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Structure, function, and disease biology of MICU1/MICU2

MICU1/MICU2的结构、功能和疾病生物学

基本信息

批准号：
9980297
负责人：
Zenon Grabarek
金额：
$ 46.43万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9980297
关键词：
Affinity Alleles Animals Binding Bioenergetics Biology Biophysics Calcium Calcium Binding Calcium Channel Calcium Signaling Calcium-Binding Proteins Cell Line Cells Clinical Communication Complex Cryoelectron Microscopy Data Defect Disease EF Hand Motifs Electrons Electrophysiology (science)Energy Metabolism Engineering Enzymes Escherichia coli Exercise Fatigue Fiber Genetic Genomics Goals Grant Histocytochemistry Histology Homeostasis Homologous Gene Human Human Genome Inherited Ion Channel Kinetics Knock-out Knockout Mice Lead Length Lesion Measures Membrane Potentials Metabolic Mitochondria Mitochondrial Myopathies Modeling Molecular Mus Muscle Muscle Contraction Muscle Fatigue Muscle Weakness Mutation Myopathy NADH Names Neurologic Organelles Oxygen Consumption Patients Performance Peripheral Physiology Plasma Positioning Attribute Process Production Property Proteins Regulation Reporting Resolution Rest Roentgen Rays Role Signal Transduction Skeletal Muscle Strenuous Exercise Structural Models Structure System Technology Testing Tissues Work X-Ray Crystallography common symptom design exercise intolerance genome editing in vivo loss of function mutation metabolic profile metabolomics mouse model mutant nervous system disorder neurotransmission response uptake

项目摘要

ABSTRACT Mitochondria uptake calcium via a calcium activated channel called the uniporter. Calcium uptake allows the organelle's metabolic state to be matched to rapidly changing energy requirements, and, in turn, tune key processes such as neurotransmission and muscle contraction. The uniporter is calcium-activated calcium channel regulated by the calcium binding heterodimer MICU1/MICU2. Mutations in MICU1 have recently been identified as a cause of a new form of a myopathy characterized by fatigue and exercise intolerance without the classical features of mitochondrial myopathy. The precise mechanisms by which MICU1 and MICU2 sense calcium to regulate the uniporter, and how lesions in this heterodimer lead to this highly unusual myopathy are not known. Through this dual PI grant we propose to: (1) Characterize the physicochemical properties of MICU1 and MICU2. The wild type proteins and mutants expressed in E. coli will be characterized with respect to the oligomeric state, structural stability, Ca2+ and Mg2+ binding affinities, and pH sensitivity. (2) Determine the structural basis for the regulation of the uniporter by MICU1 and MICU2. High resolution X-ray structures of MICU2 alone and of the MICU1/2 heterodimer in the apo and Ca2+-bound forms will be determined. Electron cryo-microscopy will be used to determine the structure of a native-like oligomer of MICU1/2 complex. (3) Investigate mitochondrial calcium dynamics in cellular systems. Using genome-editing technology we have engineered a powerful in vivo system of knockout cell lines for studying the effects of engineered and naturally occurring human mutations in MICU1 and MICU2 on the mitochondrial calcium transport kinetics and energetics, and (4) Understand the metabolic and bioenergetic basis of human MICU1 myopathy by investigating the Micu1-/- mouse as a model. We will characterize the muscle histology, mitochondrial bioenergetics, exercise performance and metabolomics, and single fiber contractility to test the hypothesis that loss of MICU1 leads to a myopathy by causing disturbances in energy metabolism. Our aims – spanning the molecular to animal physiology -- will yield a holistic and mechanistic understanding of the regulation of mitochondrial calcium uptake by MICU1 and MICU2 and its contribution to a newly described human myopathy.

摘要