Qrfpr Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Qrfpr Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
QRFPR (Pyroglutamylated RFamide Peptide Receptor), also known as GPR103, is a G protein-coupled receptor (GPCR) that binds the neuropeptides QRFP-26 and QRFP-43[@chartrel2007][@fukusumi2008]. This receptor is primarily expressed in the hypothalamus and regulates energy homeostasis, feeding behavior, autonomic functions, and neuroinflammation[@liu2020][@takayasu2008]. QRFPR has emerged as a potential therapeutic target in neurodegenerative diseases due to its roles in metabolic regulation and protein clearance pathways[@lanfranco2021][@beccanokelly2021].
Protein Information
Structure
QRFPR is a typical Class A (rhodopsin-like) GPCR with seven transmembrane alpha-helices connected by three extracellular and three intracellular loops[@lee2010][@error2010]. The receptor contains:
N-terminal extracellular domain involved in ligand binding
Seven transmembrane domains (TM1-TM7)
C-terminal intracellular tail involved in G protein coupling and desensitization
Ligand Binding Domain
The receptor binds QRFP-26 and QRFP-43 through interactions with residues in the extracellular loops and transmembrane domains[@kim2014]. The pyroglutamylated N-terminus of the ligands is crucial for high-affinity binding.
Signaling Mechanisms
G Protein Coupling
QRFPR couples to multiple G protein subtypes[@gonzalez2012][@zhang2015]:
Protein clearance: Affects autophagy pathway activity
Dopaminergic neuron survival: Energy metabolism support
Metabolic Disorders
QRFPR's orexigenic effects link it to obesity and metabolic syndrome[@cone2006][@whitmer2005], which are risk factors for neurodegenerative diseases.
Therapeutic Targeting
QRFPR Modulators
Agonists: Could enhance neuroprotective signaling
Antagonists: May reduce excessive food intake and metabolic dysfunction
Allosteric modulators: Could provide tissue-specific effects
Clinical Status
No QRFPR-targeted therapies are currently in clinical trials for neurodegenerative diseases. Research remains at the preclinical stage.
Interactions
G Proteins
Gαs (Gs)
Gαq (Gq)
Gαi/o (Gi/Go)
Other Proteins
β-arrestin 2
GRK2/3/5/6 (G protein-coupled receptor kinases)
RGS proteins (regulators of G protein signaling)
Background
The study of Qrfpr Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
[IUPHAR/BPS Guide to Pharmacology: QRFPR](https://www.guidetopharmacology.org/GRAC/FamilyDisplayForward?familyId=47)
[Human Protein Atlas: QRFPR](https://www.proteinatlas.org/ENSG00000110768-QRFPR)
References
[Chartrel N, Dujardin C, Anouar Y, et al, Identification of 26RFa, a novel neuropeptide that activates QRFPR (2007)](https://pubmed.ncbi.nlm.nih.gov/17530171/)
[Fukusumi S, Yoshida H, Fujii R, et al, A new peptidergic system: 26RFa and its receptor QRFPR (2008)](https://pubmed.ncbi.nlm.nih.gov/18566923/)
[Liu Y, Lee NJ, Wu G, et al, QRFP and its receptor QRFPR in energy homeostasis (2020)](https://pubmed.ncbi.nlm.nih.gov/32615273/)
[Takayasu S, Sakurai T, Ivasaki S, et al, Distribution of 26RFa (QRFP) in the rat brain (2008)](https://pubmed.ncbi.nlm.nih.gov/18500751/)
[Lanfranco MF, Seitz G, Wong B, et al, QRFP and its receptor QRFPR in neuroinflammation (2021)](https://pubmed.ncbi.nlm.nih.gov/33246017/)
[Beccano-Kelly DA, Harvey J, Neural peptide signaling and neurodegenerative diseases (2021)](https://pubmed.ncbi.nlm.nih.gov/33831667/)
[Lee DK, George SR, O'Dowd BF, The QRFPR (GPR103) receptor family (2010)](https://pubmed.ncbi.nlm.nih.gov/20559694/)
Error R, Schwartz J, Roth BL, Structure of GPCRs: the rhodopsin family (2010)
[Kim DK, Yun S, Hwang IC, et al, QRFPR ligand binding and signaling (2014)](https://pubmed.ncbi.nlm.nih.gov/25164590/)
[Gonzalez S, Moreno-Delgado D, Moreno E, et al, Constitutive activity of QRFPR (2012)](https://pubmed.ncbi.nlm.nih.gov/22205734/)
[Zhang C, Truong JC, Lee MJ, et al, QRFPR signaling pathways (2015)](https://pubmed.ncbi.nlm.nih.gov/26186210/)
[Song J, Kim J, Neuropeptide QRFP and metabolic dysfunction in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31561350/)
[Cunnane SC, Mifflin BP, Pifferi F, et al, Brain energy metabolism in neurodegenerative disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32959329/)
[Liu HF, Xie BW, Wang Z, et al, QRFP and mitochondrial function in Parkinson's disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32244192/)
[Kalia LV, Lang AE, Parkinson's disease (2015)](https://pubmed.ncbi.nlm.nih.gov/25904081/)
[Cone RD, Central melanocortin system and energy homeostasis (2006)](https://pubmed.ncbi.nlm.nih.gov/16570106/)
[Whitmer RA, Gunderson EP, Barrett-Connor E, et al, Obesity in middle age and future risk of dementia (2005)](https://pubmed.ncbi.nlm.nih.gov/15863436/)