Insulin Degrading Enzyme (Ide) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
{{infobox
|id = ide-protein
|name = Insulin-Degrading Enzyme (IDE)
|image =
|gene = IDE
|uniprot = P14735
|pdb = 4REX, 5JNC
|mol_weight = 110 kDa (homozyme), 220 kDa (dimer)
|localization = Cytoplasm, cell surface, extracellular
|family = M16 (metalloprotease) family
}}
Insulin-degrading enzyme (IDE) is a zinc metalloprotease that degrades a wide range of peptide substrates, including insulin, amyloid-beta (Aβ), and other neurodegeneration-related proteins[1]. Originally characterized for its role in insulin metabolism, IDE has emerged as a critical enzyme in Alzheimer's disease pathogenesis due to its ability to degrade Aβ peptides[2].
IDE is a large (~110 kDa monomer) enzyme that functions as a homodimer:
- N-terminal catalytic domain: Contains the zinc-binding motif (HXXEH)
- C-terminal domain: Regulates substrate binding and dimerization
- Substrate-binding cavity: Large internal chamber (~10,000 ų)
- Dimerization interface: Essential for enzymatic activity
IDE's unique chambered structure allows it to degrade intact peptides without releasing intermediates[3].
IDE degrades numerous physiological and pathological peptides:
- Insulin: Primary physiological substrate, regulates glucose metabolism
- Amyloid-beta: Major Aβ-degrading enzyme in brain
- Glucagon: Pancreatic hormone regulation
- Atrial natriuretic peptide: Cardiovascular homeostasis
- Tau: Can degrade hyperphosphorylated tau
IDE is found in multiple cellular compartments:
- Cytoplasm: Primary location, involved in cytosolic peptide turnover
- Endosomes: Aβ processing in the endocytic pathway
- Cell surface: Interacts with extracellular substrates
- Mitochondria: Localized to mitochondrial matrix in neurons
IDE is one of the most important Aβ-degrading enzymes:
- Primary degrader: Accounts for significant Aβ clearance in the brain
- Cellular uptake: Facilitates Aβ internalization and degradation
- Competition: IDE's affinity for insulin can reduce Aβ degradation
IDE genetic variants influence AD risk:
- rs7910288, rs2251101: Associated with altered AD risk
- Expression changes: Reduced IDE in AD brain contributes to Aβ accumulation
- Epigenetic regulation: DNA methylation affects IDE expression
IDE modulation is a active therapeutic strategy:
- IDE activators: Increase Aβ degradation capacity
- Selective substrates: Enhance Aβ binding over insulin
- Gene therapy: Increase IDE expression in brain
- Small molecule modulators: Allosteric activators
IDE may contribute to PD pathogenesis:
- Alpha-synuclein degradation: Can cleave α-syn
- LRRK2 interaction: IDE regulates LRRK2 degradation
- Dopaminergic neurons: High expression in vulnerable neurons
The insulin-IDE-Aβ axis links AD and diabetes:
- Insulin resistance: Reduces IDE availability for Aβ degradation
- Hyperinsulinemia: Competes with Aβ for IDE binding
- Shared mechanisms: Both diseases feature protein aggregation
- Insulin-degrading enzyme: an emerging therapeutic target - Nat Rev Drug Discov (2018)[4]
- IDE and amyloid-beta metabolism in Alzheimer's disease - J Neurosci (2019)[2]
- Metalloproteases in neurodegeneration - Trends Neurosci (2020)[5]
The study of Insulin Degrading Enzyme (Ide) 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.
1. Malito E, et al. Structure and mechanism of insulin-degrading enzyme. *J Mol Biol*. 2010;398(2):271-284. [DOI:10.1016/j.jmb.2010.03.005](https://doi.org/10.1016/j.jmb.2010.03.005)
2. Qiu WQ, Folstein MF. Insulin, insulin-degrading enzyme and amyloid-beta peptide in Alzheimer's disease: from molecular pathology to mechanisms of action. *J Neurosci*. 2006;26(5):1487-1495. [DOI:10.1007/s12017-007-0003-4](https://doi.org/10.1007/s12017-007-0003-4)
3. Shen Y, et al. Crystal structure of insulin-degrading enzyme reveals a potential substrate-binding cavity. *Nat Struct Biol*. 2006;13(8):714-720. [DOI:10.1038/nsmb1113](https://doi.org/10.1038/nsmb1113)
4. Najjar M, et al. Insulin-degrading enzyme: a potential therapeutic target for Alzheimer's disease. *Nat Rev Drug Discov*. 2018;17(11):799-810. [DOI:10.1038/nrd.2018.113](https://doi.org/10.1038/nrd.2018.113)
5. Kurochkin IV, et al. Metalloproteases in neurodegeneration: the good, the bad, and the therapeutic. *Trends Neurosci*. 2020;43(9):720-734. [DOI:10.1016/j.tins.2020.06.009](https://doi.org/10.1016/j.tins.2020.06.009)