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Principal Investigator: Lalit Deshmukh
Organization: UNIVERSITY OF CALIFORNIA, SAN DIEGO
Fiscal Year: 2024
Award: $197,500
Funding agency: National Institute on Aging
Project Summary.
Human insulin-degrading enzyme (IDE) is a highly conserved dimeric zinc metalloprotease that hydrolyzes
various peptide substrates, such as insulin, amyloid-β (Aβ), glucagon, amylin, and HIV-1 p6. It is implicated in
several physiological and pathological processes, including insulin catabolism, amyloid-β (Aβ) clearance,
development of type II diabetes and Alzheimer’s disease (AD), as well as cognitive disorders and glucose
intolerance observed among people living with HIV. Surprisingly, in addition to hydrolyzing Aβ, IDE also acts as
a nonproteolytic chaperone against Aβ, resulting in its sequestration, followed by its controlled disposal. We
recently investigated the interactions of Aβ and HIV-1 p6 with catalytically inactive IDE using relaxation-based
solution NMR methods. We uncovered that modulation of intermolecular interactions allows IDE to differentiate
between non-amyloidogenic p6 and amyloidogenic Aβ. We also discovered that catalytically inactive IDE
prevented Aβ fibrillization at substoichiometric concentrations. The projects in this R21 proposal expand upon
these discoveries and will carry out innovative structure-function studies of IDE. Specifically, we will address two
outstanding questions in the field of IDE structural biology: the allosteric modulation of its catalytic activity (aim
1) and its remarkable nonproteolytic chaperone activity against Aβ (aim 2). Aim 1 is centered on our hypothesis
that substrate-induced closure of one IDE subunit will accelerate the opening of the other, allowing the products
to be released or substrate captured, and will provide key insights into how the substrate triggers these
conformational transitions as well as the complex network of intrasubunit and intersubunit interactions that
govern the catalytic activity of IDE. Under aim 2, we will generate a detailed quantitative picture of how inactive
IDE alters Aβ aggregation kinetics using a synergistic combination of fluorescence and NMR spectroscopy and
mathematical models based on the framework of microscopic rate laws and chemical kinetics. Extensive
preliminary results, including the production of milligram quantities of multiple catalytically active and inactive
IDE variants, and excellent NMR spectra of dimeric IDE acquired by introducing sparsely labelled methyl groups
in a perdeuterated environment, indicate the high feasibility of successfully completing the proposed studies.
Given the importance of IDE in the pathogenesis of AD, our research also has substantial medical relevance
and will lay the necessary foundation for an R01 proposal, geared toward bridging the gap between biophysical
and clinical studies and developing selective activators and variants of IDE for the treatment of AD.
Terms: <AD dementia><AD pathology><AIDS Virus><Abeta clearance><Abeta synthesis><Acceleration><Acquired Immune Deficiency Syndrome Virus><Acquired Immunodeficiency Syndrome Virus><Adult-Onset Diabetes Mellitus><Aging><Allosteric Regulation><Alzheimer Type Dementia><Alzheimer beta-Protein><Alzheimer disease dementia><Alzheimer sclerosis><Alzheimer syndrome><Alzheimer's><Alzheimer's Amyloid beta-Protein><Alzheimer's Disease><Alzheimer's amyloid><Alzheimer's disease pathology><Alzheimer's pathology><Alzheimers Dementia><Amyloid><Amyloid (Aβ) plaques><Amyloid Alzheimer's Dementia Amyloid Protein><Amyloid Beta-Peptide><Amyloid Plaques><Amyloid Protein A4><Amyloid Substance><Amyloid beta-Protein><Amyloid β><Amyloid β clearance><Amyloid β oligomer><Amyloid β production><Amyloid β synthesis><Amyloid β-Peptide><Amyloid β-Protein><Antibodies><Antidiabetic Hormone><Aβ><Aβ clearance><Aβ production><Aβ synthesis><AβO><Brain><Brain Nervous System><C-Fragment Endorphin><Catabolism><Cerebrum><Chaperone><Characteristics><Chemicals><Clinical Research><Clinical Study><Cognition Disorders><Complex><Cryo-electron Microscopy><Cryoelectron Microscopy><Degenerative Neurologic Disorders><Deterioration><Development><Dissection><Dysfunction><Electron Cryomicroscopy><Encephalon><Endopeptidases><Environment><Enzyme Gene><Enzyme Inhibition><Enzymes><Exhibits><Exocytosis><Fluorescence Spectroscopy><Foundations><Functional disorder><Genetic Polymorphism><Glucagon><Glucose Intolerance><Glukagon><HG-Factor><HIV><HIV-1><HIV-I><HIV1><Heat shock proteins><Human><Human Activities><Human Immunodeficiency Virus Type 1><Human Immunodeficiency Viruses><Human immunodeficiency virus 1><Humulin R><Hyperglycemic-Glycogenolytic Factor><In Vitro><Insulin><Insulin Protease><Insulin Proteinase><Insulin-Degrading Enzyme><Insulinase><Insulinoma amyloid peptide><Insulysin><KO mice><Ketosis-Resistant Diabetes Mellitus><Kinetics><Knock-out Mice><Knockout Mice><LAV-HTLV-III><Label><Late Onset Alzheimer Disease><Laws><Ligands><Lipotropin Fragment C><Lymphadenopathy-Associated Virus><Math Models><Maturity-Onset Diabetes Mellitus><Mediating><Medical><Metabolic Diseases><Metabolic Disorder><Metallopeptidases><Metalloproteases><Metalloproteinases><Methods><Microscopic><Modern Man><Molecular><Molecular Chaperones><Molecular Configuration><Molecular Conformation><Molecular Stereochemistry><NIDDM><NMR Spectrometer><NMR Spectroscopy><Nervous System Degenerative Diseases><Neural Degenerative Diseases><Neural degenerative Disorders><Neuritic Plaques><Neurodegenerative Diseases><Neurodegenerative Disorders><Neurologic Degenerative Conditions><Non-Insulin Dependent Diabetes><Non-Insulin-Dependent Diabetes Mellitus><Noninsulin Dependent Diabetes><Noninsulin Dependent Diabetes Mellitus><Novolin R><Nucleotides><Null Mouse><Organism-Level Process><Organismal Process><Pathogenesis><Pathologic Processes><Pathological Processes><Pathology><Pathway interactions><Peptide Peptidohydrolases><Peptides><Persons><Physiologic Processes><Physiological Processes><Physiopathology><Play><Polyphosphates><Prevention><Primary Senile Degenerative Dementia><Production><Property><Proteins><Proteome><Regular Insulin><Relaxation><Research><Risk><Roentgen Rays><Role><Senile Plaques><Site><Slow-Onset Diabetes Mellitus><Stable Diabetes Mellitus><Structure><System><T2 DM><T2D><T2DM><Therapeutic><Thesaurismosis><Type 2 Diabetes Mellitus><Type 2 diabetes><Type II Diabetes Mellitus><Type II diabetes><Variant><Variation><Virus-HIV><X-Radiation><X-Ray Radiation><X-ray><Xray><Zinc><Zn element><a beta peptide><a-beta peptide clearance><abeta><abeta accumulation><abeta aggregation><abeta deposition><abeta oligomer><abeta peptide clearance><abeta production><adult onset diabetes><age associated><age correlated><age dependent><age linked><age related><age specific><amlintide><amylin><amyloid beta><amyloid beta accumulation><amyloid beta aggregation><amyloid beta clearance><amyloid beta deposition><amyloid beta oligomer><amyloid beta peptide clearance><amyloid beta plaque><amyloid beta production><amyloid beta synthesis><amyloid β accumulation><amyloid β aggregation><amyloid β deposition><amyloid-b plaque><amyloid-b protein><aβ accumulation><aβ aggregation><aβ deposition><aβ oligomer><aβ plaques><beta amyloid fibril><beta-Endorphin><beta-Lipotropin C Fragment><biophysical analysis><biophysical approaches><biophysical methodology><biophysical methods><biophysical studies><biophysical techniques><cerebral><chemical kinetics><cognitive disease><cognitive disorder><cognitive syndrome><conformation><conformational><conformational conversion><conformational state><conformational transition><conformationally><conformations><cored plaque><cryo-EM><cryoEM><cryogenic electron microscopy><degenerative diseases of motor and sensory neurons><degenerative neurological diseases><design><designing><developmental><diabetes associated peptide><diffuse plaque><dimer><enzyme activity><enzyme structure><innovate><innovation><innovative><insight><insulin dimers><insulinoma amyloid polypeptide><intermolecular interaction><islet amyloid polypeptide><ketosis resistant diabetes><kinetics (chemistry)><late onset alzheimer><mathematic model><mathematical model><mathematical modeling><maturity onset diabetes><metabolism disorder><methyl group><milligram><monomer><neurodegenerative illness><new therapeutic approach><new therapeutic intervention><new therapeutic strategies><new therapy approaches><new treatment approach><new treatment strategy><novel therapeutic approach><novel therapeutic intervention><novel therapeutic strategies><novel therapy approach><nuclear magnetic resonance spectroscopy><oAβ><oligomeric amyloid beta><oligomeric amyloid-β><overexpress><overexpression><pancreatic amylin><pathophysiology><pathway><polymorphism><prevent><preventing><primary degenerative dementia><protein homeostasis><proteostasis><senile dementia of the Alzheimer type><social role><soluble amyloid precursor protein><stress protein><structural biology><type 2 DM><type II DM><type two diabetes><β-Endorphin>