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Showing ADGRL1CIRL1 is a alias.

ADGRL1

Adhesion G protein-coupled receptor L1 · UniProt O94910

Length
1474 aa
Mass
162.7 kDa
Annotated
2026-06-09
26 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ADGRL1 (Latrophilin-1) is an adhesion G-protein-coupled receptor that bridges trans-synaptic adhesion to intracellular signaling and governs synapse formation, neurotransmitter release, and systemic energy homeostasis (PMID:35907405, PMID:37712955). The receptor matures by constitutive autoproteolytic cleavage at its GPS domain in the endoplasmic reticulum, generating a non-covalent N-terminal/C-terminal fragment (NTF–CTF) heterodimer whose surface trafficking is suppressed by PKC activation (PMID:20100540). Its extracellular olfactomedin/lectin-like region mediates high-affinity, splice-site-4-regulated adhesion to neurexins lacking the SS4 insert, competing with neuroligin-1 for neurexin binding (PMID:22262843), and also engages the cytokine TAFA2 through its lectin-like domain to drive cAMP/PKA/CREB/BCL2 anti-apoptotic signaling (PMID:37944639). Specific transmembrane-domain residues control basal constitutive activity and the response to the endogenous tethered agonist peptide, with a cancer-associated TMD mutation increasing basal activity (PMID:30428326). Downstream coupling is shaped by cytoplasmic SSB alternative splicing, which dictates constitutive Gαi/o versus ligand-dependent Gαs cAMP output (PMID:31339586), and by constitutive β-arrestin recruitment at the plasma membrane and early endosomes that primes activation of all four G-protein families (PMID:41819453). Phosphorylation of the CTF stabilizes its association with the NTF, while α-latrotoxin binding recruits RPTPσ to dephosphorylate and release the CTF (PMID:31553068). ADGRL1 additionally binds glucose to mediate hypothalamic VMH glucose sensing and energy balance, with loss causing obesity and dysregulated glucose homeostasis (PMID:37712955, PMID:38664368), and its ablation activates JAK/STAT1-Decorin and disrupts GSK3β/β-catenin signaling to promote anti-tumor immunity (PMID:42172123).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 2010 Medium

    Established how ADGRL1 matures into a functional two-subunit receptor, addressing whether the receptor is processed and how its surface delivery is controlled.

    Evidence Transfection of wild-type and non-cleavable CIRL-1 mutants with PKC activator treatment and surface trafficking assays

    PMID:20100540

    Open questions at the time
    • Identity of any auxiliary factor required for GPS cleavage not defined
    • Physiological trigger linking PKC signaling to receptor downregulation unresolved
  2. 2012 High

    Defined the extracellular adhesion partner and the structural basis of partner selection, showing ADGRL1 forms a splice-regulated trans-cellular complex with neurexins.

    Evidence Saturation binding, extracellular domain deletion mapping, and co-culture cell adhesion assays

    PMID:22262843

    Open questions at the time
    • Downstream signaling consequence of neurexin adhesion not addressed in this study
    • In vivo relevance of the competition with neuroligin-1 untested
  3. 2018 High

    Mapped the transmembrane determinants of receptor activation, linking specific TMD residues to constitutive activity and tethered-agonist response.

    Evidence Comprehensive TMD mutagenesis with cell-based functional assays and transgenic C. elegans rescue

    PMID:30428326

    Open questions at the time
    • Structural mechanism by which the tethered agonist engages the TMD not resolved
    • Which G-protein outputs each residue controls not delineated
  4. 2019 Medium

    Showed that cytoplasmic SSB splicing creates signaling bias, answering how a single receptor produces divergent cAMP responses.

    Evidence cAMP competitive binding assays with pertussis toxin and SSB-containing versus SSB-deficient variants, plus Ca2+ and MAPK readouts

    PMID:31339586

    Open questions at the time
    • Structural basis of splice-dependent coupling bias unknown
    • In vivo distribution and function of the two variants not established
  5. 2019 Medium

    Connected CTF phosphorylation state to NTF–CTF heterodimer stability and to α-latrotoxin-triggered subunit dissociation, defining a regulatable activation switch.

    Evidence Affinity co-purification, sucrose gradient fractionation, and phosphorylation/α-latrotoxin analysis of synaptic preparations

    PMID:31553068

    Open questions at the time
    • Kinase responsible for CTF phosphorylation not identified
    • Functional consequence of CTF release for downstream signaling not directly measured
  6. 2022 High

    Demonstrated the in vivo neuronal role of ADGRL1, establishing it as a regulator of synapse formation and neurotransmitter release with human variant relevance.

    Evidence Human variant expression with Ca2+ assays in neuroblastoma cells, ex vivo exocytosis assays, in vitro synapse formation, and Adgrl1 knockout mice on two backgrounds

    PMID:35907405

    Open questions at the time
    • Molecular link between adhesion/coupling and exocytosis control not mechanistically resolved
    • Specific synaptic G-protein effectors not identified
  7. 2023 High

    Identified TAFA2 as a lectin-domain ligand coupling ADGRL1 to an anti-apoptotic cAMP/PKA/CREB/BCL2 program.

    Evidence Co-IP, mass spectrometry, pulldowns, KO and Lec-deletion mutants, and pathway/apoptosis readouts

    PMID:37944639

    Open questions at the time
    • G-protein identity downstream of TAFA2 not specified
    • Tissue context of TAFA2–ADGRL1 signaling beyond cell models limited
  8. 2023 High

    Revealed an unexpected metabolic function by showing ADGRL1 binds glucose and is required for hypothalamic glucose sensing and energy homeostasis.

    Evidence Glucose-binding affinity assays in CHO cells, global and hypothalamus-specific knockouts, VMH electrophysiology, and metabolic phenotyping

    PMID:37712955

    Open questions at the time
    • Structural site of glucose binding not defined
    • Signal transduction from glucose binding to VMH neuron firing not mapped
  9. 2024 Medium

    Reinforced ADGRL1 as an energy-balance regulator, linking deficiency to obesity and a partially inactivating human mutation.

    Evidence Adgrl1-deficient mouse metabolic phenotyping and human variant functional characterization

    PMID:38664368

    Open questions at the time
    • Causal chain from receptor loss to hyperphagia not resolved
    • Single human variant limits genetic generalization
  10. 2024 Medium

    Identified hevin/SPARCL1 as a ligand that biases ADGRL1 coupling and modulates adhesion and reward behavior.

    Evidence Co-IP, internalization and adhesion assays, BRET coupling assays, and NAc Adgrl1 knockdown with cocaine reward paradigms (preprint)

    PMID:bio_10.1101_2024.07.03.601736

    Open questions at the time
    • Preprint, not yet peer-reviewed
    • Direct binding domain on ADGRL1 not mapped
    • Mechanism linking coupling bias to reward behavior unresolved
  11. 2026 High

    Resolved the order of signaling events, showing β-arrestin recruitment and endosomal localization prime activation of all four G-protein families.

    Evidence G-protein BRET biosensors, β-arrestin knockdown/knockout, dynamin inhibition, endosome-targeted biosensors, and splice-variant analysis in HEK293 cells

    PMID:41819453

    Open questions at the time
    • Whether endosomal priming operates in neurons in vivo not tested
    • Structural basis of distinct βarr/G-protein complex assemblies unresolved
  12. 2026 Medium

    Connected ADGRL1 loss to anti-tumor immunity via interferon, JAK/STAT1-Decorin, and GSK3β/β-catenin pathways, opening a therapeutic avenue.

    Evidence Drosophila RNAi screen, single-cell transcriptomics, mouse KO, pathway and Decorin secretion assays, PD-1 combination, and DARTS-based compound identification

    PMID:42172123

    Open questions at the time
    • Direct molecular link between ADGRL1 and GSK3β/β-catenin not defined
    • Receptor signaling state driving the immune phenotype unclear

Open questions

Synthesis pass · forward-looking unresolved questions
  • How ADGRL1's distinct ligands (neurexins, teneurins, TAFA2, hevin, glucose) are integrated into selective G-protein and β-arrestin outputs across synaptic, metabolic, and immune contexts remains unresolved.
  • No unified structural model linking ligand identity to coupling bias
  • Tissue-specific signaling outputs not reconciled
  • In vivo significance of endosomal G-protein priming untested

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060089 molecular transducer activity 2 GO:0098772 molecular function regulator activity 2 GO:0098631 cell adhesion mediator activity 1 GO:0140096 catalytic activity, acting on a protein 1
Localization
GO:0005886 plasma membrane 2 GO:0005768 endosome 1 GO:0005783 endoplasmic reticulum 1
Pathway
R-HSA-1430728 Metabolism 2 R-HSA-162582 Signal Transduction 2 R-HSA-112316 Neuronal System 1 R-HSA-1500931 Cell-Cell communication 1
Complex memberships
NTF–CTF heterodimer

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2012 The olfactomedin-like domain of CIRL1/latrophilin-1 (ADGRL1) mediates direct, high-affinity (nanomolar) binding to neurexins lacking an insert at splice site 4 (SS4); neurexins with an SS4 insert cannot bind. This interaction is trans-cellular and forms a stable intercellular adhesion complex. ADGRL1 competes with neuroligin-1 for neurexin binding. Saturation binding assays, deletion mapping of extracellular domains, cell adhesion assays (co-culture of neurexin- and ADGRL1-expressing cells) The Journal of biological chemistry High 22262843
2010 ADGRL1/CIRL-1 undergoes constitutive autoproteolytic cleavage at its GPS domain in the endoplasmic reticulum, producing a heterodimeric two-subunit receptor complex (NTF + CTF). Protein kinase C activators (PMA and ionomycin) inhibit GPS cleavage and downregulate trafficking to the cell surface, causing accumulation of the uncleaved precursor intracellularly. A non-cleavable mutant showed that downregulation of trafficking is independent of cleavage, suggesting that GPS proteolysis is not purely autocatalytic and may require auxiliary factors. Transfection of wild-type and mutant CIRL-1 in cells, treatment with PKC activators PMA and ionomycin, trafficking/surface expression assays, non-cleavable soluble mutant analysis Biochimie Medium 20100540
2018 Comprehensive mutagenesis of the transmembrane domain (TMD) of ADGRL1/latrophilin-1 identified specific TMD residues essential for basal constitutive activity and for agonist peptide (endogenous tethered agonist peptide) response. A cancer-associated TMD mutation showed increased basal activity and failed to rescue embryonic developmental phenotype in transgenic C. elegans, linking TMD residues to receptor activation mechanism. Comprehensive mutagenesis screen of TMD residues, functional assays for basal activity and agonist peptide response, transgenic C. elegans rescue experiments iScience High 30428326
2019 Alternative splicing of ADGRL1/latrophilin-1 at the cytoplasmic SSB site confers dual cAMP signaling: SSB-containing variants show both constitutive Gαi/o coupling (constitutive cAMP production) and ligand-dependent Gαs activation (cAMP increase upon neurexin or FLRT binding), whereas SSB-deficient variants show only ligand-dependent cAMP decrease. Neither variant increased intracellular Ca2+ or activated MAP kinase upon ligand binding. cAMP competitive binding assays, pertussis toxin treatment (Gαi/o inhibition), expression of SSB-containing vs SSB-deficient LPHN1 variants, Ca2+ and MAPK assays Annals of the New York Academy of Sciences Medium 31339586
2019 The C-terminal fragment (CTF) of latrophilin-1/ADGRL1 in synapses is phosphorylated on multiple sites. Phosphorylated CTF has high affinity for the N-terminal fragment (NTF) and co-purifies with it. Dephosphorylated CTF has lower affinity for NTF and can behave as a separate protein. α-Latrotoxin binding to NTF brings it together with receptor-like protein tyrosine phosphatase σ (RPTPσ), leading to CTF dephosphorylation and CTF release from the NTF–CTF complex. Affinity column co-purification, sucrose density gradient fractionation, phosphorylation analysis of synaptic preparations, α-latrotoxin binding experiments Annals of the New York Academy of Sciences Medium 31553068
2022 ADGRL1 haploinsufficiency impairs ligand-induced regulation of intracellular Ca2+ influx (shown by in vitro expression of human variants in neuroblastoma cells). In Adgrl1 knockout mice, loss of ADGRL1 causes increased spontaneous exocytosis of dopamine, acetylcholine, and glutamate from synaptic preparations, and Adgrl1-null neurons form synapses poorly in vitro, demonstrating that ADGRL1 regulates neurotransmitter release and synapse formation. In vitro Ca2+ influx assays in neuroblastoma cells expressing human ADGRL1 variants; ex vivo synaptic preparations measuring spontaneous exocytosis; in vitro synapse formation assay in Adgrl1-/- neurons; mouse knockout on two genetic backgrounds American journal of human genetics High 35907405
2023 TAFA2 (a CNS-specific cytokine) directly binds to the lectin-like domain (Lec domain) of ADGRL1. This interaction activates the cAMP/PKA/CREB/BCL2 signaling pathway to suppress apoptosis. Overexpression of ADGRL1 lacking the Lec domain (ADGRL1ΔLec) failed to mediate TAFA2's anti-apoptotic effects, and ADGRL1-/- cells were unresponsive to recombinant TAFA2. Co-immunoprecipitation, quantitative mass spectrometry proteomics, pull-down assays, ADGRL1 knockout and Lec-deletion mutant overexpression, cAMP/p-PKA/p-CREB/BCL2 signaling measurements, apoptosis assays Life sciences High 37944639
2023 ADGRL1 binds glucose and functions as a glucose receptor in hypothalamic neurons. Validated by ligand-receptor binding assays in CHO cells stably expressing human ADGRL1. Adgrl1-deficient mice showed impaired glucose sensing by VMH neurons (electrophysiology), fasting hyperinsulinemia, enhanced glucose-stimulated insulin secretion, insulin resistance, and impaired feeding responses, demonstrating a role for ADGRL1 in energy and glucose homeostasis. Cell-based affinity chromatography to enrich glucose-bound neurons, proteomics identification, ligand-receptor binding assays in ADGRL1-expressing CHO cells, global and hypothalamus-specific Adgrl1 knockout mice, electrophysiology of VMH neurons, metabolic phenotyping Diabetologia High 37712955
2024 ADGRL1/LPHN1 deficiency in mice causes increased food consumption and severe obesity with dysregulated glucose homeostasis, and a partially inactivating human ADGRL1 mutation was identified in an obese patient, establishing ADGRL1 as a regulator of energy balance. Adgrl1-deficient mouse metabolic phenotyping (food intake, body weight, glucose homeostasis); human genetic variant functional characterization Signal transduction and targeted therapy Medium 38664368
2026 ADGRL1 ablation activates type I interferon signaling and promotes JAK/STAT1-dependent Decorin secretion by disrupting the GSK3β/β-catenin pathway, which facilitates cDC1–CD8+ T cell hub formation and anti-tumor immunity. An ADGRL1-targeting small molecule identified by virtual screening and DARTS showed antitumor efficacy in vivo. RNAi screening in Drosophila tumor model, single-cell transcriptomics, genetic KO in mice, pathway analysis (IFN/JAK/STAT1, GSK3β/β-catenin), Decorin secretion assays, PD-1 blockade combination, DARTS-based compound identification, in vivo tumor models Cell reports Medium 42172123
2026 ADGRL1/Latrophilin-1 recruits β-arrestins (βarr) constitutively at the plasma membrane and early endosomes. βarr recruitment is prerequisite for G-protein activation (all four G-protein families: Gs, Gi/o, Gq, G13); βarr or dynamin depletion suppressed G-protein biosensor activation, indicating endosomal priming of G-protein signaling. Splice-variant SSB determines differential trafficking kinetics and distinct βarr/G-protein complex assemblies (shared for Gs, divergent for Gq and G13) upon neurexin-1β stimulation. G-protein BRET biosensors, β-arrestin knockdown and knockout in HEK293 cells, dynamin inhibition, endosome-targeted biosensors, splice variant overexpression, receptor internalization imaging Biochimica et biophysica acta. Molecular cell research High 41819453
2024 ADGRL1 acts as a functional receptor for hevin/SPARCL1 in nucleus accumbens neurons. Hevin interacts with membrane-expressed ADGRL1, induces its internalization, stabilizes the uncleaved receptor fraction, and alters ADGRL1/Neurexin-1-mediated intercellular adhesion contacts. Hevin stimulation selectively modulates ADGRL1 G-protein coupling with bias toward Gi3, Gs, and G13. Pan-neuronal Adgrl1 deficiency in the nucleus accumbens impairs cocaine-induced reinforcement and reward. Co-IP, receptor internalization assays, cell adhesion assays, G-protein coupling BRET assays, mouse Adgrl1 knockdown in NAc, cocaine conditioned place preference and self-administration bioRxivpreprint Medium bio_10.1101_2024.07.03.601736
2025 Teneurin-4 (Ten4) switches between homophilic (Ten4–Ten4) and heterophilic (Ten4–ADGRL1/Latrophilin) interactions to direct cortical neuron migration along radial glial cells: in the intermediate zone, Ten4–Latrophilin/ADGRL1 interactions promote neuron–radial glial cell association, while in the cortical plate, Ten4–Ten4 dimerization reduces radial glial cell attachment. Cryo-EM of Ten2 showed that canonical Latrophilin binding is sterically incompatible with Teneurin dimerization, making the two interactions mutually exclusive. Single-particle cryo-EM (Ten2 structure), engineered surface mutations disrupting Ten-Ten or Ten-Latrophilin interactions, in vivo gene editing, super-resolution microscopy, proteomics bioRxivpreprint Medium bio_10.1101_2025.09.09.671438

Source papers

Stage 0 corpus · 26 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2017 The BABY BOOM Transcription Factor Activates the LEC1-ABI3-FUS3-LEC2 Network to Induce Somatic Embryogenesis. Plant physiology 209 28830937
2012 High affinity neurexin binding to cell adhesion G-protein-coupled receptor CIRL1/latrophilin-1 produces an intercellular adhesion complex. The Journal of biological chemistry 149 22262843
1998 Mutants of the CMP-sialic acid transporter causing the Lec2 phenotype. The Journal of biological chemistry 96 9685366
2017 Soybean LEC2 Regulates Subsets of Genes Involved in Controlling the Biosynthesis and Catabolism of Seed Storage Substances and Seed Development. Frontiers in plant science 88 28979275
2015 Senescence-inducible LEC2 enhances triacylglycerol accumulation in leaves without negatively affecting plant growth. Plant biotechnology journal 56 25790072
2018 A Comprehensive Mutagenesis Screen of the Adhesion GPCR Latrophilin-1/ADGRL1. iScience 52 30428326
2019 Variation in Expression of the HECT E3 Ligase UPL3 Modulates LEC2 Levels, Seed Size, and Crop Yields in Brassica napus. The Plant cell 49 31439805
2022 ADGRL1 haploinsufficiency causes a variable spectrum of neurodevelopmental disorders in humans and alters synaptic activity and behavior in a mouse model. American journal of human genetics 35 35907405
2019 Alternative splicing event modifying ADGRL1/latrophilin-1 cytoplasmic tail promotes both opposing and dual cAMP signaling pathways. Annals of the New York Academy of Sciences 18 31339586
2018 Expression and DNA methylation of SERK, BBM, LEC2 and WUS genes in in vitro cultures of Boesenbergia rotunda (L.) Mansf. Physiology and molecular biology of plants : an international journal of functional plant biology 18 30150851
2009 Efficient LEC2 activation of OLEOSIN expression requires two neighboring RY elements on its promoter. Science in China. Series C, Life sciences 18 19802745
2021 Development of Multidrug Resistance in Acute Myeloid Leukemia Is Associated with Alterations of the LPHN1/GAL-9/TIM-3 Signaling Pathway. Cancers 17 34298843
2023 ADGRL1 is a glucose receptor involved in mediating energy and glucose homeostasis. Diabetologia 15 37712955
2023 Neuronal survival factor TAFA2 suppresses apoptosis through binding to ADGRL1 and activating cAMP/PKA/CREB/BCL2 signaling pathway. Life sciences 15 37944639
2010 Regulation of CIRL-1 proteolysis and trafficking. Biochimie 15 20100540
2025 LEC2 induces somatic cell reprogramming through epigenetic activation of plant cell totipotency regulators. Nature communications 13 40328763
2024 Dysfunction of the adhesion G protein-coupled receptor latrophilin 1 (ADGRL1/LPHN1) increases the risk of obesity. Signal transduction and targeted therapy 13 38664368
2012 LEC-2, a highly variable lectin in the lichen Peltigera membranacea. Symbiosis (Philadelphia, Pa.) 11 23482294
2021 In silico characterization of putative gene homologues involved in somatic embryogenesis suggests that some conifer species may lack LEC2, one of the key regulators of initiation of the process. BMC genomics 9 34039265
2024 ADGRL1 variants: From developmental and epileptic encephalopathy to genetic epilepsy with febrile seizures plus. Developmental medicine and child neurology 5 38927006
2019 C-terminal phosphorylation of latrophilin-1/ADGRL1 affects the interaction between its fragments. Annals of the New York Academy of Sciences 5 31553068
2025 Bacteriophage cocktail LEC2-LEC10 for broad-spectrum control of pathogenic and uncharacterized Escherichia coli in fresh produce. Frontiers in microbiology 4 40458707
2025 B4GALT5-deficient CHO-Lec2 cells expressing human α1,4-galactosyltransferase: A glycoengineered cell model for studying Shiga toxin receptors. Biochemical and biophysical research communications 1 40036900
2025 Functional analysis of the woody oil crop Plukenetia volubilis L. LEC2 homolog PvoB3-69 in promoting regeneration. Plant cell reports 1 40319197
2026 Adhesion GPCR ADGRL1/Latrophilin-1 mobilizes β-arrestins as a prerequisite for endosomal restriction of G protein activation and splice-dependent scaffolds. Biochimica et biophysica acta. Molecular cell research 0 41819453
2026 Ablation of the adhesion G protein-coupled receptor ADGRL1 activates anti-tumor immune response via cDC1-T cell hub formation. Cell reports 0 42172123

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