GO:0004951 cholecystokinin receptor activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004951 cholecystokinin receptor activity describes the molecular function of binding cholecystokinin (CCK) and transmitting the signal across the membrane by activating an associated G-protein.
• The type 1 cholecystokinin receptor (CCK1R, also known as CCKAR) is the prototypical receptor for this activity and is a class A G-protein-coupled receptor.
• CCK1R activation triggers multiple intracellular signaling cascades, including protein kinase C (PKC)-dependent and independent pathways, tyrosine phosphorylation of focal adhesion kinase (p125FAK) and proline-rich kinase 2 (PYK2), and activation of protein kinase D1 (PKD1) [1,3,4].
• Cholecystokinin receptor activity is essential for physiological processes such as pancreatic enzyme secretion, gallbladder contraction, gastrointestinal motility, and satiation signaling via vagal afferents [6,8].
• Dysregulated CCK receptor signaling is implicated in acute pancreatitis, pancreatic cancer, and metabolic disorders such as obesity and type 2 diabetes [7,8].
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable precise dissection of CCK receptor signaling in pancreatic acinar cells and vagal afferent neurons [1,6].
Description
Cholecystokinin receptor activity (GO:0004951) is a molecular function that mediates the cellular response to cholecystokinin (CCK), a peptide hormone and neuropeptide that regulates digestion and satiety. This activity is defined by the binding of CCK to its receptor and the subsequent transmission of a signal across the membrane via activation of an associated G-protein, initiating changes in cell activity. The receptor responsible for this function, the type 1 cholecystokinin receptor (CCK1R), is a G-protein-coupled receptor (GPCR) that is widely expressed in the gastrointestinal tract, pancreas, and nervous system [2,8]. Researchers study cholecystokinin receptor activity to understand fundamental mechanisms of hormone and neurotransmitter signaling, as well as its roles in pancreatic physiology, gut-brain communication, and metabolic regulation [6,8]. Dysregulation of this activity has been linked to acute pancreatitis, pancreatic cancer, and obesity, making it a target for therapeutic intervention [7,8]. The molecular details of CCK1R signaling, including its activation of protein kinase C (PKC), protein kinase D1 (PKD1), and tyrosine phosphorylation events, have been elucidated through biochemical and genetic approaches [1,3,4]. This article provides a comprehensive overview of the ontology, mechanism, key genes, disease relevance, and research methods associated with GO:0004951, with a focus on CRISPR-based strategies for functional interrogation.
cholecystokinin receptor activity At A Glance
| GO ID | GO:0004951 |
|---|---|
| GO term | cholecystokinin receptor activity |
| Ontology | molecular_function |
| Synonym | CCK receptor activity |
| Major function | Binding cholecystokinin and activating G-protein-mediated signaling |
| Definition | Combining with cholecystokinin and transmitting the signal across the membrane by activating an associated G-protein to initiate a change in cell activity. |
| Related receptor | Type 1 cholecystokinin receptor (CCK1R/CCKAR), a class A GPCR |
| Tissue distribution | Pancreatic acinar cells, gallbladder, vagal afferent neurons, and central nervous system |
| Physiological roles | Pancreatic enzyme secretion, gallbladder contraction, satiation, gut motility |
What Is GO:0004951?
Cholecystokinin receptor activity (GO:0004951) is the molecular function of combining with cholecystokinin and transmitting the signal across the membrane by activating an associated G-protein to initiate a change in cell activity. Cholecystokinin can act as a neuropeptide or as a gastrointestinal hormone. This activity is synonymous with CCK receptor activity and is a type of G-protein-coupled receptor activity.
Why Is cholecystokinin receptor activity Important in Cell Biology?
Cholecystokinin receptor activity is central to the regulation of digestion and energy balance, and its dysfunction is implicated in several human diseases. The receptor mediates the effects of CCK on pancreatic acinar cells, including enzyme secretion and cellular growth, and on vagal afferent neurons to promote satiation [6,8]. Understanding this activity at the molecular level is essential for developing therapies for acute pancreatitis, pancreatic cancer, and metabolic disorders such as obesity and type 2 diabetes [7,8].
• Regulates pancreatic enzyme secretion and acinar cell function [1,3].
• Mediates gallbladder contraction and gastrointestinal motility.
• Plays a key role in satiation signaling via vagal afferent neurons.
• Implicated in the pathogenesis of acute pancreatitis.
• Associated with pancreatic cancer progression and metabolic disorders.
• Serves as a target for therapeutic interventions in obesity and diabetes.
• Provides a model for studying GPCR signaling and desensitization.
• Involved in neuropeptide signaling in the central nervous system.
Molecular Mechanism of cholecystokinin receptor activity
Ligand Binding and Receptor Activation
In simple terms: CCK binds to the receptor, which changes shape and activates a G-protein inside the cell.
Cholecystokinin receptor activity begins with the binding of CCK to the extracellular domain of the type 1 cholecystokinin receptor (CCK1R), a class A G-protein-coupled receptor. This binding induces a conformational change in the receptor that enables it to act as a guanine nucleotide exchange factor for an associated heterotrimeric G-protein, typically Gq/11, leading to the exchange of GDP for GTP on the G-alpha subunit and dissociation of the G-beta-gamma dimer. The activated G-protein subunits then modulate downstream effectors, such as phospholipase C-beta, to initiate signaling cascades.
Protein Kinase C Activation and Tyrosine Phosphorylation
In simple terms: The signal turns on enzymes that add phosphate groups to other proteins, changing their activity.
Activation of CCK1R leads to the stimulation of protein kinase C (PKC) isoforms, particularly PKC-delta, which is tyrosine phosphorylated in pancreatic acinar cells. This phosphorylation is regulated bidirectionally by PKC activation itself. Additionally, CCK1R activation induces tyrosine phosphorylation of p125FAK and proline-rich kinase 2 (PYK2), which are differentially regulated and contribute to cytoskeletal reorganization and cellular responses.
Activation of Protein Kinase D1 (PKD1)
In simple terms: Another kinase, PKD1, gets turned on and helps transmit the signal to the nucleus and other cell parts.
CCK causes activation of protein kinase D1 (PKD1) in pancreatic acini through signaling pathways that involve PKC-delta and PKC-independent mechanisms. PKD1 activation is a key event in CCK-stimulated pancreatic enzyme secretion and may regulate gene expression and cell proliferation.
G-Protein Coupling and Downstream Effectors
In simple terms: The activated G-protein turns on other proteins that carry the signal forward.
The G-protein coupled to CCK1R is primarily of the Gq/11 family, which activates phospholipase C-beta to produce inositol trisphosphate (IP3) and diacylglycerol (DAG), leading to calcium release and PKC activation. These second messengers propagate the signal to various downstream targets, including ion channels, kinases, and transcription factors, ultimately resulting in physiological responses such as enzyme secretion and changes in gene expression [1,3].
Receptor Desensitization and Internalization
In simple terms: After signaling, the receptor is turned off and brought inside the cell to stop the response.
Following prolonged stimulation, CCK1R undergoes desensitization and internalization, processes that are critical for terminating the signal and preventing cellular overstimulation. These events involve phosphorylation of the receptor by G-protein-coupled receptor kinases (GRKs) and binding of arrestins, which uncouple the receptor from G-proteins and target it for endocytosis. Dysregulation of these processes can contribute to pathological conditions such as pancreatitis.
Key Genes Involved in GO:0004951 cholecystokinin receptor activity
The following genes and proteins are key components of cholecystokinin receptor activity and its downstream signaling pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CCKAR (CCK1R) | Type 1 cholecystokinin receptor; binds CCK and activates G-proteins | Primary receptor for GO:0004951; target for knockout and point mutation studies [2,8] |
| CCK | Ligand for CCK1R; neuropeptide and gastrointestinal hormone | Essential for receptor activation; used in stimulation experiments |
| GNAQ | G-alpha q subunit; couples CCK1R to phospholipase C-beta | Mediates downstream signaling; knockout models alter CCK responses |
| GNA11 | G-alpha 11 subunit; alternative Gq/11 family member | Compensatory roles in CCK signaling; double knockout studies |
| PRKCD | Protein kinase C delta; tyrosine phosphorylated upon CCK stimulation | Key downstream effector; point mutations affect enzyme secretion |
| PKD1 (PRKD1) | Protein kinase D1; activated by CCK via PKC-dependent and independent pathways | Regulates secretion and gene expression; knockout impairs acinar function |
| PTK2 (FAK) | Focal adhesion kinase; tyrosine phosphorylated by CCK1R activation | Cytoskeletal remodeling; knockout affects cell motility |
| PYK2 (PTK2B) | Proline-rich kinase 2; tyrosine phosphorylated by CCK1R | Signaling scaffold; knockout alters CCK-induced responses |
| PLCB1 | Phospholipase C beta 1; produces IP3 and DAG | Downstream effector; knockout reduces calcium signaling |
| ARRB1 | Beta-arrestin 1; mediates receptor desensitization | Regulates CCK1R internalization; knockout prolongs signaling |
| ARRB2 | Beta-arrestin 2; mediates receptor desensitization | Regulates CCK1R internalization; knockout prolongs signaling |
| GRK2 | G-protein-coupled receptor kinase 2; phosphorylates CCK1R | Desensitization; overexpression enhances receptor phosphorylation |
| GRK3 | G-protein-coupled receptor kinase 3; phosphorylates CCK1R | Desensitization; overexpression enhances receptor phosphorylation |
| CCKBR (CCK2R) | Type 2 cholecystokinin receptor; binds CCK and gastrin | Related receptor with distinct functions; knockout models |
| SLC4A2 | Anion exchanger; regulated by CCK in pancreatic ducts | Indirect target; knockout affects bicarbonate secretion |
| MAPK1 (ERK2) | Mitogen-activated protein kinase 1; activated by CCK | Proliferation and gene expression; knockout affects growth |
| MAPK3 (ERK1) | Mitogen-activated protein kinase 3; activated by CCK | Proliferation and gene expression; knockout affects growth |
| JUN | Transcription factor; downstream of CCK signaling | Gene regulation; knockout alters CCK-induced transcription |
How Is cholecystokinin receptor activity Regulated?
Cholecystokinin receptor activity is regulated at multiple levels, including receptor desensitization, internalization, and feedback phosphorylation. Following CCK stimulation, CCK1R is phosphorylated by G-protein-coupled receptor kinases (GRKs) and binds beta-arrestins, leading to uncoupling from G-proteins and internalization. This process is critical for terminating the signal and preventing overstimulation. Additionally, PKC-mediated phosphorylation of downstream effectors such as PKC-delta and PKD1 provides feedback regulation of the signaling cascade [1,4]. Dysregulation of these regulatory mechanisms can contribute to pathological conditions such as acute pancreatitis.
cholecystokinin receptor activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CCKAR | Acute pancreatitis, pancreatic cancer, obesity | Knockout mouse, point mutation knock-in, overexpression in acinar cells [7,8] |
| CCK | Pancreatitis, satiation disorders | Knockout mouse, overexpression [5,6] |
| PRKCD | Pancreatitis, pancreatic cancer | Point mutation knock-in, knockout |
| PKD1 | Pancreatic cancer, secretion disorders | Knockout, overexpression |
| PTK2 | Pancreatic cancer, metastasis | Knockout, point mutation |
Acute Pancreatitis
Cholecystokinin receptor activity is a major factor in the development of acute pancreatitis. Studies in experimental models have shown that CCK receptor blockade and inhibition of proteolytic enzyme activity have beneficial effects in acute hemorrhagic pancreatitis, providing evidence for CCK as a key mediator of pancreatic injury. Hyperstimulation of CCK1R leads to premature activation of digestive enzymes within acinar cells, causing autodigestion and inflammation.
Pancreatic Cancer
Dysregulated CCK receptor signaling has been implicated in pancreatic cancer progression. The type 1 cholecystokinin receptor promotes cell proliferation and survival through activation of mitogenic pathways, including MAPK and PKD1 [1,8]. Targeting CCK1R signaling is considered a potential therapeutic strategy for pancreatic cancer.
Metabolic Disorders
Cholecystokinin receptor activity plays a role in satiation and energy balance. Vagal afferent CCK1R activation is required for glucagon-like peptide-1 (GLP-1)-induced satiation, linking CCK signaling to the control of food intake. Dysregulation of this pathway contributes to obesity and type 2 diabetes, making CCK1R a therapeutic target for metabolic disorders.
From cholecystokinin receptor activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of CCK1R in pancreatic enzyme secretion? | CCKAR knockout mouse or CRISPR knockout in acinar cell lines [1,3] |
| How does CCK1R point mutation affect ligand binding? | CRISPR point mutation knock-in of CCKAR in cell lines |
| What are the downstream effectors of CCK1R activation? | Knock-in of tagged CCK1R for proteomics [1,3] |
| Does overexpression of CCK1R promote pancreatic cancer? | Overexpression of CCKAR in pancreatic cancer cell lines or mouse models |
| How does CCK1R signaling regulate satiation? | Vagal afferent-specific knockout of CCKAR in mice |
| What is the effect of CCK1R desensitization on pancreatitis? | Knockout of GRK2/3 or beta-arrestins in acinar cells [2,7] |
How to Study the cholecystokinin receptor activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding | Receptor affinity and density | Characterization of CCK1R mutants |
| Calcium imaging | Intracellular calcium release | Real-time receptor activation in acinar cells |
| Immunoprecipitation and Western blot | Tyrosine phosphorylation of FAK, PYK2, PKC-delta | Analysis of downstream signaling [3,4] |
| Kinase activity assay | PKD1 activation | Measurement of CCK-induced kinase activity |
| CRISPR knockout screen | Identification of genes required for CCK signaling | Functional genomics in acinar cell lines [1,4] |
| RNA-seq | Transcriptional changes upon CCK stimulation | Gene expression profiling |
| Proteomics | Protein-protein interactions and post-translational modifications | Mapping CCK1R signaling complexes |
| In vivo satiation assay | Food intake reduction by CCK | Vagal afferent-specific knockout mice |
Biochemical Assays for Receptor Activity
Cholecystokinin receptor activity can be measured using radioligand binding assays with labeled CCK to determine receptor affinity and density. Downstream signaling events, such as IP3 production, calcium mobilization, and PKC activation, are assessed using standard biochemical techniques [1,4].
Phosphoproteomics and Kinase Activity
Phosphoproteomic approaches, including immunoprecipitation and mass spectrometry, are used to identify tyrosine phosphorylation events on p125FAK, PYK2, and PKC-delta following CCK1R activation [3,4]. Kinase activity assays specifically measure the activation of PKD1 and other downstream kinases.
Genetic and CRISPR Screens
CRISPR knockout screens can identify genes required for CCK1R signaling and function. For example, knocking out candidate genes such as PRKCD or PKD1 in pancreatic acinar cells followed by CCK stimulation reveals their roles in enzyme secretion and gene expression [1,4].
In Vivo Models and Imaging
Animal models, including CCKAR knockout mice, are used to study the physiological consequences of loss of cholecystokinin receptor activity, such as impaired satiation and altered pancreatic function [6,7]. Imaging techniques, such as calcium imaging in isolated acinar cells, provide real-time readouts of receptor activation.
How CRISPR Can Be Used to Study GO:0004951 cholecystokinin receptor activity
Knockout
CRISPR knockout of CCKAR or downstream signaling genes (e.g., PRKCD, PKD1) in pancreatic acinar cell lines or mice allows researchers to determine the requirement of these genes for cholecystokinin receptor activity and its physiological outputs, such as enzyme secretion and calcium signaling [1,4].
Point Mutation
CRISPR point mutation knock-in can be used to introduce specific amino acid substitutions in CCK1R to study ligand binding, G-protein coupling, or phosphorylation sites. For example, mutating tyrosine residues in the receptor or downstream kinases can reveal their roles in signaling [2,4].
Knock-in
Knock-in of tagged CCK1R (e.g., HA or GFP) enables visualization, immunoprecipitation, and proteomic analysis of the receptor and its interacting partners in native cells. This approach is valuable for studying receptor trafficking and desensitization.
Overexpression
Overexpression of CCKAR or its downstream effectors in cell lines or transgenic mice can model gain-of-function states associated with pancreatic cancer or metabolic disorders, and can be used to screen for therapeutic inhibitors.
How EDITGENE Supports cholecystokinin receptor activity Research
Researchers studying cholecystokinin receptor activity-related genes often need to determine whether a candidate gene is causally involved in receptor signaling, downstream responses, or disease pathogenesis. EDITGENE provides a comprehensive suite of CRISPR-based services to enable precise genetic manipulation and functional interrogation of these genes in relevant cell models.
Contact EDITGENE today to design your custom CRISPR model for cholecystokinin receptor activity research.
Frequently Asked Questions About cholecystokinin receptor activity
What is cholecystokinin receptor activity?
Cholecystokinin receptor activity (GO:0004951) is the molecular function of binding cholecystokinin and transmitting a signal across the membrane by activating an associated G-protein, initiating changes in cell activity.
What genes are involved in cholecystokinin receptor activity?
Key genes include CCKAR (encoding the type 1 cholecystokinin receptor), CCK (the ligand), and downstream effectors such as GNAQ, PRKCD, PKD1, PTK2, and PYK2 [1,2,3,4,5].
What is the role of CCK1R in pancreatic acinar cells?
CCK1R mediates CCK-stimulated enzyme secretion, calcium signaling, and activation of kinases such as PKC-delta and PKD1 in pancreatic acinar cells [1,3,4].
How is cholecystokinin receptor activity regulated?
It is regulated by receptor desensitization and internalization, involving GRK-mediated phosphorylation and beta-arrestin binding, as well as feedback phosphorylation of downstream effectors.
What diseases are associated with cholecystokinin receptor activity?
Dysregulated CCK receptor signaling is implicated in acute pancreatitis, pancreatic cancer, and metabolic disorders such as obesity and type 2 diabetes [6,7,8].
How can CRISPR be used to study cholecystokinin receptor activity?
CRISPR knockout, point mutation, knock-in, and overexpression models allow precise manipulation of CCKAR and downstream genes to dissect their roles in receptor signaling and disease [1,2,4].
What are the downstream signaling pathways of CCK1R?
CCK1R activates Gq/11, phospholipase C-beta, PKC, PKD1, and tyrosine phosphorylation of FAK and PYK2, leading to calcium release and enzyme secretion [1,3,4,5].
Is CCK1R a therapeutic target?
Yes, CCK1R is considered a therapeutic target for obesity, type 2 diabetes, and pancreatic cancer due to its roles in satiation and cell proliferation [6,8].
What model systems are used to study cholecystokinin receptor activity?
Common models include pancreatic acinar cell lines, CCKAR knockout mice, and vagal afferent-specific knockout mice, as well as CRISPR-engineered cell lines [1,6,7].
What is the difference between CCK1R and CCK2R?
CCK1R (CCKAR) primarily binds CCK and mediates digestive and satiety effects, while CCK2R (CCKBR) binds both CCK and gastrin and is involved in gastric acid secretion and central nervous system functions.
Conclusion
Cholecystokinin receptor activity (GO:0004951) is a fundamental molecular function that mediates the diverse physiological effects of CCK, from pancreatic enzyme secretion to satiation. Its dysregulation contributes to acute pancreatitis, pancreatic cancer, and metabolic disorders, making it a critical area of biomedical research. Advances in CRISPR-based gene editing now enable precise interrogation of CCK1R and its downstream signaling network, offering new opportunities for therapeutic discovery.
References
- 1. Berna MJ et al.. 2007. CCK causes PKD1 activation in pancreatic acini by signaling through PKC-delta and PKC-independent pathways.. Biochim Biophys Acta 1773(4):483-501 PMID: 17306383
- 2. Dawson ES et al.. 2002. Moleular models for cholecystokinin-A receptor.. Pharmacol Toxicol 91(6):290-6 PMID: 12688371
- 3. Pace A et al.. 2003. Phosphospecific site tyrosine phosphorylation of p125FAK and proline-rich kinase 2 is differentially regulated by cholecystokinin receptor type A activation in pancreatic acini.. J Biol Chem 278(21):19008-16 PMID: 12651850
- 4. Tapia JA et al.. 2002. Cholecystokinin-stimulated tyrosine phosphorylation of PKC-delta in pancreatic acinar cells is regulated bidirectionally by PKC activation.. Biochim Biophys Acta 1593(1):99-113 PMID: 12431789
- 5. Gardner JD et al.. 1984. Cholecystokinin receptor antagonists.. Am J Physiol 246(5 Pt 1):G471-6 PMID: 6202155
- 6. Vana V et al.. 2022. Vagal afferent cholecystokinin receptor activation is required for glucagon-like peptide-1-induced satiation.. Diabetes Obes Metab 24(2):268-280 PMID: 34658116
- 7. Niederau C et al.. 1986. Beneficial effects of cholecystokinin-receptor blockade and inhibition of proteolytic enzyme activity in experimental acute hemorrhagic pancreatitis in mice. Evidence for cholecystokinin as a major factor in the development of acute pancreatitis.. J Clin Invest 78(4):1056-63 PMID: 2428840
- 8. Miller LJ et al.. 2016. Metabolic Actions of the Type 1 Cholecystokinin Receptor: Its Potential as a Therapeutic Target.. Trends Endocrinol Metab 27(9):609-619 PMID: 27156041
