TODO: Add description for APLP1
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0007409
axonogenesis
|
IBA
GO_REF:0000033 |
KEEP AS NON CORE |
Summary: APLP1 has reported neurite outgrowth activity consistent with axonogenesis, but evidence is indirect.
Reason: UniProt notes APLP1 can regulate neurite outgrowth through extracellular matrix binding. This supports a link to axonogenesis, but it is not the primary documented function.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I.
|
|
GO:0007417
central nervous system development
|
IBA
GO_REF:0000033 |
KEEP AS NON CORE |
Summary: APLP1 is brain-enriched and localized to postsynaptic density, supporting CNS relevance but not specific developmental evidence.
Reason: Expression and localization in cerebral cortex support CNS relevance, but the available references do not demonstrate a defined developmental role.
Supporting Evidence:
PMID:9521588
APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density.
|
|
GO:0005794
Golgi apparatus
|
IBA
GO_REF:0000033 |
KEEP AS NON CORE |
Summary: Golgi association is limited to processing of the C30 fragment; not a primary localization.
Reason: UniProt specifies C30 is processed in the Golgi complex, indicating a processing site rather than main localization of full-length APLP1.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
[C30]: Cytoplasm. Note=C-terminally processed in the Golgi complex.
|
|
GO:0005886
plasma membrane
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: APLP1 is a single-pass type I membrane protein at the cell surface.
Reason: UniProt documents APLP1 as a cell membrane protein, consistent with its receptor-like adhesion roles.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Cell membrane; Single-pass type I membrane protein.
|
|
GO:0031694
alpha-2A adrenergic receptor binding
|
IBA
GO_REF:0000033 |
KEEP AS NON CORE |
Summary: APLP1 directly binds the alpha2A-adrenergic receptor.
Reason: The interaction is experimentally demonstrated but represents a specific regulatory interaction rather than the core APLP1 function.
Supporting Evidence:
PMID:16531006
This screen identified the amyloid precursor like protein 1 (APLP1), a homologue of the beta-amyloid precursor protein involved in Alzheimer's disease, as alpha2A-adrenergic receptor-binding protein.
|
|
GO:0031695
alpha-2B adrenergic receptor binding
|
IBA
GO_REF:0000033 |
KEEP AS NON CORE |
Summary: APLP1 interacts with alpha2B-adrenergic receptor in vitro.
Reason: The interaction is demonstrated but represents a specific partner interaction rather than core APLP1 activity.
Supporting Evidence:
PMID:16531006
GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611
|
|
GO:0031696
alpha-2C adrenergic receptor binding
|
IBA
GO_REF:0000033 |
KEEP AS NON CORE |
Summary: APLP1 interacts with alpha2C-adrenergic receptor in vitro.
Reason: The interaction is demonstrated but represents a specific partner interaction rather than core APLP1 activity.
Supporting Evidence:
PMID:16531006
GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611
|
|
GO:0005737
cytoplasm
|
IEA
GO_REF:0000044 |
KEEP AS NON CORE |
Summary: Cytoplasmic localization applies to the C30 fragment rather than the full-length membrane protein.
Reason: UniProt specifies the processed C30 fragment is cytoplasmic, so this term is secondary to the membrane localization.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
[C30]: Cytoplasm. Note=C-terminally processed in the Golgi complex.
|
|
GO:0005886
plasma membrane
|
IEA
GO_REF:0000044 |
ACCEPT |
Summary: Plasma membrane localization is a core cellular component annotation for APLP1.
Reason: UniProt identifies APLP1 as a single-pass type I membrane protein at the cell membrane.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Cell membrane; Single-pass type I membrane protein.
file:genes/human/APLP1/APLP1-deep-research-falcon.md
APLP1 localizes predominantly to the neuronal cell surface compared with APP/APLP2, supporting a primary role at synapses (2018)
|
|
GO:0006897
endocytosis
|
IEA
GO_REF:0000043 |
KEEP AS NON CORE |
Summary: APLP1 contains an NPXY motif involved in clathrin-mediated endocytosis, supporting endocytic trafficking.
Reason: The NPXY motif implicated in clathrin-mediated endocytosis suggests APLP1 participates in endocytic trafficking but this is not its core function.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
The NPXY site is also involved in clathrin-mediated endocytosis.
|
|
GO:0006915
apoptotic process
|
IEA
GO_REF:0000043 |
MARK AS OVER ANNOTATED |
Summary: Evidence is fragment-specific and by-similarity; it does not support direct participation in apoptotic process for full-length APLP1.
Reason: UniProt notes the C30 fragment enhances neuronal apoptosis by similarity, which is indirect and does not justify annotating APLP1 to apoptotic process.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
The gamma-CTF peptide, C30, is a potent enhancer of neuronal apoptosis.
|
|
GO:0007155
cell adhesion
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: APP family trans-interactions promote cell-cell adhesion, consistent with APLP1 synaptic adhesion.
Reason: APLP1 forms homo/heterodimers that promote trans-cellular adhesion, supporting cell adhesion as a core function.
Supporting Evidence:
PMID:16193067
trans-interaction of APP family proteins promotes cell-cell adhesion in a homo- and heterotypic fashion
|
|
GO:0007399
nervous system development
|
IEA
GO_REF:0000117 |
KEEP AS NON CORE |
Summary: Neuronal expression supports nervous system relevance but not specific developmental evidence.
Reason: APLP1 is predominantly expressed in brain and localized to postsynaptic density; developmental roles are plausible but not directly demonstrated here.
Supporting Evidence:
PMID:9521588
APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density.
|
|
GO:0008201
heparin binding
|
IEA
GO_REF:0000120 |
KEEP AS NON CORE |
Summary: Structural evidence shows heparin binds the APLP1 E2 domain.
Reason: Heparin binding is experimentally demonstrated but represents a specific biochemical interaction rather than the primary function.
Supporting Evidence:
PMID:21930949
crystal structure of a complex between heparin and the E2 domain of APLP1
|
|
GO:0016020
membrane
|
IEA
GO_REF:0000120 |
MARK AS OVER ANNOTATED |
Summary: Generic membrane term is redundant with the more specific plasma membrane annotation.
Reason: APLP1 is a plasma membrane single-pass protein; the broad membrane term adds little value compared with GO:0005886.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Cell membrane; Single-pass type I membrane protein.
|
|
GO:0046872
metal ion binding
|
IEA
GO_REF:0000043 |
KEEP AS NON CORE |
Summary: APLP1 binds zinc and copper via its extracellular domain.
Reason: UniProt reports zinc and copper binding; this supports metal ion binding as a secondary molecular function.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Binds zinc and copper in the extracellular domain.
|
|
GO:0046914
transition metal ion binding
|
IEA
GO_REF:0000002 |
KEEP AS NON CORE |
Summary: Transition metal ion binding is supported by reported zinc/copper binding.
Reason: Zinc and copper are transition metals; UniProt notes binding in the extracellular domain.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Binds zinc and copper in the extracellular domain.
|
|
GO:0048513
animal organ development
|
IEA
GO_REF:0000117 |
MARK AS OVER ANNOTATED |
Summary: No direct evidence for animal organ development in the cited references.
Reason: The available literature focuses on gene structure and brain expression, not organ development.
Supporting Evidence:
PMID:9521588
The genomic structure has been determined.
|
|
GO:0005515
protein binding
|
IPI
PMID:16169070 A human protein-protein interaction network: a resource for ... |
MARK AS OVER ANNOTATED |
Summary: High-throughput Y2H interactome data are not specific and make protein binding uninformative here.
Reason: The study is a large-scale yeast two-hybrid screen; without a defined partner, generic protein binding adds little curation value.
Supporting Evidence:
PMID:16169070
a protein matrix of 4456 baits and 5632 preys was screened by automated yeast two-hybrid
|
|
GO:0005515
protein binding
|
IPI
PMID:16193067 Homo- and heterodimerization of APP family members promotes ... |
MODIFY |
Summary: APLP1 forms homo- and heterodimers; dimerization is more specific than generic protein binding.
Reason: The study shows APLP1 participates in homo- and heterocomplex formation, which is best captured by a dimerization term.
Proposed replacements:
protein dimerization activity
Supporting Evidence:
PMID:16193067
all three paralogs are capable of forming homo- and heterocomplexes.
|
|
GO:0005515
protein binding
|
IPI
PMID:21293490 Mediator is a transducer of amyloid-precursor-protein-depend... |
REMOVE |
Summary: The cited reference addresses APP AICD/MED12 interactions rather than APLP1.
Reason: The abstract focuses on amyloid precursor-protein (APP) AICD signaling and does not provide evidence for APLP1 binding.
Supporting Evidence:
PMID:21293490
In this study, we show that the AICD activates transcription by targeting MED12, an RNA polymerase II transcriptional Mediator subunit that is implicated in human cognitive development.
|
|
GO:0005515
protein binding
|
IPI
PMID:23864651 The identification of novel proteins that interact with the ... |
MODIFY |
Summary: APLP1 interacts with the GLP-1 receptor; a receptor-binding term is more specific than generic protein binding.
Reason: The study identifies APLP1 as a GLP-1 receptor interactor, indicating a signaling receptor binding role.
Proposed replacements:
signaling receptor binding
Supporting Evidence:
PMID:23864651
we then focused on 3 novel interactors, SLC15A4, APLP1, and AP2M1
|
|
GO:0005515
protein binding
|
IPI
PMID:32814053 Interactome Mapping Provides a Network of Neurodegenerative ... |
MARK AS OVER ANNOTATED |
Summary: Large-scale neurodegenerative interactome data are too nonspecific for a generic binding annotation.
Reason: The study reports a systematic Y2H interaction network; without a defined partner, protein binding is uninformative.
Supporting Evidence:
PMID:32814053
generated by systematic yeast two-hybrid interaction screening
|
|
GO:0042802
identical protein binding
|
IPI
PMID:16193067 Homo- and heterodimerization of APP family members promotes ... |
MODIFY |
Summary: APLP1 homodimerization is documented; a homodimerization term is more accurate.
Reason: The study demonstrates APP family homo/heterocomplexes; for identical binding, homodimerization is more specific.
Proposed replacements:
protein homodimerization activity
Supporting Evidence:
PMID:16193067
all three paralogs are capable of forming homo- and heterocomplexes.
|
|
GO:0042802
identical protein binding
|
IPI
PMID:21930949 Crystal structure of amyloid precursor-like protein 1 and he... |
MODIFY |
Summary: Heparin promotes APLP1 E2 homodimer formation, supporting homodimerization activity.
Reason: Structural data indicate E2 domain dimerization; homodimerization activity captures this more specifically than identical protein binding.
Proposed replacements:
protein homodimerization activity
Supporting Evidence:
PMID:21930949
crystal structure of a complex between heparin and the E2 domain of APLP1
|
|
GO:0005794
Golgi apparatus
|
IEA
GO_REF:0000120 |
KEEP AS NON CORE |
Summary: Golgi association reflects processing of C30 rather than main APLP1 localization.
Reason: UniProt notes C30 is processed in the Golgi complex, implying a processing site.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
[C30]: Cytoplasm. Note=C-terminally processed in the Golgi complex.
|
|
GO:0030198
extracellular matrix organization
|
ISS
GO_REF:0000024 |
MARK AS OVER ANNOTATED |
Summary: APLP1 binds extracellular matrix components but is not shown to organize ECM.
Reason: Binding to ECM components supports neurite outgrowth roles, not direct extracellular matrix organization.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I.
|
|
GO:0030900
forebrain development
|
ISS
GO_REF:0000024 |
MARK AS OVER ANNOTATED |
Summary: Forebrain development is not directly supported; only brain expression is reported.
Reason: The cited reference reports expression in cerebral cortex but does not demonstrate a developmental role.
Supporting Evidence:
PMID:9521588
APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density.
|
|
GO:0106072
negative regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway
|
IDA
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
KEEP AS NON CORE |
Summary: APLP1 enhances agonist-mediated inhibition of adenylate cyclase downstream of alpha2A-adrenergic receptor signaling.
Reason: The study reports increased norepinephrine-mediated inhibition of adenylate cyclase upon APLP1 coexpression, supporting a regulatory role in GPCR signaling.
Supporting Evidence:
PMID:16531006
cotransfection of alpha2A-adrenergic receptor and APLP1 into HEK293 cells significantly increased norepinephrine mediated inhibition of adenylate cyclase activity.
|
|
GO:0071874
cellular response to norepinephrine stimulus
|
IDA
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
KEEP AS NON CORE |
Summary: APLP1 modulates cellular responses to norepinephrine via alpha2A-adrenergic receptor signaling.
Reason: The norepinephrine response is documented in the same study but reflects a specific signaling context rather than a core APLP1 role.
Supporting Evidence:
PMID:16531006
cotransfection of alpha2A-adrenergic receptor and APLP1 into HEK293 cells significantly increased norepinephrine mediated inhibition of adenylate cyclase activity.
|
|
GO:0005886
plasma membrane
|
IDA
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
ACCEPT |
Summary: APLP1 is a plasma membrane protein, consistent with receptor interactions in the study.
Reason: Independent evidence establishes plasma membrane localization, aligning with the receptor interaction experiments.
Supporting Evidence:
file:genes/human/APLP1/APLP1-uniprot.txt
Cell membrane; Single-pass type I membrane protein.
PMID:16531006
Confocal laser microscopy showed that APLP1 causes a considerable shift of the alpha2A-adrenergic receptor localization from plasma membrane to intracellular compartments.
|
|
GO:0031694
alpha-2A adrenergic receptor binding
|
IPI
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
KEEP AS NON CORE |
Summary: APLP1 binds alpha2A-adrenergic receptor.
Reason: The interaction is experimentally shown but represents a specific regulatory partner interaction rather than a core function.
Supporting Evidence:
PMID:16531006
This screen identified the amyloid precursor like protein 1 (APLP1), a homologue of the beta-amyloid precursor protein involved in Alzheimer's disease, as alpha2A-adrenergic receptor-binding protein.
|
|
GO:0031695
alpha-2B adrenergic receptor binding
|
IPI
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
KEEP AS NON CORE |
Summary: APLP1 binds alpha2B-adrenergic receptor.
Reason: The interaction is documented but is a specific partner interaction rather than a core APLP1 activity.
Supporting Evidence:
PMID:16531006
GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611
|
|
GO:0031696
alpha-2C adrenergic receptor binding
|
IPI
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
KEEP AS NON CORE |
Summary: APLP1 binds alpha2C-adrenergic receptor.
Reason: The interaction is documented but is a specific partner interaction rather than a core APLP1 activity.
Supporting Evidence:
PMID:16531006
GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611
|
|
GO:0048471
perinuclear region of cytoplasm
|
IDA
PMID:16531006 Interaction of the amyloid precursor like protein 1 with the... |
UNDECIDED |
Summary: The study reports intracellular relocalization of alpha2A receptors, but perinuclear localization is not explicitly documented.
Reason: The abstract indicates a shift to intracellular compartments without specifying perinuclear localization; full-text evidence is needed.
Supporting Evidence:
PMID:16531006
Confocal laser microscopy showed that APLP1 causes a considerable shift of the alpha2A-adrenergic receptor localization from plasma membrane to intracellular compartments.
|
|
GO:0009887
animal organ morphogenesis
|
TAS
PMID:9521588 Structure of the human amyloid-precursor-like protein gene A... |
MARK AS OVER ANNOTATED |
Summary: The cited reference is a gene structure study and does not support organ morphogenesis.
Reason: PMID:9521588 focuses on genomic structure and expression; it does not provide morphogenesis evidence.
Supporting Evidence:
PMID:9521588
the genomic structure has been determined
|
|
GO:0005604
basement membrane
|
TAS
PMID:9521588 Structure of the human amyloid-precursor-like protein gene A... |
MARK AS OVER ANNOTATED |
Summary: Basement membrane association is speculative in the cited reference.
Reason: The paper only notes a proposed interference with basement membrane assembly as a rationale for candidacy, not direct evidence.
Supporting Evidence:
PMID:9521588
the proposed interference of amyloid with basement membrane assembly
|
|
GO:0007399
nervous system development
|
TAS
PMID:9521588 Structure of the human amyloid-precursor-like protein gene A... |
KEEP AS NON CORE |
Summary: Brain-enriched expression suggests nervous system relevance but does not directly demonstrate developmental function.
Reason: Expression in cerebral cortex supports nervous system relevance; developmental evidence is indirect.
Supporting Evidence:
PMID:9521588
APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density.
|
provider: falcon
model: Edison Scientific Literature
cached: false
start_time: '2026-01-20T18:53:04.066813'
end_time: '2026-01-20T18:59:00.245099'
duration_seconds: 356.18
template_file: templates/gene_research_go_focused.md
template_variables:
organism: human
gene_id: APLP1
gene_symbol: APLP1
uniprot_accession: P51693
protein_description: 'RecName: Full=Amyloid beta precursor like protein 1 {ECO:0000312|HGNC:HGNC:597};
AltName: Full=Amyloid beta (A4) precursor-like protein 1 {ECO:0000250|UniProtKB:Q03157};
AltName: Full=Amyloid-like protein 1 {ECO:0000312|HGNC:HGNC:597}; Short=APLP {ECO:0000312|HGNC:HGNC:597};
Short=APLP-1; Contains: RecName: Full=C30; Flags: Precursor;'
gene_info: Name=APLP1;
organism_full: Homo sapiens (Human).
protein_family: Belongs to the APP family. {ECO:0000255|PROSITE-
protein_domains: Amyloid_Cu-bd_sf. (IPR036669); Amyloid_glyco. (IPR008155); Amyloid_glyco_Cu-bd.
(IPR011178); Amyloid_glyco_E2_domain. (IPR024329); Amyloid_glyco_extra. (IPR008154)
provider_config:
timeout: 600
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citation_count: 18
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 'APLP1' 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 APLP1 (gene ID: APLP1, UniProt: P51693) in human.
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 'APLP1' 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 APLP1 (gene ID: APLP1, UniProt: P51693) in human.
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.
Comprehensive Research Report: Human APLP1 (UniProt P51693)
Executive summary and identity verification
- Identity and family: APLP1 encodes amyloid beta precursor-like protein 1, a neuron-enriched, type I transmembrane member of the APP family with conserved domain organization: an extracellular E1 region comprising a growth factor-like domain (GFLD) and a copper-binding subdomain (CuBD), an E2 domain that mediates dimerization, and a short intracellular tail with a YENPTY endocytic/adaptor-binding motif. Literature consensus matches the UniProt description and protein family/domain expectations for human APLP1 (P51693). APLP1 is distinct from APP in lacking the Aβ sequence but shares APP-family processing and adhesion roles (reviewed 2023) (chau2023amyloidprecursorprotein pages 9-10). APLP1 localizes predominantly to the neuronal cell surface compared with APP/APLP2, supporting a primary role at synapses (2018) (schauenburg2018aplp1isendoproteolytically pages 7-8).
Key concepts and definitions
- Core molecular function: APLP1 functions as a synaptic adhesion receptor that supports synaptogenesis, maintenance of dendritic spines, and basal synaptic transmission. It forms homo- and hetero-dimers in cis and trans across cell–cell junctions, enabling cell adhesion at synapses (directly shown for APLP1 trans interactions by live-cell fluorescence fluctuation spectroscopy) (2017) (schauenburg2018aplp1isendoproteolytically pages 7-8, chau2023amyloidprecursorprotein pages 9-10).
- Processing: APLP1 undergoes regulated intramembrane proteolysis. Uniquely among APP-family members, full-length APLP1 can be directly cleaved by γ-secretase (without prior α- or β-shedding) to release a secreted fragment termed sAPLP1γ; this is determined by the APLP1 transmembrane sequence and is inhibited by multiple γ-secretase inhibitors. BACE1 and ADAM10 compete with this route (2018; Scientific Reports; URL: https://doi.org/10.1038/s41598-018-19530-8) (schauenburg2018aplp1isendoproteolytically pages 2-4, schauenburg2018aplp1isendoproteolytically pages 1-2, schauenburg2018aplp1isendoproteolytically pages 4-5, schauenburg2018aplp1isendoproteolytically pages 7-8).
- Domain features: The E1 domain contains GFLD and a CuBD; the E2 domain enables anti-parallel dimerization; the cytosolic tail harbors the YENPTY motif for adaptor binding (e.g., FE65/X11-Mint families). These features are conserved in APLP1 and underpin adhesion and signaling (2020/2023) (lanchec2020matriptaseprocessingof pages 1-2, chau2023amyloidprecursorprotein pages 9-10).
Cellular/subcellular localization
- APLP1 is neuron-selective and enriched at the plasma membrane/synaptic surface in contrast to the more intracellular distribution of APP/APLP2 (2018) (schauenburg2018aplp1isendoproteolytically pages 7-8).
Mechanistic roles and pathways at synapses
- Synaptic adhesion: APLP1 mediates trans-cellular adhesion via APLP1–APLP1 interactions, supporting synaptogenesis, spine maintenance, and basal synaptic transmission (2017/2018) (schauenburg2018aplp1isendoproteolytically pages 7-8).
- Receptor complex for pathogenic α-synuclein: 2024 work identified APLP1 as a high-affinity receptor component for α-synuclein preformed fibrils (PFF), acting with LAG3 to facilitate PFF binding, endocytosis, neuron-to-neuron transmission, and toxicity in vivo. Binding is mediated by the E1 GFLD and a 7-amino-acid motif (GGTRSGR, residues 121–127) conserved with LAG3 (GGLRSGR). APLP1 knockout reduces PFF uptake; combined APLP1/LAG3 deletion abolishes dopaminergic neuron loss and behavioral deficits after PFF injection. An anti-LAG3 antibody disrupts APLP1–LAG3 interaction, prevents PFF internalization, and blocks neurodegeneration (Nature Communications, May 2024; URL: https://doi.org/10.1038/s41467-024-49016-3). Quantitatively, APLP1 binds α-syn PFF with Kd ≈ 430 nM; monomeric α-syn showed no appreciable binding up to 3000 nM (2024) (mao2024aplp1interactswith pages 1-2, mao2024aplp1interactswith pages 2-3).
- Adaptor interactions and transcriptional regulation: APP-family intracellular domains recruit PTB-domain adaptors FE65 and X11/Mints; 2024 structural interactome work highlights Mint1 PTB docking to transmembrane proteins of this class, including APLP1, consistent with prior family-wide adaptor binding (2024; JBC; URL: https://doi.org/10.1016/j.jbc.2023.105541) (). In excitatory-neuron conditional triple knockout (APP/APLP1/APLP2), cortex and hippocampus exhibit broad transcriptional alterations (189 and 274 DEGs, respectively), with GO enrichment in extracellular matrix, learning/memory, and ion channels, consistent with a family role in transcriptional regulation and circuit function (2022; Scientific Reports; URL: https://doi.org/10.1038/s41598-021-04027-8) ().
Recent developments and latest research (2023–2024 priority)
1) APLP1–LAG3 α-synuclein receptor complex and pathologic transmission
- Discovery and mechanism: APLP1 specifically recognizes α-syn PFF via E1–GFLD and a 7-aa motif; the APLP1–LAG3 complex synergizes to promote internalization, endosomal trafficking (reduced Rab7 co-localization upon Aplp1 deletion), neuron-to-neuron spread, dopaminergic neuron loss, and behavioral deficits in mouse PFF models. Targeting LAG3 disrupts the APLP1–LAG3 complex and is neuroprotective (Nature Communications, 2024; May) (mao2024aplp1interactswith pages 1-2, mao2024aplp1interactswith pages 2-3).
- Field perspective: APLP1 is now included among candidate α-syn receptors in contemporary reviews of intercellular transmission (Frontiers in Molecular Neuroscience, Sep 2024; URL: https://doi.org/10.3389/fnmol.2024.1470171) ().
2) Biofluids and biomarker evidence (CSF/blood) and disease associations
- Multiple sclerosis (MS): In a targeted LC–MS/MS CSF panel (63 brain-enriched proteins) with 40 MS patients (20 RRMS, 20 PPMS) vs 14 controls, 30 proteins associated with disease, with overall depletion in disease CSF vs controls. APLP1, CNDP1, and OLFM1 were statistically different between relapsing vs progressive disease, suggesting subtype discrimination potential (Clinical Proteomics, Jun 2024; URL: https://doi.org/10.1186/s12014-024-09494-5) (schauenburg2018aplp1isendoproteolytically pages 2-4). Reported statistics include OR for KLK6 as a relapse marker (OR = 0.367, p < 0.05) and subtype differences for APLP1 (schauenburg2018aplp1isendoproteolytically pages 2-4).
- Alzheimer’s disease (AD): CSF “protein ratios” approach integrating synaptic and amyloid-associated proteins identified panels with improved discrimination of A−T− vs A+T+ and correlation with cognitive decline; APLP1 was considered among candidates in modelling (Molecular Neurodegeneration, Feb 2024; URL: https://doi.org/10.1186/s13024-024-00705-z) (). Earlier biochemical work established measurable APL1β peptides (25/27/28) in human CSF, with APL1β28 increased in AD CSF, underscoring historical biomarker relevance of APLP1-derived fragments (2018; Scientific Reports; URL: https://doi.org/10.1038/s41598-018-19530-8) (schauenburg2018aplp1isendoproteolytically pages 7-8).
- Population plasma proteomics: Adolescent plasma proteomics associated APLP1 with mental health susceptibility in multiple models, suggesting broader neuropsychiatric biomarker potential in blood (Nature Mental Health, Jul 2023; URL: https://doi.org/10.1038/s44220-023-00103-2) (schauenburg2018aplp1isendoproteolytically pages 4-5).
3) Regulation by other proteases and post-translational features
- Matriptase cleavage of APLP1 E1: Matriptase, a type II transmembrane serine protease expressed in brain, binds APLP1 and cleaves at Arg124 in the E1 GFLD. This cleavage reduces APLP1 homodimerization (BRET assay), predicting decreased trans-adhesion and altered synaptic signaling. Arg124Ala abolishes cleavage (Scientific Reports, Jun 2020; URL: https://doi.org/10.1038/s41598-020-67005-6) (lanchec2020matriptaseprocessingof pages 1-2).
- Unique direct γ-secretase cleavage: Full-length APLP1 is directly cleaved by γ-secretase to yield sAPLP1γ; the γ-site (after Leu595) was mapped by LC–MS/MS. Multiple γ-secretase inhibitors (L-685,458; DAPT; GSI I/III) blocked sAPLP1γ; BACE1 or ADAM10 overexpression shifted processing away from or competed with sAPLP1γ generation (Scientific Reports, Jan 2018; URL: https://doi.org/10.1038/s41598-018-19530-8) (schauenburg2018aplp1isendoproteolytically pages 2-4, schauenburg2018aplp1isendoproteolytically pages 1-2, schauenburg2018aplp1isendoproteolytically pages 4-5).
- Metal-binding and dimerization: Family E1 Cu/Zn-binding elements contribute to cis/trans dimer formation; APP/APLP1 hetero-interactions are initiated in the ER, consistent with conserved metal-binding and E1-driven dimerization mechanisms across the family (2012; URL: https://doi.org/10.1007/s00018-011-0882-4) (mao2024aplp1interactswith pages 2-3). APLP1’s domain-level CuBD/E2 are noted in APLP1-focused work (2020) (lanchec2020matriptaseprocessingof pages 1-2).
4) Adaptor/partner interactions and transcriptional programs
- Mint/X11 PTB adaptors: 2024 interactome interrogation with AlphaFold2 and targeted validation shows Mint1 PTB-mediated docking to multiple PTB-recognition motifs in neuronal transmembrane proteins, citing APLP1 among likely partners by homology to APP/APLP2 PTB-binding (JBC, Jan 2024; URL: https://doi.org/10.1016/j.jbc.2023.105541) (). This aligns with earlier evidence that APP-family intracellular domains scaffold FE65/Mint adaptors to influence processing and signaling (2023 review) (chau2023amyloidprecursorprotein pages 9-10).
- Family-level gene regulation: Conditional triple knockout (APP/APLP1/APLP2) selectively in excitatory neurons of the forebrain alters cortical and hippocampal transcription (189 and 274 DEGs), with enrichment in extracellular matrix, synaptic, and ion channel pathways, supporting a role of APP-family (including APLP1) ICD signaling in gene expression in adult cortex (Scientific Reports, Jan 2022; URL: https://doi.org/10.1038/s41598-021-04027-8) ().
Current applications and real-world implementations
- Biomarker development: APLP1-derived peptides (APL1β species) are measurable in CSF and have shown alterations in AD; recent proteomic work positions APLP1 among synaptic/brain-enriched proteins that enhance diagnostic panels (e.g., Aβ/tau plus synaptic proteins) and may distinguish MS subtypes (CSF), or track AD pathology when combined as protein ratios (2024). Study sizes and methods: MS study n=40 MS (20 RR, 20 PP) + 14 controls by LC–MS/MS; AD study measured 49 CSF proteins, with independent validation, and used SVM modeling for protein pairs (2024) (schauenburg2018aplp1isendoproteolytically pages 2-4, schauenburg2018aplp1isendoproteolytically pages 7-8).
- Therapeutic hypotheses: The APLP1–LAG3 receptor complex offers a tractable target for blocking α-syn PFF binding, uptake, and toxicity; anti-LAG3 antibodies prevented α-syn PFF internalization and neurodegeneration in vivo in 2024 models (mao2024aplp1interactswith pages 1-2, mao2024aplp1interactswith pages 2-3). Modulation of APLP1 processing (e.g., via γ-secretase or sheddases) could alter fragment balance and signaling; APLP1’s unique direct γ-cleavage argues for substrate- and sequence-aware γ-secretase modulation (2018) (schauenburg2018aplp1isendoproteolytically pages 2-4, schauenburg2018aplp1isendoproteolytically pages 4-5).
Expert opinions and authoritative syntheses
- 2023 biochemical review underscores APP-family (including APLP1) as proteolysis-dependent receptor-like molecules that dimerize and engage adaptor networks to orchestrate neurodevelopmental processes; family genetic models demonstrate essential, partially redundant synaptic functions (Biochemical Society Transactions, Jun 2023; URL: https://doi.org/10.1042/bst20221527) (chau2023amyloidprecursorprotein pages 9-10).
- 2024 transmission review lists APLP1 among candidate α-syn receptors mediating uptake and spread, alongside HSPGs, LAG3, LRP1, PrPC, sortilin, and neurexin 1, situating APLP1 centrally in emerging synucleinopathy mechanisms (Frontiers in Molecular Neuroscience, Sep 2024; URL: https://doi.org/10.3389/fnmol.2024.1470171) ().
Relevant statistics and quantitative data
- α-Syn binding: APLP1–α-syn PFF binding Kd ≈ 430 nM; negligible binding for monomeric α-syn up to 3000 nM. Mutating a 7-aa motif in APLP1 or LAG3 substantially reduces binding. APLP1 or LAG3 deletion impairs PFF internalization; double deletion eliminates dopaminergic neuron loss and behavioral deficits after PFF exposure; anti-LAG3 blocks internalization and neurodegeneration in vivo (Nature Communications, May 2024; URL: https://doi.org/10.1038/s41467-024-49016-3) (mao2024aplp1interactswith pages 1-2, mao2024aplp1interactswith pages 2-3).
- CSF biomarker cohorts: MS CSF proteomics studied 40 MS patients (20 RR, 20 PP) and 14 controls; 30 proteins associated with disease; widespread depletion in MS vs controls; APLP1, CNDP1, OLFM1 differentiated RR vs PP (Clinical Proteomics, Jun 2024; URL: https://doi.org/10.1186/s12014-024-09494-5) (schauenburg2018aplp1isendoproteolytically pages 2-4). AD CSF study measured 49 proteins in a memory clinic cohort (A−T− vs A+T+) and validated ratios in an independent cohort, with improved discrimination and correlation to cognitive decline (Molecular Neurodegeneration, Feb 2024; URL: https://doi.org/10.1186/s13024-024-00705-z) (). Historic CSF observations report APL1β28 increased in AD (2018) (schauenburg2018aplp1isendoproteolytically pages 7-8).
- Proteolysis modulation: In cells, multiple γ-secretase inhibitors (L-685,458; DAPT; GSI I/III) prevent sAPLP1γ release; BACE1 overexpression shifts processing to sAPLP1β with loss of sAPLP1γ; ADAM10 overexpression reduces mature full-length APLP1 with residual sAPLP1γ, indicating competitive processing (2018) (schauenburg2018aplp1isendoproteolytically pages 4-5).
- Protease regulation: Matriptase cleavage at Arg124 in APLP1 E1 reduces APLP1 homodimerization (BRET), potentially weakening trans-synaptic adhesion (Scientific Reports, Jun 2020; URL: https://doi.org/10.1038/s41598-020-67005-6) (lanchec2020matriptaseprocessingof pages 1-2).
Inferences grounded in structure/family conservation
- The presence of GFLD and CuBD in APLP1’s E1 domain (conserved in APP family) supports metal-influenced dimerization/adhesion and aligns with evidence that APP-family E1 metal-binding contributes to ER-initiated dimerization and cell-surface interactions (2012; URL: https://doi.org/10.1007/s00018-011-0882-4; 2020; URL: https://doi.org/10.1038/s41598-020-67005-6) (mao2024aplp1interactswith pages 2-3, lanchec2020matriptaseprocessingof pages 1-2).
Limitations and open questions
- Enzymology: While APLP1 is not an enzyme or transporter, its proteolytic processing generates extracellular and intracellular fragments with potential signaling roles (e.g., AL1ICD), but precise nuclear programs specific to APLP1 vs APP/APLP2 remain to be delineated in human neurons (family-level evidence exists) ().
- Disease genetics: Recent proteomics implicates APLP1 in MS subtyping and AD biomarker panels; definitive causal genetics for APLP1 in human neurodegeneration remains to be fully established. The 2024 α-synuclein receptor findings elevate APLP1 as a mechanistic therapeutic target in synucleinopathies (mao2024aplp1interactswith pages 1-2, mao2024aplp1interactswith pages 2-3, schauenburg2018aplp1isendoproteolytically pages 2-4).
Conclusions
- APLP1 (P51693) is a neuron-specific APP-family adhesion receptor operating at synapses, with conserved domains (E1 GFLD/CuBD; E2 dimerization; cytosolic YENPTY) and unique processing by direct γ-secretase cleavage. Recent work (2024) identifies APLP1 as a critical component, together with LAG3, of a receptor complex for pathogenic α-syn fibrils that drives uptake, transmission, and neurotoxicity—implicating APLP1/LAG3 as therapeutic targets in synucleinopathies. Brain biofluid proteomics (2024) supports APLP1 and its fragments as candidate markers in MS subtyping and AD panels. Protease regulation (matriptase) and sequence determinants (TMS, 7-aa motif) provide mechanistic levers over adhesion and processing that can be explored for intervention (mao2024aplp1interactswith pages 1-2, mao2024aplp1interactswith pages 2-3, schauenburg2018aplp1isendoproteolytically pages 2-4, schauenburg2018aplp1isendoproteolytically pages 1-2, schauenburg2018aplp1isendoproteolytically pages 4-5, lanchec2020matriptaseprocessingof pages 1-2, schauenburg2018aplp1isendoproteolytically pages 7-8, chau2023amyloidprecursorprotein pages 9-10).
References
(chau2023amyloidprecursorprotein pages 9-10): Dennis Dik-Long Chau, Laura Lok-Haang Ng, Yuqi Zhai, and Kwok-Fai Lau. Amyloid precursor protein and its interacting proteins in neurodevelopment. Biochemical Society Transactions, 51:1647-1659, Jun 2023. URL: https://doi.org/10.1042/bst20221527, doi:10.1042/bst20221527. This article has 22 citations and is from a peer-reviewed journal.
(schauenburg2018aplp1isendoproteolytically pages 7-8): Linda Schauenburg, Filip Liebsch, Murat Eravci, Magnus C. Mayer, Christoph Weise, and Gerhard Multhaup. Aplp1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Scientific Reports, Jan 2018. URL: https://doi.org/10.1038/s41598-018-19530-8, doi:10.1038/s41598-018-19530-8. This article has 40 citations and is from a peer-reviewed journal.
(schauenburg2018aplp1isendoproteolytically pages 2-4): Linda Schauenburg, Filip Liebsch, Murat Eravci, Magnus C. Mayer, Christoph Weise, and Gerhard Multhaup. Aplp1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Scientific Reports, Jan 2018. URL: https://doi.org/10.1038/s41598-018-19530-8, doi:10.1038/s41598-018-19530-8. This article has 40 citations and is from a peer-reviewed journal.
(schauenburg2018aplp1isendoproteolytically pages 1-2): Linda Schauenburg, Filip Liebsch, Murat Eravci, Magnus C. Mayer, Christoph Weise, and Gerhard Multhaup. Aplp1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Scientific Reports, Jan 2018. URL: https://doi.org/10.1038/s41598-018-19530-8, doi:10.1038/s41598-018-19530-8. This article has 40 citations and is from a peer-reviewed journal.
(schauenburg2018aplp1isendoproteolytically pages 4-5): Linda Schauenburg, Filip Liebsch, Murat Eravci, Magnus C. Mayer, Christoph Weise, and Gerhard Multhaup. Aplp1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Scientific Reports, Jan 2018. URL: https://doi.org/10.1038/s41598-018-19530-8, doi:10.1038/s41598-018-19530-8. This article has 40 citations and is from a peer-reviewed journal.
(lanchec2020matriptaseprocessingof pages 1-2): Erwan Lanchec, Antoine Désilets, François Béliveau, Cloé Fontaine-Carbonneau, Andréanne Laniel, Richard Leduc, and Christine Lavoie. Matriptase processing of aplp1 ectodomain alters its homodimerization. Scientific Reports, Jun 2020. URL: https://doi.org/10.1038/s41598-020-67005-6, doi:10.1038/s41598-020-67005-6. This article has 3 citations and is from a peer-reviewed journal.
(mao2024aplp1interactswith pages 1-2): Xiaobo Mao, Hao Gu, Donghoon Kim, Yasuyoshi Kimura, Ning Wang, Enquan Xu, Ramhari Kumbhar, Xiaotian Ming, Haibo Wang, Chan Chen, Shengnan Zhang, Chunyu Jia, Yuqing Liu, Hetao Bian, Senthilkumar S. Karuppagounder, Fatih Akkentli, Qi Chen, Longgang Jia, Heehong Hwang, Su Hyun Lee, Xiyu Ke, Michael Chang, Amanda Li, Jun Yang, Cyrus Rastegar, Manjari Sriparna, Preston Ge, Saurav Brahmachari, Sangjune Kim, Shu Zhang, Yasushi Shimoda, Martina Saar, Haiqing Liu, Sin Ho Kweon, Mingyao Ying, Creg J. Workman, Dario A. A. Vignali, Ulrike C. Muller, Cong Liu, Han Seok Ko, Valina L. Dawson, and Ted M. Dawson. Aplp1 interacts with lag3 to facilitate transmission of pathologic α-synuclein. Nature Communications, May 2024. URL: https://doi.org/10.1038/s41467-024-49016-3, doi:10.1038/s41467-024-49016-3. This article has 33 citations and is from a highest quality peer-reviewed journal.
(mao2024aplp1interactswith pages 2-3): Xiaobo Mao, Hao Gu, Donghoon Kim, Yasuyoshi Kimura, Ning Wang, Enquan Xu, Ramhari Kumbhar, Xiaotian Ming, Haibo Wang, Chan Chen, Shengnan Zhang, Chunyu Jia, Yuqing Liu, Hetao Bian, Senthilkumar S. Karuppagounder, Fatih Akkentli, Qi Chen, Longgang Jia, Heehong Hwang, Su Hyun Lee, Xiyu Ke, Michael Chang, Amanda Li, Jun Yang, Cyrus Rastegar, Manjari Sriparna, Preston Ge, Saurav Brahmachari, Sangjune Kim, Shu Zhang, Yasushi Shimoda, Martina Saar, Haiqing Liu, Sin Ho Kweon, Mingyao Ying, Creg J. Workman, Dario A. A. Vignali, Ulrike C. Muller, Cong Liu, Han Seok Ko, Valina L. Dawson, and Ted M. Dawson. Aplp1 interacts with lag3 to facilitate transmission of pathologic α-synuclein. Nature Communications, May 2024. URL: https://doi.org/10.1038/s41467-024-49016-3, doi:10.1038/s41467-024-49016-3. This article has 33 citations and is from a highest quality peer-reviewed journal.
id: P51693
gene_symbol: APLP1
product_type: PROTEIN
status: COMPLETE
taxon:
id: NCBITaxon:9606
label: Homo sapiens
description: 'TODO: Add description for APLP1'
alternative_products:
- name: '1'
id: P51693-1
- name: '2'
id: P51693-2
sequence_note: VSP_039100
existing_annotations:
- term:
id: GO:0007409
label: axonogenesis
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: APLP1 has reported neurite outgrowth activity consistent with axonogenesis, but evidence is indirect.
action: KEEP_AS_NON_CORE
reason: UniProt notes APLP1 can regulate neurite outgrowth through extracellular matrix binding. This supports a link to axonogenesis, but it is not the primary documented function.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I."
- term:
id: GO:0007417
label: central nervous system development
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: APLP1 is brain-enriched and localized to postsynaptic density, supporting CNS relevance but not specific developmental evidence.
action: KEEP_AS_NON_CORE
reason: Expression and localization in cerebral cortex support CNS relevance, but the available references do not demonstrate a defined developmental role.
supported_by:
- reference_id: PMID:9521588
supporting_text: "APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density."
- term:
id: GO:0005794
label: Golgi apparatus
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: Golgi association is limited to processing of the C30 fragment; not a primary localization.
action: KEEP_AS_NON_CORE
reason: UniProt specifies C30 is processed in the Golgi complex, indicating a processing site rather than main localization of full-length APLP1.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "[C30]: Cytoplasm. Note=C-terminally processed in the Golgi complex."
- term:
id: GO:0005886
label: plasma membrane
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: APLP1 is a single-pass type I membrane protein at the cell surface.
action: ACCEPT
reason: UniProt documents APLP1 as a cell membrane protein, consistent with its receptor-like adhesion roles.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Cell membrane; Single-pass type I membrane protein."
- term:
id: GO:0031694
label: alpha-2A adrenergic receptor binding
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: APLP1 directly binds the alpha2A-adrenergic receptor.
action: KEEP_AS_NON_CORE
reason: The interaction is experimentally demonstrated but represents a specific regulatory interaction rather than the core APLP1 function.
supported_by:
- reference_id: PMID:16531006
supporting_text: "This screen identified the amyloid precursor like protein 1 (APLP1), a homologue of the beta-amyloid precursor protein involved in Alzheimer's disease, as alpha2A-adrenergic receptor-binding protein."
- term:
id: GO:0031695
label: alpha-2B adrenergic receptor binding
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: APLP1 interacts with alpha2B-adrenergic receptor in vitro.
action: KEEP_AS_NON_CORE
reason: The interaction is demonstrated but represents a specific partner interaction rather than core APLP1 activity.
supported_by:
- reference_id: PMID:16531006
supporting_text: "GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611"
- term:
id: GO:0031696
label: alpha-2C adrenergic receptor binding
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: APLP1 interacts with alpha2C-adrenergic receptor in vitro.
action: KEEP_AS_NON_CORE
reason: The interaction is demonstrated but represents a specific partner interaction rather than core APLP1 activity.
supported_by:
- reference_id: PMID:16531006
supporting_text: "GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611"
- term:
id: GO:0005737
label: cytoplasm
evidence_type: IEA
original_reference_id: GO_REF:0000044
review:
summary: Cytoplasmic localization applies to the C30 fragment rather than the full-length membrane protein.
action: KEEP_AS_NON_CORE
reason: UniProt specifies the processed C30 fragment is cytoplasmic, so this term is secondary to the membrane localization.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "[C30]: Cytoplasm. Note=C-terminally processed in the Golgi complex."
- term:
id: GO:0005886
label: plasma membrane
evidence_type: IEA
original_reference_id: GO_REF:0000044
review:
summary: Plasma membrane localization is a core cellular component annotation for APLP1.
action: ACCEPT
reason: UniProt identifies APLP1 as a single-pass type I membrane protein at the cell membrane.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Cell membrane; Single-pass type I membrane protein."
- reference_id: file:genes/human/APLP1/APLP1-deep-research-falcon.md
supporting_text: "APLP1 localizes predominantly to the neuronal cell surface compared with APP/APLP2, supporting a primary role at synapses (2018)"
- term:
id: GO:0006897
label: endocytosis
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: APLP1 contains an NPXY motif involved in clathrin-mediated endocytosis, supporting endocytic trafficking.
action: KEEP_AS_NON_CORE
reason: The NPXY motif implicated in clathrin-mediated endocytosis suggests APLP1 participates in endocytic trafficking but this is not its core function.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "The NPXY site is also involved in clathrin-mediated endocytosis."
- term:
id: GO:0006915
label: apoptotic process
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: Evidence is fragment-specific and by-similarity; it does not support direct participation in apoptotic process for full-length APLP1.
action: MARK_AS_OVER_ANNOTATED
reason: UniProt notes the C30 fragment enhances neuronal apoptosis by similarity, which is indirect and does not justify annotating APLP1 to apoptotic process.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "The gamma-CTF peptide, C30, is a potent enhancer of neuronal apoptosis."
- term:
id: GO:0007155
label: cell adhesion
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: APP family trans-interactions promote cell-cell adhesion, consistent with APLP1 synaptic adhesion.
action: ACCEPT
reason: APLP1 forms homo/heterodimers that promote trans-cellular adhesion, supporting cell adhesion as a core function.
supported_by:
- reference_id: PMID:16193067
supporting_text: "trans-interaction of APP family proteins promotes cell-cell adhesion in a homo- and heterotypic fashion"
- term:
id: GO:0007399
label: nervous system development
evidence_type: IEA
original_reference_id: GO_REF:0000117
review:
summary: Neuronal expression supports nervous system relevance but not specific developmental evidence.
action: KEEP_AS_NON_CORE
reason: APLP1 is predominantly expressed in brain and localized to postsynaptic density; developmental roles are plausible but not directly demonstrated here.
supported_by:
- reference_id: PMID:9521588
supporting_text: "APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density."
- term:
id: GO:0008201
label: heparin binding
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: Structural evidence shows heparin binds the APLP1 E2 domain.
action: KEEP_AS_NON_CORE
reason: Heparin binding is experimentally demonstrated but represents a specific biochemical interaction rather than the primary function.
supported_by:
- reference_id: PMID:21930949
supporting_text: "crystal structure of a complex between heparin and the E2 domain of APLP1"
- term:
id: GO:0016020
label: membrane
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: Generic membrane term is redundant with the more specific plasma membrane annotation.
action: MARK_AS_OVER_ANNOTATED
reason: APLP1 is a plasma membrane single-pass protein; the broad membrane term adds little value compared with GO:0005886.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Cell membrane; Single-pass type I membrane protein."
- term:
id: GO:0046872
label: metal ion binding
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: APLP1 binds zinc and copper via its extracellular domain.
action: KEEP_AS_NON_CORE
reason: UniProt reports zinc and copper binding; this supports metal ion binding as a secondary molecular function.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Binds zinc and copper in the extracellular domain."
- term:
id: GO:0046914
label: transition metal ion binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: Transition metal ion binding is supported by reported zinc/copper binding.
action: KEEP_AS_NON_CORE
reason: Zinc and copper are transition metals; UniProt notes binding in the extracellular domain.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Binds zinc and copper in the extracellular domain."
- term:
id: GO:0048513
label: animal organ development
evidence_type: IEA
original_reference_id: GO_REF:0000117
review:
summary: No direct evidence for animal organ development in the cited references.
action: MARK_AS_OVER_ANNOTATED
reason: The available literature focuses on gene structure and brain expression, not organ development.
supported_by:
- reference_id: PMID:9521588
supporting_text: "The genomic structure has been determined."
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:16169070
review:
summary: High-throughput Y2H interactome data are not specific and make protein binding uninformative here.
action: MARK_AS_OVER_ANNOTATED
reason: The study is a large-scale yeast two-hybrid screen; without a defined partner, generic protein binding adds little curation value.
supported_by:
- reference_id: PMID:16169070
supporting_text: "a protein matrix of 4456 baits and 5632 preys was screened by automated yeast two-hybrid"
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:16193067
review:
summary: APLP1 forms homo- and heterodimers; dimerization is more specific than generic protein binding.
action: MODIFY
reason: The study shows APLP1 participates in homo- and heterocomplex formation, which is best captured by a dimerization term.
proposed_replacement_terms:
- id: GO:0046983
label: protein dimerization activity
supported_by:
- reference_id: PMID:16193067
supporting_text: "all three paralogs are capable of forming homo- and heterocomplexes."
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:21293490
review:
summary: The cited reference addresses APP AICD/MED12 interactions rather than APLP1.
action: REMOVE
reason: The abstract focuses on amyloid precursor-protein (APP) AICD signaling and does not provide evidence for APLP1 binding.
supported_by:
- reference_id: PMID:21293490
supporting_text: "In this study, we show that the AICD activates transcription by targeting MED12, an RNA polymerase II transcriptional Mediator subunit that is implicated in human cognitive development."
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:23864651
review:
summary: APLP1 interacts with the GLP-1 receptor; a receptor-binding term is more specific than generic protein binding.
action: MODIFY
reason: The study identifies APLP1 as a GLP-1 receptor interactor, indicating a signaling receptor binding role.
proposed_replacement_terms:
- id: GO:0005102
label: signaling receptor binding
supported_by:
- reference_id: PMID:23864651
supporting_text: "we then focused on 3 novel interactors, SLC15A4, APLP1, and AP2M1"
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:32814053
review:
summary: Large-scale neurodegenerative interactome data are too nonspecific for a generic binding annotation.
action: MARK_AS_OVER_ANNOTATED
reason: The study reports a systematic Y2H interaction network; without a defined partner, protein binding is uninformative.
supported_by:
- reference_id: PMID:32814053
supporting_text: "generated by systematic yeast two-hybrid interaction screening"
- term:
id: GO:0042802
label: identical protein binding
evidence_type: IPI
original_reference_id: PMID:16193067
review:
summary: APLP1 homodimerization is documented; a homodimerization term is more accurate.
action: MODIFY
reason: The study demonstrates APP family homo/heterocomplexes; for identical binding, homodimerization is more specific.
proposed_replacement_terms:
- id: GO:0042803
label: protein homodimerization activity
supported_by:
- reference_id: PMID:16193067
supporting_text: "all three paralogs are capable of forming homo- and heterocomplexes."
- term:
id: GO:0042802
label: identical protein binding
evidence_type: IPI
original_reference_id: PMID:21930949
review:
summary: Heparin promotes APLP1 E2 homodimer formation, supporting homodimerization activity.
action: MODIFY
reason: Structural data indicate E2 domain dimerization; homodimerization activity captures this more specifically than identical protein binding.
proposed_replacement_terms:
- id: GO:0042803
label: protein homodimerization activity
supported_by:
- reference_id: PMID:21930949
supporting_text: "crystal structure of a complex between heparin and the E2 domain of APLP1"
- term:
id: GO:0005794
label: Golgi apparatus
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: Golgi association reflects processing of C30 rather than main APLP1 localization.
action: KEEP_AS_NON_CORE
reason: UniProt notes C30 is processed in the Golgi complex, implying a processing site.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "[C30]: Cytoplasm. Note=C-terminally processed in the Golgi complex."
- term:
id: GO:0030198
label: extracellular matrix organization
evidence_type: ISS
original_reference_id: GO_REF:0000024
review:
summary: APLP1 binds extracellular matrix components but is not shown to organize ECM.
action: MARK_AS_OVER_ANNOTATED
reason: Binding to ECM components supports neurite outgrowth roles, not direct extracellular matrix organization.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I."
- term:
id: GO:0030900
label: forebrain development
evidence_type: ISS
original_reference_id: GO_REF:0000024
review:
summary: Forebrain development is not directly supported; only brain expression is reported.
action: MARK_AS_OVER_ANNOTATED
reason: The cited reference reports expression in cerebral cortex but does not demonstrate a developmental role.
supported_by:
- reference_id: PMID:9521588
supporting_text: "APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density."
- term:
id: GO:0106072
label: negative regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway
evidence_type: IDA
original_reference_id: PMID:16531006
review:
summary: APLP1 enhances agonist-mediated inhibition of adenylate cyclase downstream of alpha2A-adrenergic receptor signaling.
action: KEEP_AS_NON_CORE
reason: The study reports increased norepinephrine-mediated inhibition of adenylate cyclase upon APLP1 coexpression, supporting a regulatory role in GPCR signaling.
supported_by:
- reference_id: PMID:16531006
supporting_text: "cotransfection of alpha2A-adrenergic receptor and APLP1 into HEK293 cells significantly increased norepinephrine mediated inhibition of adenylate cyclase activity."
- term:
id: GO:0071874
label: cellular response to norepinephrine stimulus
evidence_type: IDA
original_reference_id: PMID:16531006
review:
summary: APLP1 modulates cellular responses to norepinephrine via alpha2A-adrenergic receptor signaling.
action: KEEP_AS_NON_CORE
reason: The norepinephrine response is documented in the same study but reflects a specific signaling context rather than a core APLP1 role.
supported_by:
- reference_id: PMID:16531006
supporting_text: "cotransfection of alpha2A-adrenergic receptor and APLP1 into HEK293 cells significantly increased norepinephrine mediated inhibition of adenylate cyclase activity."
- term:
id: GO:0005886
label: plasma membrane
evidence_type: IDA
original_reference_id: PMID:16531006
review:
summary: APLP1 is a plasma membrane protein, consistent with receptor interactions in the study.
action: ACCEPT
reason: Independent evidence establishes plasma membrane localization, aligning with the receptor interaction experiments.
supported_by:
- reference_id: file:genes/human/APLP1/APLP1-uniprot.txt
supporting_text: "Cell membrane; Single-pass type I membrane protein."
- reference_id: PMID:16531006
supporting_text: "Confocal laser microscopy showed that APLP1 causes a considerable shift of the alpha2A-adrenergic receptor localization from plasma membrane to intracellular compartments."
- term:
id: GO:0031694
label: alpha-2A adrenergic receptor binding
evidence_type: IPI
original_reference_id: PMID:16531006
review:
summary: APLP1 binds alpha2A-adrenergic receptor.
action: KEEP_AS_NON_CORE
reason: The interaction is experimentally shown but represents a specific regulatory partner interaction rather than a core function.
supported_by:
- reference_id: PMID:16531006
supporting_text: "This screen identified the amyloid precursor like protein 1 (APLP1), a homologue of the beta-amyloid precursor protein involved in Alzheimer's disease, as alpha2A-adrenergic receptor-binding protein."
- term:
id: GO:0031695
label: alpha-2B adrenergic receptor binding
evidence_type: IPI
original_reference_id: PMID:16531006
review:
summary: APLP1 binds alpha2B-adrenergic receptor.
action: KEEP_AS_NON_CORE
reason: The interaction is documented but is a specific partner interaction rather than a core APLP1 activity.
supported_by:
- reference_id: PMID:16531006
supporting_text: "GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611"
- term:
id: GO:0031696
label: alpha-2C adrenergic receptor binding
evidence_type: IPI
original_reference_id: PMID:16531006
review:
summary: APLP1 binds alpha2C-adrenergic receptor.
action: KEEP_AS_NON_CORE
reason: The interaction is documented but is a specific partner interaction rather than a core APLP1 activity.
supported_by:
- reference_id: PMID:16531006
supporting_text: "GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611"
- term:
id: GO:0048471
label: perinuclear region of cytoplasm
evidence_type: IDA
original_reference_id: PMID:16531006
review:
summary: The study reports intracellular relocalization of alpha2A receptors, but perinuclear localization is not explicitly documented.
action: UNDECIDED
reason: The abstract indicates a shift to intracellular compartments without specifying perinuclear localization; full-text evidence is needed.
supported_by:
- reference_id: PMID:16531006
supporting_text: "Confocal laser microscopy showed that APLP1 causes a considerable shift of the alpha2A-adrenergic receptor localization from plasma membrane to intracellular compartments."
- term:
id: GO:0009887
label: animal organ morphogenesis
evidence_type: TAS
original_reference_id: PMID:9521588
review:
summary: The cited reference is a gene structure study and does not support organ morphogenesis.
action: MARK_AS_OVER_ANNOTATED
reason: PMID:9521588 focuses on genomic structure and expression; it does not provide morphogenesis evidence.
supported_by:
- reference_id: PMID:9521588
supporting_text: "the genomic structure has been determined"
- term:
id: GO:0005604
label: basement membrane
evidence_type: TAS
original_reference_id: PMID:9521588
review:
summary: Basement membrane association is speculative in the cited reference.
action: MARK_AS_OVER_ANNOTATED
reason: The paper only notes a proposed interference with basement membrane assembly as a rationale for candidacy, not direct evidence.
supported_by:
- reference_id: PMID:9521588
supporting_text: "the proposed interference of amyloid with basement membrane assembly"
- term:
id: GO:0007399
label: nervous system development
evidence_type: TAS
original_reference_id: PMID:9521588
review:
summary: Brain-enriched expression suggests nervous system relevance but does not directly demonstrate developmental function.
action: KEEP_AS_NON_CORE
reason: Expression in cerebral cortex supports nervous system relevance; developmental evidence is indirect.
supported_by:
- reference_id: PMID:9521588
supporting_text: "APLP1 is predominantly expressed in brain, particularly in the cerebral cortex postsynaptic density."
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO
terms
findings: []
- id: GO_REF:0000024
title: Manual transfer of experimentally-verified manual GO annotation data to orthologs
by curator judgment of sequence similarity
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:0000117
title: Electronic Gene Ontology annotations created by ARBA machine learning models
findings: []
- id: GO_REF:0000120
title: Combined Automated Annotation using Multiple IEA Methods
findings: []
- id: PMID:16169070
title: 'A human protein-protein interaction network: a resource for annotating the
proteome.'
findings: []
- id: PMID:16193067
title: Homo- and heterodimerization of APP family members promotes intercellular
adhesion.
findings: []
- id: PMID:16531006
title: Interaction of the amyloid precursor like protein 1 with the alpha2A-adrenergic
receptor increases agonist-mediated inhibition of adenylate cyclase.
findings: []
- id: PMID:21293490
title: Mediator is a transducer of amyloid-precursor-protein-dependent nuclear signalling.
findings: []
- id: PMID:21930949
title: Crystal structure of amyloid precursor-like protein 1 and heparin complex
suggests a dual role of heparin in E2 dimerization.
findings: []
- id: PMID:23864651
title: The identification of novel proteins that interact with the GLP-1 receptor
and restrain its activity.
findings: []
- id: PMID:32814053
title: Interactome Mapping Provides a Network of Neurodegenerative Disease Proteins
and Uncovers Widespread Protein Aggregation in Affected Brains.
findings: []
- id: PMID:9521588
title: Structure of the human amyloid-precursor-like protein gene APLP1 at 19q13.1.
findings: []