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Regulation of MyBP-C slow via phosphorylation in skeletal muscles

通过骨骼肌磷酸化缓慢调节 MyBP-C

基本信息

批准号：
9769620
负责人：
Aikaterini Kontrogianni-Konstantopoulos
金额：
$ 17万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
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 2020-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9769620
关键词：
ATP phosphohydrolase Actins Actomyosin Adult Affect Aging Alanine Alternative Splicing Animal Model Arthrogryposis Atomic Force Microscopy Benchmarking Binding Biochemical Biological Biological Assay Biology Biomedical Research C10 Cardiac Cardiac Myosins Complex Cyclic AMP-Dependent Protein Kinases Development Distal Embryo Event Exons Exploratory/Developmental Grant Family Fatigue Fibronectins Filament Functional disorder Generations Genes Goals Growth Head Heart Immunoglobulin Domain In Vitro Individual Kinetics Knock-in Maintenance Mechanics Mediating Microfilaments Modeling Molecular Morphology Mus Muscle Muscle function Mutate Myocardium Myopathy Myosin ATPase Nature Phenotype Phosphorylation Phosphorylation Site Process Property Protein Isoforms Proteins Proteomics Protocols documentation RNA Splicing Regulation Role Sarcomeres Sedimentation process Side Site Skeletal Muscle Slide Striated Muscles Structure Testing Text Thick Thick Filament Thinness Variant biophysical properties blastocyst cell motility citrate carrier combinatorial embryonic stem cell exercise capacity high reward high risk homologous recombination in vivo mechanical properties mimetics mouse model muscle strength mutant myosin-binding protein C novel organizational structure response skeletal stem stressor tool

项目摘要

ABSTRACT Myosin Binding Protein-C (MyBP-C) comprises a family of thick filament associated proteins that contributes to their assembly and maintenance, and regulates the formation of actomyosin cross-bridges during contraction. Three distinct isoforms have been characterized, including the cardiac (c), slow (s) skeletal and fast (f) skeletal. The expression of the cardiac isoform is confined in the developing and mature heart, whereas the skeletal isoforms can co-exist in the same muscle. The core structure of MyBP-C consists of seven immunoglobulin (Ig) domains and three fibronectin-III (Fn-III) domains, numbered from the NH2-terminus as C1-C10. During the last forty years, numerous studies have focused on elucidating the mechanisms that modulate the activities of cMyBP-C in the formation of actomyosin cross-bridges. On the contrary, the regulation and roles of the skeletal isoforms have remained obscure, and mainly inferred due to the structural similarity they share with cMyBP-C. Our group has been studying the slow skeletal form of MyBP-C aiming to understand its regulation and activities. Using molecular tools, we have shown that the MYBPC1 gene, encoding sMyBP-C, is heavily spliced giving rise to multiple variants that can be co-expressed in the same muscle and myofiber. These share common domains, but also differ by the inclusion or skipping of novel insertions located in the NH2-terminus, the FN-III C7 domain and the COOH-terminus. Both the NH2 and COOH termini can retain native myosin and actin and modulate the sliding velocity of actin filaments past myosin heads, though to different extents and in a variant-specific manner. Moreover, using proteomic tools, we have demonstrated that sMyBP-C undergoes phosphorylation mediated by PKA and PKC. In particular, we have identified four phosphorylation sites in the NH2-terminus of the protein, with one of them located within a unique insertion present only in select variants. We therefore hypothesize that sMyBP-C comprises a multi- faceted family of thick filament accessory proteins whose functions are regulated via complex phosphorylation of its NH2-terminus. Our goals in the current proposal are to examine how phosphorylation affects the biochemical and biophysical properties of the different sMyBP-C variants (Aim 1), and to generate the first phospho-mutant sMyBP-C animal model to assess the role of phosphorylation in vivo (Aim 2). The proposed studies will greatly advance our understanding on the regulation of the multifaceted sMyBP-C subfamily via phosphorylation, which is an outstanding biological question with important and broad implications in muscle pathophysiology.

摘要