFT
taxon:
id: NCBITaxon:7165
label: Anopheles gambiae
description: >-
D7L1 (AngaD7L1) is a long-form D7 salivary protein from female Anopheles gambiae mosquitoes
that facilitates blood feeding by binding and sequestering host eicosanoids. Unlike short-form
D7 proteins which bind biogenic amines (serotonin, histamine), D7L1 specifically binds
leukotriene C4 and thromboxane A2 (tested using the stable analog U-46619). The protein
functions as a "kratagonist" - capturing host signaling molecules with high affinity to prevent
their vasoconstrictive, platelet-aggregating, and inflammatory effects. D7L1 inhibits U-46619-
induced platelet aggregation and exhibits vasodilating activity. It is secreted into saliva
during blood feeding and belongs to the PBP/GOBP (Pheromone/Odorant-Binding Protein) structural
family but has evolved a distinct function unrelated to olfaction.
existing_annotations:
- 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 D7L1 as a secreted
salivary protein. The IBA annotation is based on phylogenetic inference (GO_REF:0000033)
and is consistent with experimental data showing D7 proteins are secreted into saliva.
action: ACCEPT
reason: >-
D7L1 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q7PJ76]. It is
released into the extracellular space (saliva) during blood feeding. The UniProt entry
confirms "SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}" [UniProt Q7PJ76].
This is an appropriate CC annotation consistent with the protein's function as a secreted
kratagonist that sequesters host mediators at the feeding site.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: "SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}."
- term:
id: GO:0007608
label: sensory perception of smell
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
This annotation is INCORRECT for D7L1. While the IBA annotation is based on phylogenetic
inference from the PBP/GOBP family, D7L1 has evolved a completely different function. The
protein is expressed in salivary glands, not olfactory tissues, and functions in blood
feeding by sequestering host eicosanoids, not in olfaction.
action: REMOVE
reason: >-
D7L1 belongs to the PBP/GOBP structural family (InterPro IPR006170), which led to this IBA
annotation based on phylogenetic inference. However, the D7 long-form proteins have
evolutionarily repurposed this fold for binding eicosanoids (leukotrienes, thromboxane) in
saliva, not odorants in antennae. UniProt explicitly describes D7L1's function: "Modulates
blood feeding of female mosquitoes on vertebrate species by binding and sequestering
different mediators involved in the host response" and "Binds leukotriene C4 and U-46619,
a stable analog of thromboxane A2" [UniProt Q7PJ76, PMID:35460690]. The protein is expressed
exclusively in female salivary glands, not olfactory tissues. GO:0007608 definition
"The series of events required to receive an olfactory stimulus" does not apply - D7L1 has
no role in olfaction. This is a clear case where structural homology (driving the IBA
annotation) does not predict function.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: >-
Modulates blood feeding of female mosquitoes on vertebrate species by binding and
sequestering different mediators involved in the host response
- reference_id: UniProt:Q7PJ76
supporting_text: >-
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
- reference_id: PMID:35460690
supporting_text: >-
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
- term:
id: GO:0035821
label: modulation of process of another organism
evidence_type: IEA
original_reference_id: GO_REF:0000108
review:
summary: >-
This annotation accurately describes D7L1's function. The protein modulates host hemostatic
and inflammatory responses during blood feeding by sequestering eicosanoids (leukotriene C4
and thromboxane A2). This is a correct BP annotation for the cross-species effect.
action: ACCEPT
reason: >-
D7L1 clearly modulates processes in the vertebrate host. Per UniProt, it "Modulates blood
feeding of female mosquitoes on vertebrate species by binding and sequestering different
mediators involved in the host response" [UniProt Q7PJ76]. The GO:0035821 definition
"A process in which an organism effects a change in a biological process in another organism"
accurately captures this function. The annotation was inferred via GO_REF:0000108 from the
toxin activity annotation, but the logic is sound - kratagonistic binding of host eicosanoids
does modulate host processes. Specifically, D7L1 inhibits U-46619-induced platelet aggregation
and exhibits vasodilating activity [PMID:35460690].
supported_by:
- reference_id: UniProt:Q7PJ76
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:35460690
supporting_text: >-
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
- term:
id: GO:0005549
label: odorant binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
This annotation is INCORRECT based on structural family membership (PBP/GOBP family via
InterPro IPR006170) but does not reflect the actual function of D7L1. The protein binds
eicosanoids (leukotriene C4, thromboxane A2), not odorants, and has no role in olfaction.
action: MODIFY
reason: >-
D7L1 belongs to the PBP/GOBP structural family (InterPro IPR006170), which led to this
IEA annotation. However, the D7 long-form proteins have evolutionarily repurposed this
fold for binding eicosanoids in saliva, not odorants in antennae. D7L1 is expressed
exclusively in female salivary glands, not olfactory tissues. The actual molecular function
is icosanoid binding (GO:0050542) - specifically binding leukotriene C4 and thromboxane A2
analog U-46619 [PMID:35460690]. IMPORTANTLY: D7L1 does NOT bind biogenic amines (serotonin,
histamine) - this is the key difference from short-form D7 proteins like D7r1. The GO:0005549
definition "Binding to an odorant, any substance capable of stimulating the sense of smell"
does not apply - leukotriene C4 and thromboxane A2 are not odorants. UniProt explicitly
states "Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2" [PMID:35460690].
proposed_replacement_terms:
- id: GO:0050542
label: icosanoid binding
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: >-
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
- reference_id: PMID:35460690
supporting_text: >-
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
- 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 D7L1 as a secreted
salivary protein. This is broader than GO:0005615 (extracellular space) but still accurate.
action: ACCEPT
reason: >-
D7L1 is a secreted protein with a signal peptide (residues 1-21) [UniProt Q7PJ76]. It is
released into the extracellular region (saliva) during blood feeding. The UniProt entry
confirms "SUBCELLULAR LOCATION: Secreted" [UniProt Q7PJ76]. This is an appropriate CC
annotation. Having both GO:0005576 (extracellular region) and GO:0005615 (extracellular
space) is acceptable as they represent different levels of granularity.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: "SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}."
- term:
id: GO:0042311
label: vasodilation
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is supported by experimental evidence. D7L1 exhibits vasodilating activity
by sequestering vasoconstrictor eicosanoids (thromboxane A2), thereby preventing
vasoconstriction at the feeding site.
action: ACCEPT
reason: >-
UniProt explicitly states "Exhibits vasodilating activity (PubMed:35460690)" [UniProt Q7PJ76].
By binding and sequestering thromboxane A2 (tested using analog U-46619), D7L1 prevents
this potent vasoconstrictor from acting on host blood vessels. The net effect is vasodilation
at the feeding site, facilitating blood meal acquisition. GO:0042311 definition "The
increase in the internal diameter of blood vessels" accurately describes the consequence
of D7L1's kratagonist activity.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: "Exhibits vasodilating activity (PubMed:35460690)."
- term:
id: GO:0090729
label: toxin activity
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is an OVER-ANNOTATION. D7L1 does not meet the GO definition of toxin
activity, which requires "initiating pathogenesis (leading to an abnormal, generally
detrimental state)". D7L1 transiently modulates host physiology without causing disease
or tissue damage.
action: MARK_AS_OVER_ANNOTATED
reason: >-
The GO:0090729 definition states: "Interacting selectively with one or more biological
molecules in another (target) organism, initiating pathogenesis (leading to an abnormal,
generally detrimental state) in the target organism." D7L1 does NOT meet this definition
because: (1) It does not initiate pathogenesis - it facilitates feeding, not disease;
(2) It does not cause tissue damage - it transiently sequesters host eicosanoids; (3) The
effect is reversible and temporary; (4) The host returns to normal state after feeding.
The UniProt keywords "Hemostasis impairing toxin" and "Platelet aggregation inhibiting toxin"
that led to this IEA annotation via GO_REF:0000043 are technically inaccurate - anti-hemostatic
activity is not equivalent to toxin activity. The kratagonist mechanism (sequestering
signaling molecules) is fundamentally different from true toxins that cause pathological
damage. Better annotations would be icosanoid binding (GO:0050542) for MF, and negative
regulation of hemostasis (GO:1900047) for BP.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: >-
Modulates blood feeding of female mosquitoes on vertebrate species by binding and
sequestering different mediators involved in the host response
- term:
id: GO:0097746
label: blood vessel diameter maintenance
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is technically accurate but vague. D7L1 does affect blood vessel diameter
by promoting vasodilation through sequestration of the vasoconstrictor thromboxane A2.
However, GO:0042311 (vasodilation) is more specific and already annotated.
action: KEEP_AS_NON_CORE
reason: >-
D7L1 affects blood vessel diameter by sequestering thromboxane A2 and preventing
vasoconstriction, resulting in vasodilation [PMID:35460690, UniProt Q7PJ76]. GO:0097746
definition "Any process that modulates the diameter of blood vessels" is accurate but less
specific than GO:0042311 (vasodilation) which is already annotated. This annotation can be
kept as non-core since it provides additional context about the protein's role in vascular
regulation, but GO:0042311 better captures the specific function.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: "Exhibits vasodilating activity (PubMed:35460690)."
# PROPOSED NEW ANNOTATIONS
- term:
id: GO:0050542
label: icosanoid binding
evidence_type: IDA
original_reference_id: PMID:35460690
review:
summary: >-
D7L1 binds icosanoids (leukotriene C4 and thromboxane A2) with high affinity as demonstrated
by direct binding assays. This is the core molecular function that should be annotated.
action: NEW
reason: >-
UniProt confirms "Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2
(PubMed:35460690)" [UniProt Q7PJ76]. Both leukotriene C4 and thromboxane A2 are icosanoids
(C20 polyunsaturated fatty acid derivatives). GO:0050542 definition "Binding to icosanoids,
any C20 polyunsaturated fatty acids or their derivatives, including the leukotrienes and
the prostanoids" accurately describes D7L1's molecular function. This is the actual binding
activity that enables the kratagonist mechanism - sequestering host icosanoids to prevent
their vasoconstrictive and platelet-aggregating effects. IMPORTANT: D7L1 specifically binds
eicosanoids, NOT biogenic amines like serotonin or histamine (which are bound by short-form
D7 proteins like D7r1).
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: >-
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
- reference_id: PMID:35460690
supporting_text: >-
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
- term:
id: GO:1900047
label: negative regulation of hemostasis
evidence_type: IDA
original_reference_id: PMID:35460690
review:
summary: >-
D7L1 inhibits platelet aggregation by sequestering thromboxane A2, which represents negative
regulation of hemostasis. This is a core biological process annotation.
action: NEW
reason: >-
UniProt states "Inhibits agonist-induced platelet aggregation (PubMed:35460690)" [UniProt Q7PJ76].
By sequestering thromboxane A2 (which promotes platelet aggregation), D7L1 negatively
regulates the host hemostatic response. 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 inferring from "toxin activity".
The inhibition of U-46619-induced platelet aggregation is the key experimental evidence
demonstrating this function [PMID:35460690].
supported_by:
- reference_id: PMID:35460690
supporting_text: >-
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
- term:
id: GO:0090331
label: negative regulation of platelet aggregation
evidence_type: IDA
original_reference_id: PMID:35460690
review:
summary: >-
D7L1 inhibits U-46619-induced platelet aggregation by sequestering thromboxane A2. This
is a more specific annotation than negative regulation of hemostasis.
action: NEW
reason: >-
UniProt explicitly states "Inhibits agonist-induced platelet aggregation (PubMed:35460690)"
[UniProt Q7PJ76]. The specific agonist is U-46619, a stable thromboxane A2 analog. By
binding and sequestering thromboxane A2, D7L1 prevents it from activating platelet
aggregation. GO:0090331 definition "Any process that decreases the rate, frequency or
extent of platelet aggregation" accurately describes this function. This provides a
more specific BP annotation than GO:1900047 (negative regulation of hemostasis).
supported_by:
- reference_id: PMID:35460690
supporting_text: >-
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
- reference_id: PMID:35460690
supporting_text: >-
AngaD7L1 had a dose-dependent inhibitory effect on platelet aggregation
- term:
id: GO:0045906
label: negative regulation of vasoconstriction
evidence_type: IDA
original_reference_id: PMID:35460690
review:
summary: >-
D7L1 inhibits vasoconstriction by sequestering thromboxane A2 (tested using U-46619).
This annotation captures the mechanism behind the vasodilating activity.
action: NEW
reason: >-
UniProt states "Exhibits vasodilating activity (PubMed:35460690)" [UniProt Q7PJ76]. The
mechanism is through binding and sequestering thromboxane A2, preventing it from inducing
vasoconstriction. GO:0045906 definition "Any process that stops, prevents, or reduces the
frequency, rate or extent of vasoconstriction" accurately describes this function. This
provides mechanistic context to the GO:0042311 (vasodilation) annotation.
supported_by:
- reference_id: UniProt:Q7PJ76
supporting_text: "Exhibits vasodilating activity (PubMed:35460690)."
- reference_id: PMID:35460690
supporting_text: >-
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
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: GO_REF:0000108
title: Automatic assignment of GO terms using logical inference, based on inter-ontology links
findings: []
- id: PMID:35460690
title: >-
Novel salivary antihemostatic activities of long-form D7 proteins from the malaria
vector Anopheles gambiae facilitate hematophagy
findings:
- statement: D7L1 (AngaD7L1) binds leukotriene C4 and thromboxane A2 analog U-46619
supporting_text: >-
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
- statement: D7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction
supporting_text: >-
functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation
and vasoconstriction
- statement: D7L1 is a vasodilator that inhibits vasoconstriction to U-46619
supporting_text: >-
A. gambiae salivary D7L1 and D7L3 proteins are vasodilators
- statement: D7L1 had dose-dependent inhibitory effect on platelet aggregation
supporting_text: >-
When platelet aggregation was initiated with U-46619, AngaD7L1 had a dose-dependent
inhibitory effect on platelet aggregation
- id: UniProt:Q7PJ76
title: UniProt entry for D7L1_ANOGA (Long form salivary protein D7L1)
findings:
- statement: D7L1 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: D7L1 binds leukotriene C4 and thromboxane A2 analog
supporting_text: >-
Binds leukotriene C4 and U-46619, a stable analog of thromboxane A2 (PubMed:35460690)
- statement: D7L1 inhibits platelet aggregation
supporting_text: >-
Inhibits agonist- induced platelet aggregation (PubMed:35460690)
- statement: D7L1 exhibits vasodilating activity
supporting_text: "Exhibits vasodilating activity (PubMed:35460690)."
- statement: D7L1 is secreted
supporting_text: "SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P18153}."
core_functions:
- description: >-
D7L1 functions as a kratagonist by binding and sequestering host icosanoids (leukotriene C4
and thromboxane A2) during blood feeding, thereby preventing vasoconstriction, platelet
aggregation, and inflammation at the feeding site. Unlike short-form D7 proteins which bind
biogenic amines, D7L1 specifically targets eicosanoid signaling molecules.
molecular_function:
id: GO:0050542
label: icosanoid binding
directly_involved_in:
- id: GO:1900047
label: negative regulation of hemostasis
- id: GO:0090331
label: negative regulation of platelet aggregation
- id: GO:0045906
label: negative regulation of vasoconstriction
- id: GO:0035821
label: modulation of process of another organism
locations:
- id: GO:0005576
label: extracellular region
- id: GO:0005615
label: extracellular space
supported_by:
- reference_id: UniProt:Q7PJ76
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:35460690
supporting_text: >-
We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619
suggested_questions:
- question: >-
What is the binding affinity (Kd) of D7L1 for leukotriene C4 vs thromboxane A2 (U-46619),
and does it show preference for one over the other?
experts:
- Calvo E
- Ribeiro JM
- question: >-
Are there functional differences between D7L1 and other long-form D7 proteins (D7L2, D7L3)
in terms of ligand binding specificity?
experts:
- Calvo E
- Mans BJ
suggested_experiments:
- hypothesis: >-
D7L1 knockout mosquitoes will have reduced blood feeding efficiency due to host hemostatic
responses
description: >-
Generate D7L1 knockout A. gambiae using CRISPR and measure blood meal size, feeding time,
and feeding success rate compared to wild-type controls
experiment_type: Gene knockout and feeding assay
- hypothesis: >-
D7L1 binding to leukotriene C4 and thromboxane A2 occurs at distinct binding pockets
within the two-domain structure of this long-form D7 protein
description: >-
Perform competitive binding assays and structural analysis (crystallography or cryo-EM)
with D7L1 bound to LTC4, U-46619, or both to determine binding site organization
experiment_type: Structural biology and binding assays