title: The Inhibitory Core of the Myostatin Prodomain: Its Interaction with Both Type I and II Membrane Receptors, and Potential to Treat Muscle Atrophy.
abstract: Myostatin, a muscle-specific transforming growth factor-β (TGF-β), negatively regulates skeletal muscle mass. The N-terminal prodomain of myostatin noncovalently binds to and suppresses the C-terminal mature domain (ligand) as an inactive circulating complex. However, which region of the myostatin prodomain is required to inhibit the biological activity of myostatin has remained unknown. We identified a 29-amino acid region that inhibited myostatin-induced transcriptional activity by 79% compared with the full-length prodomain. This inhibitory core resides near the N-terminus of the prodomain and includes an α-helix that is evolutionarily conserved among other TGF-β family members, but suppresses activation of myostatin and growth and differentiation factor 11 (GDF11) that share identical membrane receptors. Interestingly, the inhibitory core co-localized and co-immunoprecipitated with not only the ligand, but also its type I and type II membrane receptors. Deletion of the inhibitory core in the full-length prodomain removed all capacity for suppression of myostatin. A synthetic peptide corresponding to the inhibitory core (p29) ameliorates impaired myoblast differentiation induced by myostatin and GDF11, but not activin or TGF-β1. Moreover, intramuscular injection of p29 alleviated muscle atrophy and decreased the absolute force in caveolin 3-deficient limb-girdle muscular dystrophy 1C model mice. The injection suppressed activation of myostatin signaling and restored the decreased numbers of muscle precursor cells caused by caveolin 3 deficiency. Our findings indicate a novel concept for this newly identified inhibitory core of the prodomain of myostatin: that it not only suppresses the ligand, but also prevents two distinct membrane receptors from binding to the ligand. This study provides a strong rationale for the use of p29 in the amelioration of skeletal muscle atrophy in various clinical settings.
authors.affiliation: Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ohsawa
authors.affiliation: Department of Medicinal Chemistry, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Takayama
authors.affiliation: Department of Molecular and Developmental Biology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan.
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Nishimatsu
authors.affiliation: Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan; National Research Center for Protozoan Diseases (NRCPD), Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan; Department of Health and Sports Sciences, Faculty of Medical Professions, Kawasaki University of Medical Welfare, Kurashiki, Okayama, 701-0193, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujino
authors.affiliation: Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Fukai
authors.affiliation: Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan.
authors.forename: Tatsufumi
authors.initials: T
authors.lastname: Murakami
authors.affiliation: Department of Medical Science, Teikyo University of Science, Uenohara, Yamanashi, 409-0193, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hagiwara
authors.affiliation: Laboratory of Cardiovascular Medicine, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Itoh
authors.affiliation: Division for Therapies against Intractable Diseases, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Tsuchida
authors.affiliation: Department of Medicinal Chemistry, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan.
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Sunada
mesh_terms: D028341:Activins / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D051244:Caveolin 3 / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D021961:Cell Membrane Structures / Q000378:metabolism; D002522:Chlorocebus aethiops; D055412:Growth Differentiation Factors / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D008297:Male; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism; D009133:Muscular Atrophy / Q000378:metabolism*; D049288:Muscular Dystrophies, Limb-Girdle / Q000378:metabolism; D032446:Myoblasts / Q000378:metabolism; D055435:Myostatin / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D011956:Receptors, Cell Surface / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D051244:Caveolin 3; D055412:Growth Differentiation Factors; D008024:Ligands; D055435:Myostatin; D011956:Receptors, Cell Surface; D053773:Transforming Growth Factor beta1; D028341:Activins