TEP2 (Thioester-containing protein 2) is a secreted complement-like protein belonging to the alpha-2-macroglobulin/thioester-containing protein family in the African malaria mosquito Anopheles gambiae. TEP2 contains a conserved thioester motif (GCGEQ) that enables covalent attachment to pathogen surfaces, functioning as a predicted opsonin similar to the well-characterized TEP1. The protein is encoded by gene AGAP008366 located in a TEP gene cluster on chromosome arm 3R (29A-30E), near TEP15. While TEP1 has been extensively studied for its role in anti-Plasmodium immunity, TEP2 remains less characterized but is predicted to function similarly based on conserved domain architecture. TEP2 expression is induced ~9-fold in mosGILT-null mosquitoes, indicating responsiveness to immune pathway perturbation. The protein is expected to be secreted into the hemolymph where it circulates until deployment on pathogen surfaces.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0002376
immune system process
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: This IEA annotation is derived from the UniProt keyword "Immunity" (KW-0391) through automated mapping. TEP2 is a thioester-containing protein belonging to the TEP family which functions in insect innate immunity. The protein contains an intact thioester motif and is part of the complement-like immune pathway in A. gambiae (Christophides et al., 2002). Expression is significantly induced (~9-fold) in mosGILT-null mosquitoes, demonstrating responsiveness to immune pathway perturbation (Arora et al., 2024).
Reason: TEP2 is a member of the thioester-containing protein family which plays essential roles in insect innate immunity. The annotation to "immune system process" is technically correct and appropriate for this complement-like protein, although it is a broad term. The induction of TEP2 in immune-perturbed mosquitoes and its TEP family membership strongly support this annotation.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
TEP2 is a distinct An. gambiae TEP gene in a multi-gene cluster on chromosome arm 3R (29A-30E). TEP2 lies very close to TEP15, with other TEPs (TEP12-14) located farther within the same region. TEP2 is annotated with a present thioester (TE) motif, consistent with complement-like opsonin function
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001), indicating strong inducibility under immune/reproductive pathway perturbation
|
|
GO:0004866
endopeptidase inhibitor activity
|
IEA
GO_REF:0000002 |
REMOVE |
Summary: This annotation is derived from InterPro domain mapping (IPR001599 Alpha-2- macroglobulin and IPR002890 MG2 domain) which are shared with protease inhibitors like alpha-2-macroglobulin. However, TEP2 is a thioester-containing protein that belongs to the complement-like branch of this family, not the protease inhibitor branch. Similar to the well-characterized TEP1 in A. gambiae, TEP2 is predicted to function as an opsonin that covalently tags pathogen surfaces via its reactive thioester bond, not as a protease inhibitor (Shokal and Eleftherianos, 2017). There is no experimental evidence that TEP2 acts as an endopeptidase inhibitor.
Reason: TEP2 is a thioester-containing protein that functions as a predicted complement-like opsonin in the insect innate immune pathway, not as a protease inhibitor. While it shares alpha-2-macroglobulin domains with protease inhibitors, the TEP family has diverged to function primarily in pathogen opsonization rather than protease inhibition. This is well established for TEP1 in A. gambiae and applies by homology to TEP2. The annotation represents an over-annotation based solely on domain homology without consideration of the functional divergence of the TEP family. This is the same issue identified for TEP1 annotation review.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
TEP2 belongs to the A2M/TEP family and contains the conserved thioester motif. By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin that promotes downstream effector outcomes such as phagocytosis or killing
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
Thioester-containing proteins (TEPs): Secreted innate immune effectors with a reactive thioester (GCGEQ) that can form covalent bonds with microbial surfaces. In insects, TEPs are functionally analogous to vertebrate complement factors (e.g., C3), contributing to recognition, opsonization, and clearance by phagocytosis and/or lysis
|
|
GO:0005576
extracellular region
|
IEA
GO_REF:0000120 |
ACCEPT |
Summary: This IEA annotation is derived from combined automated methods based on InterPro domains (IPR009048, IPR036595 alpha-macroglobulin receptor-binding domain) and UniProt subcellular location annotations (SL-0243 Secreted). TEP2 is predicted to be a secreted protein based on its TEP family membership and signal peptide features. The well-characterized TEP1 is secreted into the hemolymph, and TEP2 is expected to follow the same localization pattern (Baxter et al., 2010).
Reason: The annotation is consistent with TEP family biology. TEP proteins are secreted into the hemolymph (extracellular region in insects) where they circulate until activated and deposited on pathogen surfaces. The UniProt entry confirms secreted localization based on ARBA annotation. While direct experimental evidence for TEP2 localization is lacking, the inference from TEP family membership and conserved architecture is strong.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
Mosquito complement-like TEPs (exemplified by TEP1) are secreted into the hemolymph, where they circulate and are activated/targeted to pathogen surfaces. Given TEP2's conserved signal features within the TEP family and genomic clustering with other secreted TEPs, TEP2 is expected to be a secreted hemolymph protein
file:ANOGA/TEP2/TEP2-uniprot.txt
SUBCELLULAR LOCATION: Secreted {ECO:0000256|ARBA:ARBA00004613}
|
|
GO:0005615
extracellular space
|
IEA
GO_REF:0000120 |
ACCEPT |
Summary: This IEA annotation is based on InterPro domain mapping (IPR011626 A2M_TED thioester domain) and ARBA rule mapping (ARBA00027728). TEP2 is predicted to circulate in the hemolymph (extracellular space of insects) similar to TEP1, which forms a complex with LRIM1/APL1C in the hemolymph. The extracellular space annotation is appropriate for hemolymph-circulating proteins.
Reason: The annotation is consistent with TEP family biology. Hemolymph is the extracellular space in insects where TEP proteins circulate. TEP1 has been demonstrated to circulate in the hemolymph as part of a complex with LRIM1/APL1C, and TEP2 is expected to follow a similar localization pattern based on conserved domain architecture. This annotation is more specific than "extracellular region" and appropriately captures the circulating nature of TEP proteins.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
Given TEP2's conserved signal features within the TEP family and genomic clustering with other secreted TEPs, TEP2 is expected to be a secreted hemolymph protein (inference from family and TEP1 data)
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
In the canonical mosquito complement-like pathway, TEP1 is stabilized and delivered by LRIM1/APL1C until deposition on pathogens
|
|
GO:0045087
innate immune response
|
ISS
DOI:10.3389/fimmu.2017.00759 |
NEW |
Summary: TEP2 is predicted to participate in innate immune response based on its membership in the TEP family and conserved thioester motif. The protein shows significant upregulation (~9-fold) in mosGILT-null mosquitoes, demonstrating responsiveness to immune pathway perturbation.
Reason: While GO:0002376 "immune system process" is already annotated, this more specific term "innate immune response" better captures the nature of TEP2 function as a complement-like protein. TEPs function in the germline-encoded innate immune system, not adaptive immunity. The term is supported by TEP family membership and immune-regulated expression.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
Thioester-containing proteins (TEPs): Secreted innate immune effectors with a reactive thioester (GCGEQ) that can form covalent bonds with microbial surfaces. In insects, TEPs are functionally analogous to vertebrate complement factors (e.g., C3), contributing to recognition, opsonization, and clearance by phagocytosis and/or lysis
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001)
|
|
GO:0008228
opsonization
|
ISS
DOI:10.3389/fimmu.2017.00759 |
NEW |
Summary: TEP2 is predicted to function as an opsonin based on its conserved thioester motif (GCGEQ) and TEP family membership. The reactive thioester enables covalent attachment to pathogen surfaces, marking them for destruction by phagocytosis or melanization.
Reason: Opsonization is the predicted primary biological process of TEP2 based on homology to TEP1 and conserved domain architecture. The thioester motif is characteristic of complement-like opsonins. While direct experimental evidence for TEP2-mediated opsonization is lacking, the inference from TEP family function is strong.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
TEP2 belongs to the A2M/TEP family and contains the conserved thioester motif. By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin that promotes downstream effector outcomes such as phagocytosis or killing
|
|
GO:0140272
exogenous protein binding
|
ISS
DOI:10.3389/fimmu.2017.00759 |
NEW |
Summary: TEP2 is predicted to bind to pathogen surfaces via its reactive thioester motif. This molecular function enables opsonization of pathogens for subsequent clearance by phagocytosis or melanization.
Reason: As a complement-like opsonin, TEP2 binds to proteins/molecules on pathogen surfaces (exogenous proteins). The thioester motif allows covalent attachment to microbial surfaces. This is the appropriate molecular function term for the opsonin activity.
Supporting Evidence:
file:ANOGA/TEP2/TEP2-deep-research-falcon.md
By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin
|
Q: Does TEP2 interact with LRIM1/APL1C heterodimer similar to TEP1, and if so, is this interaction required for stabilization and delivery to pathogen surfaces?
Q: What is the specific role of TEP2 versus TEP1 and other TEPs in the A. gambiae complement-like pathway? Is there functional redundancy or specificity?
Q: Does TEP2 contribute to anti-Plasmodium immunity like TEP1, or does it have different pathogen specificity?
Experiment: RNAi knockdown of TEP2 followed by bacterial or fungal infection challenge to assess immune function.
Hypothesis: TEP2 knockdown will increase pathogen proliferation and reduce mosquito survival, similar to TEP1 knockdown phenotypes.
Experiment: Co-immunoprecipitation studies to determine if TEP2 interacts with LRIM1/APL1C or other hemolymph proteins.
Hypothesis: TEP2 forms a circulating complex with LRIM1/APL1C similar to TEP1.
Experiment: Immunolocalization of TEP2 during pathogen challenge to determine if it deposits on pathogen surfaces.
Hypothesis: TEP2 will accumulate on pathogen surfaces similar to TEP1 opsonization.
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organism: ANOGA
gene_id: TEP2
gene_symbol: TEP2
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protein_description: 'RecName: Full=TEP1-F {ECO:0000256|ARBA:ARBA00078071};'
gene_info: Name=TEP2 {ECO:0000313|EMBL:EAL39586.4}; Synonyms=3291704 {ECO:0000313|EnsemblMetazoa:AGAP008366-PA};
ORFNames=AgaP_AGAP008366 {ECO:0000313|EMBL:EAL39586.4};
organism_full: Anopheles gambiae (African malaria mosquito).
protein_family: Belongs to the protease inhibitor I39 (alpha-2-
protein_domains: A-macroglobulin_rcpt-bd. (IPR009048); A-macroglobulin_rcpt-bd_sf.
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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 'TEP2' 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 TEP2 (gene ID: TEP2, UniProt: Q5TQC0) 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 'TEP2' 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 TEP2 (gene ID: TEP2, UniProt: Q5TQC0) 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 overview
- Verified identity and scope: The target is Anopheles gambiae TEP2 (AGAP008366), a thioester-containing protein (TEP) of the alpha-2-macroglobulin/complement-like family, UniProt Q5TQC0. The gene resides in a TEP cluster on chromosome 3R and carries an intact thioester (TE) motif. To avoid symbol ambiguity, all functional inferences below pertain to An. gambiae TEP2, not Drosophila Tep2 or vertebrate TEPs (christophides2002immunityrelatedgenesand pages 4-6, christophides2002immunityrelatedgenesand pages 6-7).
1) Key concepts and definitions
- Thioester-containing proteins (TEPs): Secreted innate immune effectors with a reactive thioester (GCGEQ) that can form covalent bonds with microbial surfaces. In insects, TEPs are functionally analogous to vertebrate complement factors (e.g., C3), contributing to recognition, opsonization, and clearance by phagocytosis and/or lysis. The family also includes alpha-2-macroglobulin-like protease inhibitors with related architectural features (shokal2017evolutionandfunction pages 2-4, shokal2017evolutionandfunction pages 1-2). URL: https://doi.org/10.3389/fimmu.2017.00759 (published Jun 29, 2017).
- Anopheles TEP system: In A. gambiae, the complement-like pathway centers on TEP1, which circulates in hemolymph, is proteolytically processed (TEP1cut), and is stabilized by the LRIM1/APL1C heterodimeric complex until deployment on pathogen surfaces. These interactions exemplify core principles likely shared across mosquito TEPs, including secretion to hemolymph and regulated activation on target surfaces (baxter2010aheterodimericcomplex pages 1-2). URL: https://doi.org/10.1073/pnas.1010575107 (published Sep 28, 2010).
- Target identity and genomic context: TEP2 is a distinct An. gambiae TEP gene in a multi-gene cluster on chromosome arm 3R (29Aβ30E). TEP2 lies very close to TEP15, with other TEPs (TEP12β14) located farther within the same region. TEP2 is annotated with a present thioester (TE) motif, consistent with complement-like opsonin function (christophides2002immunityrelatedgenesand pages 4-6, christophides2002immunityrelatedgenesand pages 6-7). URL: https://doi.org/10.1126/science.1077136 (published Oct 4, 2002).
2) Recent developments and latest research (priority 2023β2024)
- Transcriptomic regulation linking TEP2 to immune and reproductive physiology: In gene-edited mosGILT-null A. gambiae, whole-body RNA-seq revealed significant upregulation of TEP2 (AGAP008366) by ~9-fold (p=0.0001), alongside other TEPs. The study connects mosGILT to modulation of complement activity and innate immunity, providing contemporary evidence that TEP2 is dynamically regulated with immune pathway perturbations (arora2024mosgiltcontrolsinnate pages 5-7). URL: https://doi.org/10.1186/s12864-023-09887-0 (published Jan 2024).
- Preprint corroboration: The same research groupβs 2023 preprint similarly reported increased expression of TEP2 (AGAP008366) in mosGILT-null mosquitoes, reinforcing the regulatory link across datasets (arora2023anophelesgambiaemosgilt pages 10-15). URL: https://doi.org/10.1101/2023.08.01.551536 (posted Aug 2023).
- Population genomics context: A multi-country GWAS of insecticide resistance in A. gambiae/coluzzii detected cross-insecticide association signals spanning regions containing Tep family genes (e.g., Tep1/Tep4), highlighting immune gene neighborhoods as potential contributors to complex resistance phenotypes. While not isolating TEP2 specifically, the findings implicate TEP loci as potential hubs under selection in contemporary field populations (lucas2023genomewideassociationstudies pages 7-8). URL: https://doi.org/10.1038/s41467-023-40693-0 (published Aug 2023).
3) Function, mechanism, and pathways (integrating precise evidence and inference)
- Domain architecture and inferred mechanism: TEP2 belongs to the A2M/TEP family and contains the conserved thioester motif. By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin that promotes downstream effector outcomes such as phagocytosis or killing. This mechanistic inference is grounded in the conserved TEP architecture and well-characterized TEP1 biology in An. gambiae (shokal2017evolutionandfunction pages 2-4, shokal2017evolutionandfunction pages 1-2, baxter2010aheterodimericcomplex pages 1-2). URLs: 2017 review https://doi.org/10.3389/fimmu.2017.00759; 2010 structural/biochemical study https://doi.org/10.1073/pnas.1010575107.
- Pathway integration and interacting modules: In the canonical mosquito complement-like pathway, TEP1 is stabilized and delivered by LRIM1/APL1C until deposition on pathogens; SPCLIP1 regulates TEP1 recruitment to microbial surfaces. While direct biochemical interaction data for TEP2 with LRIM1/APL1C are not available in the gathered sources, the shared TEP architecture and clustered genomic organization suggest that TEP2 likely participates in extracellular complement-like immunity in hemolymph, potentially coordinated with LRIM/APL1 modules. This is an informed inference based on TEP family principles and the Anopheles complement-like paradigm (baxter2010aheterodimericcomplex pages 1-2, shokal2017evolutionandfunction pages 2-4). URL: https://doi.org/10.1073/pnas.1010575107; https://doi.org/10.3389/fimmu.2017.00759.
- Specific roles: There is strong evidence for TEP1-mediated opsonization and parasite killing in A. gambiae, and for TEP family roles in opsonization and melanization cascades in insects. However, direct phenotypic evidence uniquely assigning opsonization, melanization, or phagocytosis roles to An. gambiae TEP2 was not identified in the 2023β2024 literature sampled here. Thus, TEP2βs primary function is best described as a secreted, thioester-bearing complement-like protein with predicted opsonin activity by homology, pending direct experimental validation (shokal2017evolutionandfunction pages 2-4, shokal2017evolutionandfunction pages 1-2). URL: https://doi.org/10.3389/fimmu.2017.00759.
4) Localization, expression, and regulation
- Extracellular localization: Mosquito complement-like TEPs (exemplified by TEP1) are secreted into the hemolymph, where they circulate and are activated/targeted to pathogen surfaces. Given TEP2βs conserved signal features within the TEP family and genomic clustering with other secreted TEPs, TEP2 is expected to be a secreted hemolymph protein (inference from family and TEP1 data) (baxter2010aheterodimericcomplex pages 1-2, shokal2017evolutionandfunction pages 2-4). URL: https://doi.org/10.1073/pnas.1010575107; https://doi.org/10.3389/fimmu.2017.00759.
- Tissue expression and inducibility: RNA-seq in mosGILT-null mosquitoes shows whole-body upregulation of TEP2 (~9Γ), suggesting responsiveness to immune pathway perturbation. Earlier work cited therein noted midgut TEP gene upregulation upon Plasmodium falciparum infection, consistent with infection-inducible regulation in the epithelium/hemolymph interface. Direct tissue-specific expression for TEP2 (e.g., fat body vs. hemocytes) was not explicitly reported in the 2023β2024 sources queried here (arora2024mosgiltcontrolsinnate pages 5-7, arora2023anophelesgambiaemosgilt pages 10-15). URL: https://doi.org/10.1186/s12864-023-09887-0; https://doi.org/10.1101/2023.08.01.551536.
- Genomic organization: TEP2 is part of a TEP cluster on 3R (29Aβ30E), lying very close to TEP15; the cluster organization supports coordinated evolution and possibly co-regulation within the family (christophides2002immunityrelatedgenesand pages 4-6, christophides2002immunityrelatedgenesand pages 6-7). URL: https://doi.org/10.1126/science.1077136.
5) Applications and real-world implementations
- Vector control and surveillance implications: Complement-like genes are major determinants of vector competence and are under selection in wild populations. The 2023 GWAS highlights Tep family regions exhibiting cross-insecticide associations, suggesting immune gene neighborhoodsβincluding TEPsβmay influence or correlate with resistance phenotypes, informing genomic surveillance strategies. While TEP2-specific selection was not isolated, Tep regions appear as multi-allelic, population-variable signals, cautioning that monitoring should account for local haplotypes and CNVs (lucas2023genomewideassociationstudies pages 7-8). URL: https://doi.org/10.1038/s41467-023-40693-0 (Aug 2023).
- Research utility: The robust upregulation of TEP2 in mosGILT-null mosquitoes links TEP2 expression to innate immune modulation and reproductive biology, providing an entry point for functional genetic tests in A. gambiae strains used by vector biology labs (arora2024mosgiltcontrolsinnate pages 5-7, arora2023anophelesgambiaemosgilt pages 10-15). URL: https://doi.org/10.1186/s12864-023-09887-0; https://doi.org/10.1101/2023.08.01.551536.
6) Expert opinions and analysis
- Complement-like architecture as a guide to function: Reviews and structural work emphasize that insect TEPs are secreted, hemolymph-borne effectors with regulated activation, covalent target tagging via a transient thioester, and interactions with LRIM/APL1 complexes. For An. gambiae, this framework is best characterized for TEP1 and provides the most reliable mechanistic scaffold for TEP2 functional hypotheses until TEP2-specific experiments are available (shokal2017evolutionandfunction pages 2-4, baxter2010aheterodimericcomplex pages 1-2). URLs: https://doi.org/10.3389/fimmu.2017.00759; https://doi.org/10.1073/pnas.1010575107.
- Gene family context and diversification: The Anopheles genome encodes an expanded TEP repertoire relative to Drosophila, with multiple clustered loci and some members lacking a TE motif. TEP2 is among the thioester-positive members, consistent with complement-like opsonin potential in Anopheles immunity (christophides2002immunityrelatedgenesand pages 4-6, christophides2002immunityrelatedgenesand pages 6-7). URL: https://doi.org/10.1126/science.1077136.
7) Quantitative data and statistics
- TEP2 expression change: In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001), indicating strong inducibility under immune/reproductive pathway perturbation (arora2024mosgiltcontrolsinnate pages 5-7, arora2023anophelesgambiaemosgilt pages 10-15). URLs: 2024 article https://doi.org/10.1186/s12864-023-09887-0; 2023 preprint https://doi.org/10.1101/2023.08.01.551536.
- GWAS signals: Cross-insecticide resistance association peaks were reported in genomic regions encompassing Tep family genes (not isolating TEP2), underscoring potential relevance of complement-like immunity loci to adaptive traits in field populations (lucas2023genomewideassociationstudies pages 7-8). URL: https://doi.org/10.1038/s41467-023-40693-0.
Ambiguity and limitations explicitly addressed
- Symbol ambiguity: βTEP2β is used in multiple insects; here it denotes Anopheles gambiae TEP2 (AGAP008366; UniProt Q5TQC0). Reviews that discuss βTep2β in Drosophila are not directly applicable; where family-level mechanisms are invoked, they are explicitly identified as inferences from conserved architecture and A. gambiae TEP1 biology (shokal2017evolutionandfunction pages 2-4, christophides2002immunityrelatedgenesand pages 4-6).
- Evidence gaps: No 2023β2024 primary experimental study providing direct biochemical function, substrate specificity, hemolymph proteomics confirmation, or genetic loss-of-function phenotypes for An. gambiae TEP2 was found in the gathered sources. Functional roles are therefore inferred from TEP family principles, genomic context, and expression regulation, and should be validated with TEP2-specific perturbation studies in A. gambiae (shokal2017evolutionandfunction pages 2-4, arora2024mosgiltcontrolsinnate pages 5-7).
Concise functional annotation for An. gambiae TEP2 (AGAP008366; UniProt Q5TQC0)
- Molecular function: Predicted complement-like opsonin with a reactive thioester; covalent tagging of pathogen surfaces is inferred by homology to An. gambiae TEP1 and conserved domain features (shokal2017evolutionandfunction pages 2-4, baxter2010aheterodimericcomplex pages 1-2).
- Biological processes: Innate immune response in hemolymph; likely contributes to pathogen recognition/opsonization and downstream effector mechanisms (phagocytosis or melanization) as part of the mosquito complement-like pathway; inducible in immune pathway perturbation (shokal2017evolutionandfunction pages 2-4, arora2024mosgiltcontrolsinnate pages 5-7).
- Cellular/extracellular localization: Secreted to hemolymph (inferred from TEP family and TEP1 paradigm) (baxter2010aheterodimericcomplex pages 1-2, shokal2017evolutionandfunction pages 2-4).
- Pathways: Mosquito complement-like cascade coordinated by LRIM1/APL1C carrier complex and serine protease regulators; direct interaction of TEP2 with LRIM/APL1 not yet reported in the sources gathered here; genomic clustering suggests shared regulation with neighboring TEPs (baxter2010aheterodimericcomplex pages 1-2, christophides2002immunityrelatedgenesand pages 4-6).
Citations
- Shokal U, Eleftherianos I. Evolution and Function of Thioester-Containing Proteins and the Complement System in the Innate Immune Response. Front Immunol. 2017;8:759. https://doi.org/10.3389/fimmu.2017.00759 (Jun 29, 2017) (shokal2017evolutionandfunction pages 2-4, shokal2017evolutionandfunction pages 1-2).
- Baxter RHG, et al. A heterodimeric complex of the LRR proteins LRIM1 and APL1C regulates complement-like immunity in Anopheles gambiae. PNAS. 2010;107(39):16817β16822. https://doi.org/10.1073/pnas.1010575107 (Sep 28, 2010) (baxter2010aheterodimericcomplex pages 1-2).
- Christophides GK, et al. Immunity-Related Genes and Gene Families in Anopheles gambiae. Science. 2002;298(5591):159β165. https://doi.org/10.1126/science.1077136 (Oct 4, 2002) (christophides2002immunityrelatedgenesand pages 4-6, christophides2002immunityrelatedgenesand pages 6-7).
- Arora G, et al. mosGILT controls innate immunity and germ cell development in Anopheles gambiae. BMC Genomics. 2024;25:1β12. https://doi.org/10.1186/s12864-023-09887-0 (Jan 2024) (arora2024mosgiltcontrolsinnate pages 5-7).
- Arora G, et al. Anopheles gambiae mosGILT regulates innate immune genes and zpg expression. bioRxiv. 2023. https://doi.org/10.1101/2023.08.01.551536 (Aug 2023) (arora2023anophelesgambiaemosgilt pages 10-15).
- Lucas ER, et al. Genome-wide association studies reveal novel loci associated with pyrethroid and organophosphate resistance in Anopheles gambiae and Anopheles coluzzii. Nat Commun. 2023;14:4946. https://doi.org/10.1038/s41467-023-40693-0 (Aug 2023) (lucas2023genomewideassociationstudies pages 7-8).
References
(christophides2002immunityrelatedgenesand pages 4-6): George K. Christophides, Evgeny Zdobnov, Carolina Barillas-Mury, Ewan Birney, Stephanie Blandin, Claudia Blass, Paul T. Brey, Frank H. Collins, Alberto Danielli, George Dimopoulos, Charles Hetru, Ngo T. Hoa, Jules A. Hoffmann, Stefan M. Kanzok, Ivica Letunic, Elena A. Levashina, Thanasis G. Loukeris, Gareth Lycett, Stephan Meister, Kristin Michel, Luis F. Moita, Hans-Michael MuΜller, Mike A. Osta, Susan M. Paskewitz, Jean-Marc Reichhart, Andrey Rzhetsky, Laurent Troxler, Kenneth D. Vernick, Dina Vlachou, Jennifer Volz, Christian von Mering, Jiannong Xu, Liangbiao Zheng, Peer Bork, and Fotis C. Kafatos. Immunity-related genes and gene families in anopheles gambiae. Science, 298:159-165, Oct 2002. URL: https://doi.org/10.1126/science.1077136, doi:10.1126/science.1077136. This article has 1191 citations and is from a highest quality peer-reviewed journal.
(christophides2002immunityrelatedgenesand pages 6-7): George K. Christophides, Evgeny Zdobnov, Carolina Barillas-Mury, Ewan Birney, Stephanie Blandin, Claudia Blass, Paul T. Brey, Frank H. Collins, Alberto Danielli, George Dimopoulos, Charles Hetru, Ngo T. Hoa, Jules A. Hoffmann, Stefan M. Kanzok, Ivica Letunic, Elena A. Levashina, Thanasis G. Loukeris, Gareth Lycett, Stephan Meister, Kristin Michel, Luis F. Moita, Hans-Michael MuΜller, Mike A. Osta, Susan M. Paskewitz, Jean-Marc Reichhart, Andrey Rzhetsky, Laurent Troxler, Kenneth D. Vernick, Dina Vlachou, Jennifer Volz, Christian von Mering, Jiannong Xu, Liangbiao Zheng, Peer Bork, and Fotis C. Kafatos. Immunity-related genes and gene families in anopheles gambiae. Science, 298:159-165, Oct 2002. URL: https://doi.org/10.1126/science.1077136, doi:10.1126/science.1077136. This article has 1191 citations and is from a highest quality peer-reviewed journal.
(shokal2017evolutionandfunction pages 2-4): Upasana Shokal and Ioannis Eleftherianos. Evolution and function of thioester-containing proteins and the complement system in the innate immune response. Frontiers in Immunology, Jun 2017. URL: https://doi.org/10.3389/fimmu.2017.00759, doi:10.3389/fimmu.2017.00759. This article has 138 citations and is from a peer-reviewed journal.
(shokal2017evolutionandfunction pages 1-2): Upasana Shokal and Ioannis Eleftherianos. Evolution and function of thioester-containing proteins and the complement system in the innate immune response. Frontiers in Immunology, Jun 2017. URL: https://doi.org/10.3389/fimmu.2017.00759, doi:10.3389/fimmu.2017.00759. This article has 138 citations and is from a peer-reviewed journal.
(baxter2010aheterodimericcomplex pages 1-2): Richard H. G. Baxter, Stefanie Steinert, Yogarany Chelliah, Gloria Volohonsky, Elena A. Levashina, and Johann Deisenhofer. A heterodimeric complex of the lrr proteins lrim1 and apl1c regulates complement-like immunity in anopheles gambiae. Proceedings of the National Academy of Sciences, 107:16817-16822, Sep 2010. URL: https://doi.org/10.1073/pnas.1010575107, doi:10.1073/pnas.1010575107. This article has 76 citations and is from a highest quality peer-reviewed journal.
(arora2024mosgiltcontrolsinnate pages 5-7): Gunjan Arora, Xiaotian Tang, Yingjun Cui, Jing Yang, Yu-Min Chuang, Jayadev Joshi, Andaleeb Sajid, Yuemei Dong, Peter Cresswell, George Dimopoulos, and Erol Fikrig. Mosgilt controls innate immunity and germ cell development in anopheles gambiae. BMC Genomics, 25:1-12, Jan 2024. URL: https://doi.org/10.1186/s12864-023-09887-0, doi:10.1186/s12864-023-09887-0. This article has 8 citations and is from a peer-reviewed journal.
(arora2023anophelesgambiaemosgilt pages 10-15): Gunjan Arora, Xiaotian Tang, Yingjun Cui, Jing Yang, Yu-Min Chuang, Jayadev Joshi, Andaleeb Sajid, Yuemei Dong, Peter Cresswell, George Dimopoulos, and Erol Fikrig. Anopheles gambiae mosgilt regulates innate immune genes and zpg expression. bioRxiv, Aug 2023. URL: https://doi.org/10.1101/2023.08.01.551536, doi:10.1101/2023.08.01.551536. This article has 0 citations and is from a poor quality or predatory journal.
(lucas2023genomewideassociationstudies pages 7-8): Eric R. Lucas, Sanjay C. Nagi, Alexander Egyir-Yawson, John Essandoh, Samuel Dadzie, Joseph Chabi, Luc S. DjogbΓ©nou, AdandΓ© A. Medjigbodo, Constant V. Edi, Guillaume K. KΓ©toh, Benjamin G. Koudou, Arjen E. Vanβt Hof, Emily J. Rippon, Dimitra Pipini, Nicholas J. Harding, Naomi A. Dyer, Louise T. Cerdeira, Chris S. Clarkson, Dominic P. Kwiatkowski, Alistair Miles, Martin J. Donnelly, and David Weetman. Genome-wide association studies reveal novel loci associated with pyrethroid and organophosphate resistance in anopheles gambiae and anopheles coluzzii. Nature Communications, Aug 2023. URL: https://doi.org/10.1038/s41467-023-40693-0, doi:10.1038/s41467-023-40693-0. This article has 70 citations and is from a highest quality peer-reviewed journal.
id: Q5TQC0
gene_symbol: TEP2
product_type: PROTEIN
status: COMPLETE
taxon:
id: NCBITaxon:7165
label: Anopheles gambiae
description: >-
TEP2 (Thioester-containing protein 2) is a secreted complement-like protein
belonging to the alpha-2-macroglobulin/thioester-containing protein family in
the African malaria mosquito Anopheles gambiae. TEP2 contains a conserved
thioester motif (GCGEQ) that enables covalent attachment to pathogen surfaces,
functioning as a predicted opsonin similar to the well-characterized TEP1.
The protein is encoded by gene AGAP008366 located in a TEP gene cluster on
chromosome arm 3R (29A-30E), near TEP15. While TEP1 has been extensively
studied for its role in anti-Plasmodium immunity, TEP2 remains less
characterized but is predicted to function similarly based on conserved domain
architecture. TEP2 expression is induced ~9-fold in mosGILT-null mosquitoes,
indicating responsiveness to immune pathway perturbation. The protein is
expected to be secreted into the hemolymph where it circulates until deployment
on pathogen surfaces.
existing_annotations:
- term:
id: GO:0002376
label: immune system process
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This IEA annotation is derived from the UniProt keyword "Immunity" (KW-0391)
through automated mapping. TEP2 is a thioester-containing protein belonging
to the TEP family which functions in insect innate immunity. The protein
contains an intact thioester motif and is part of the complement-like
immune pathway in A. gambiae (Christophides et al., 2002). Expression is
significantly induced (~9-fold) in mosGILT-null mosquitoes, demonstrating
responsiveness to immune pathway perturbation (Arora et al., 2024).
action: ACCEPT
reason: >-
TEP2 is a member of the thioester-containing protein family which plays
essential roles in insect innate immunity. The annotation to "immune system
process" is technically correct and appropriate for this complement-like
protein, although it is a broad term. The induction of TEP2 in immune-perturbed
mosquitoes and its TEP family membership strongly support this annotation.
additional_reference_ids:
- DOI:10.1126/science.1077136
- DOI:10.1186/s12864-023-09887-0
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "TEP2 is a distinct An. gambiae TEP gene in a multi-gene cluster on chromosome arm 3R (29A-30E). TEP2 lies very close to TEP15, with other TEPs (TEP12-14) located farther within the same region. TEP2 is annotated with a present thioester (TE) motif, consistent with complement-like opsonin function"
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001), indicating strong inducibility under immune/reproductive pathway perturbation"
- term:
id: GO:0004866
label: endopeptidase inhibitor activity
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
This annotation is derived from InterPro domain mapping (IPR001599 Alpha-2-
macroglobulin and IPR002890 MG2 domain) which are shared with protease
inhibitors like alpha-2-macroglobulin. However, TEP2 is a thioester-containing
protein that belongs to the complement-like branch of this family, not the
protease inhibitor branch. Similar to the well-characterized TEP1 in A. gambiae,
TEP2 is predicted to function as an opsonin that covalently tags pathogen
surfaces via its reactive thioester bond, not as a protease inhibitor
(Shokal and Eleftherianos, 2017). There is no experimental evidence that
TEP2 acts as an endopeptidase inhibitor.
action: REMOVE
reason: >-
TEP2 is a thioester-containing protein that functions as a predicted
complement-like opsonin in the insect innate immune pathway, not as a
protease inhibitor. While it shares alpha-2-macroglobulin domains with
protease inhibitors, the TEP family has diverged to function primarily in
pathogen opsonization rather than protease inhibition. This is well
established for TEP1 in A. gambiae and applies by homology to TEP2. The
annotation represents an over-annotation based solely on domain homology
without consideration of the functional divergence of the TEP family.
This is the same issue identified for TEP1 annotation review.
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "TEP2 belongs to the A2M/TEP family and contains the conserved thioester motif. By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin that promotes downstream effector outcomes such as phagocytosis or killing"
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "Thioester-containing proteins (TEPs): Secreted innate immune effectors with a reactive thioester (GCGEQ) that can form covalent bonds with microbial surfaces. In insects, TEPs are functionally analogous to vertebrate complement factors (e.g., C3), contributing to recognition, opsonization, and clearance by phagocytosis and/or lysis"
- term:
id: GO:0005576
label: extracellular region
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: >-
This IEA annotation is derived from combined automated methods based on
InterPro domains (IPR009048, IPR036595 alpha-macroglobulin receptor-binding
domain) and UniProt subcellular location annotations (SL-0243 Secreted).
TEP2 is predicted to be a secreted protein based on its TEP family
membership and signal peptide features. The well-characterized TEP1 is
secreted into the hemolymph, and TEP2 is expected to follow the same
localization pattern (Baxter et al., 2010).
action: ACCEPT
reason: >-
The annotation is consistent with TEP family biology. TEP proteins are
secreted into the hemolymph (extracellular region in insects) where they
circulate until activated and deposited on pathogen surfaces. The UniProt
entry confirms secreted localization based on ARBA annotation. While
direct experimental evidence for TEP2 localization is lacking, the
inference from TEP family membership and conserved architecture is strong.
additional_reference_ids:
- DOI:10.1073/pnas.1010575107
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "Mosquito complement-like TEPs (exemplified by TEP1) are secreted into the hemolymph, where they circulate and are activated/targeted to pathogen surfaces. Given TEP2's conserved signal features within the TEP family and genomic clustering with other secreted TEPs, TEP2 is expected to be a secreted hemolymph protein"
- reference_id: file:ANOGA/TEP2/TEP2-uniprot.txt
supporting_text: "SUBCELLULAR LOCATION: Secreted {ECO:0000256|ARBA:ARBA00004613}"
- term:
id: GO:0005615
label: extracellular space
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: >-
This IEA annotation is based on InterPro domain mapping (IPR011626 A2M_TED
thioester domain) and ARBA rule mapping (ARBA00027728). TEP2 is predicted
to circulate in the hemolymph (extracellular space of insects) similar to
TEP1, which forms a complex with LRIM1/APL1C in the hemolymph. The
extracellular space annotation is appropriate for hemolymph-circulating
proteins.
action: ACCEPT
reason: >-
The annotation is consistent with TEP family biology. Hemolymph is the
extracellular space in insects where TEP proteins circulate. TEP1 has
been demonstrated to circulate in the hemolymph as part of a complex with
LRIM1/APL1C, and TEP2 is expected to follow a similar localization pattern
based on conserved domain architecture. This annotation is more specific
than "extracellular region" and appropriately captures the circulating
nature of TEP proteins.
additional_reference_ids:
- DOI:10.1073/pnas.1010575107
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "Given TEP2's conserved signal features within the TEP family and genomic clustering with other secreted TEPs, TEP2 is expected to be a secreted hemolymph protein (inference from family and TEP1 data)"
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "In the canonical mosquito complement-like pathway, TEP1 is stabilized and delivered by LRIM1/APL1C until deposition on pathogens"
# Suggested new annotations based on inferred function from TEP family membership
- term:
id: GO:0045087
label: innate immune response
evidence_type: ISS
original_reference_id: DOI:10.3389/fimmu.2017.00759
review:
summary: >-
TEP2 is predicted to participate in innate immune response based on its
membership in the TEP family and conserved thioester motif. The protein
shows significant upregulation (~9-fold) in mosGILT-null mosquitoes,
demonstrating responsiveness to immune pathway perturbation.
action: NEW
reason: >-
While GO:0002376 "immune system process" is already annotated, this more
specific term "innate immune response" better captures the nature of TEP2
function as a complement-like protein. TEPs function in the germline-encoded
innate immune system, not adaptive immunity. The term is supported by
TEP family membership and immune-regulated expression.
additional_reference_ids:
- DOI:10.1186/s12864-023-09887-0
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "Thioester-containing proteins (TEPs): Secreted innate immune effectors with a reactive thioester (GCGEQ) that can form covalent bonds with microbial surfaces. In insects, TEPs are functionally analogous to vertebrate complement factors (e.g., C3), contributing to recognition, opsonization, and clearance by phagocytosis and/or lysis"
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001)"
- term:
id: GO:0008228
label: opsonization
evidence_type: ISS
original_reference_id: DOI:10.3389/fimmu.2017.00759
review:
summary: >-
TEP2 is predicted to function as an opsonin based on its conserved
thioester motif (GCGEQ) and TEP family membership. The reactive thioester
enables covalent attachment to pathogen surfaces, marking them for
destruction by phagocytosis or melanization.
action: NEW
reason: >-
Opsonization is the predicted primary biological process of TEP2 based on
homology to TEP1 and conserved domain architecture. The thioester motif
is characteristic of complement-like opsonins. While direct experimental
evidence for TEP2-mediated opsonization is lacking, the inference from
TEP family function is strong.
additional_reference_ids:
- DOI:10.1073/pnas.1010575107
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "TEP2 belongs to the A2M/TEP family and contains the conserved thioester motif. By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin that promotes downstream effector outcomes such as phagocytosis or killing"
- term:
id: GO:0140272
label: exogenous protein binding
evidence_type: ISS
original_reference_id: DOI:10.3389/fimmu.2017.00759
review:
summary: >-
TEP2 is predicted to bind to pathogen surfaces via its reactive thioester
motif. This molecular function enables opsonization of pathogens for
subsequent clearance by phagocytosis or melanization.
action: NEW
reason: >-
As a complement-like opsonin, TEP2 binds to proteins/molecules on pathogen
surfaces (exogenous proteins). The thioester motif allows covalent
attachment to microbial surfaces. This is the appropriate molecular
function term for the opsonin activity.
additional_reference_ids:
- DOI:10.1073/pnas.1010575107
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin"
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000043
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
findings: []
- id: GO_REF:0000120
title: Combined Automated Annotation using Multiple IEA Methods
findings: []
- id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
title: Deep research report on TEP2 in Anopheles gambiae
findings:
- statement: TEP2 is a thioester-containing protein in a gene cluster on chromosome 3R
supporting_text: "TEP2 is a distinct An. gambiae TEP gene in a multi-gene cluster on chromosome arm 3R (29A-30E). TEP2 lies very close to TEP15"
- statement: TEP2 has an intact thioester motif consistent with opsonin function
supporting_text: "TEP2 is annotated with a present thioester (TE) motif, consistent with complement-like opsonin function"
- statement: TEP2 is induced in immune-perturbed mosquitoes
supporting_text: "In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001)"
- id: file:ANOGA/TEP2/TEP2-uniprot.txt
title: UniProt entry for TEP2 (Q5TQC0)
findings:
- statement: TEP2 is predicted to be secreted
supporting_text: "SUBCELLULAR LOCATION: Secreted {ECO:0000256|ARBA:ARBA00004613}"
- id: DOI:10.1126/science.1077136
title: Immunity-related genes and gene families in Anopheles gambiae
findings:
- statement: TEP2 is located in a TEP gene cluster on chromosome 3R
supporting_text: "TEP2 is a distinct An. gambiae TEP gene in a multi-gene cluster on chromosome arm 3R (29A-30E)"
- statement: TEP2 has an intact thioester motif
supporting_text: "TEP2 is annotated with a present thioester (TE) motif, consistent with complement-like opsonin function"
- id: DOI:10.3389/fimmu.2017.00759
title: Evolution and Function of Thioester-Containing Proteins and the Complement System in the Innate Immune Response
findings:
- statement: TEPs function as innate immune effectors via thioester-mediated pathogen binding
supporting_text: "Thioester-containing proteins (TEPs): Secreted innate immune effectors with a reactive thioester (GCGEQ) that can form covalent bonds with microbial surfaces"
- statement: Insect TEPs are functionally analogous to vertebrate complement
supporting_text: "In insects, TEPs are functionally analogous to vertebrate complement factors (e.g., C3), contributing to recognition, opsonization, and clearance by phagocytosis and/or lysis"
- id: DOI:10.1073/pnas.1010575107
title: A heterodimeric complex of the LRR proteins LRIM1 and APL1C regulates complement-like immunity in Anopheles gambiae
findings:
- statement: TEP1 circulates in hemolymph in complex with LRIM1/APL1C
supporting_text: "In the canonical mosquito complement-like pathway, TEP1 is stabilized and delivered by LRIM1/APL1C until deposition on pathogens"
- id: DOI:10.1186/s12864-023-09887-0
title: mosGILT controls innate immunity and germ cell development in Anopheles gambiae
findings:
- statement: TEP2 is strongly induced in immune-perturbed mosquitoes
supporting_text: "In A. gambiae mosGILT-null, TEP2 (AGAP008366) whole-body transcript levels increased ~9-fold versus wild type (p=0.0001)"
core_functions:
- molecular_function:
id: GO:0140272
label: exogenous protein binding
description: >-
TEP2 is a secreted thioester-containing protein predicted to function as an
opsonin in the insect complement-like pathway. It contains a conserved
thioester motif (GCGEQ) that is predicted to enable covalent attachment to
pathogen surfaces, marking pathogens for destruction by phagocytosis or
melanization. The functional inference is based on homology to the
well-characterized TEP1 and conserved TEP family architecture.
directly_involved_in:
- id: GO:0008228
label: opsonization
- id: GO:0045087
label: innate immune response
locations:
- id: GO:0005615
label: extracellular space
- id: GO:0005576
label: extracellular region
supported_by:
- reference_id: file:ANOGA/TEP2/TEP2-deep-research-falcon.md
supporting_text: "TEP2 belongs to the A2M/TEP family and contains the conserved thioester motif. By analogy to complement-like TEPs in mosquitoes, the active thioester can mediate covalent attachment to microbial surfaces, serving as an opsonin"
proposed_new_terms: []
suggested_questions:
- question: >-
Does TEP2 interact with LRIM1/APL1C heterodimer similar to TEP1, and if so,
is this interaction required for stabilization and delivery to pathogen surfaces?
- question: >-
What is the specific role of TEP2 versus TEP1 and other TEPs in the A. gambiae
complement-like pathway? Is there functional redundancy or specificity?
- question: >-
Does TEP2 contribute to anti-Plasmodium immunity like TEP1, or does it have
different pathogen specificity?
suggested_experiments:
- description: >-
RNAi knockdown of TEP2 followed by bacterial or fungal infection challenge
to assess immune function.
hypothesis: >-
TEP2 knockdown will increase pathogen proliferation and reduce mosquito
survival, similar to TEP1 knockdown phenotypes.
- description: >-
Co-immunoprecipitation studies to determine if TEP2 interacts with
LRIM1/APL1C or other hemolymph proteins.
hypothesis: >-
TEP2 forms a circulating complex with LRIM1/APL1C similar to TEP1.
- description: >-
Immunolocalization of TEP2 during pathogen challenge to determine if it
deposits on pathogen surfaces.
hypothesis: >-
TEP2 will accumulate on pathogen surfaces similar to TEP1 opsonization.