title: N-myristoylated ubiquitin ligase Cbl-b inhibitor prevents on glucocorticoid-induced atrophy in mouse skeletal muscle.
abstract: A DGpYMP peptide mimetic of tyrosine(608)-phosphorylated insulin receptor substrate-1 (IRS-1), named Cblin, was previously shown to significantly inhibit Cbl-b-mediated IRS-1 ubiquitination. In the present study, we developed N-myristoylated Cblin and investigated whether it was effective in preventing glucocorticoid-induced muscle atrophy. Using HEK293 cells overexpressing Cbl-b, IRS-1 and ubiquitin, we showed that the 50% inhibitory concentrations of Cbl-b-mediated IRS-1 ubiquitination by N-myristoylated Cblin and Cblin were 30 and 120 μM, respectively. Regarding the DEX-induced atrophy of C2C12 myotubes, N-myristoylated Cblin was more effective than Cblin for inhibiting the DEX-induced decreases in C2C12 myotube diameter and IRS-1 degradation. The inhibitory efficacy of N-myristoylated Cblin on IRS-1 ubiquitination in C2C12 myotubes was approximately fourfold larger than that of Cblin. Furthermore, N-myristoylation increased the incorporation of Cblin into HEK293 cells approximately 10-folds. Finally, we demonstrated that N-myristoylated Cblin prevented the wet weight loss, IRS-1 degradation, and MAFbx/atrogin-1 and MuRF-1 expression in gastrocnemius muscle of DEX-treated mice approximately fourfold more effectively than Cblin. Taken together, these results suggest that N-myristoylated Cblin prevents DEX-induced skeletal muscle atrophy in vitro and in vivo, and that N-myristoylated Cblin more effectively prevents muscle atrophy than unmodified Cblin.
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Ochi
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Abe
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan; National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8566, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Nakao
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Kitahata
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Marina
authors.initials: M
authors.lastname: Takagi
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Hirasaka
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ohno
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Shigetada
authors.initials: S
authors.lastname: Teshima-Kondo
authors.affiliation: Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Yonsei, Republic of Korea.
authors.forename: Gwag
authors.initials: G
authors.lastname: Taesik
authors.affiliation: Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Yonsei, Republic of Korea.
authors.forename: Inho
authors.initials: I
authors.lastname: Choi
authors.affiliation: Department of Pharmaceutical Chemistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kawamura
authors.affiliation: Department of Pharmaceutical Chemistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Nemoto
authors.affiliation: Department of Food Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Mukai
authors.affiliation: Department of Food Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Terao
authors.affiliation: Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan. Electronic address: nikawa@tokushima-u.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nikawa
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D002474:Cell-Free System; D005260:Female; D005938:Glucocorticoids / Q000009:adverse effects*; D057809:HEK293 Cells; D006801:Humans; D055504:Insulin Receptor Substrate Proteins / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D009133:Muscular Atrophy / Q000139:chemically induced; D019814:Myristic Acid / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D050721:Proto-Oncogene Proteins c-cbl / Q000037:antagonists & inhibitors / Q000378:metabolism*; D025801:Ubiquitin / Q000737:chemistry
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C118387:Cblb protein, mouse; D005938:Glucocorticoids; C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010455:Peptides; D025801:Ubiquitin; D019814:Myristic Acid; C492211:CBLB protein, human; D050721:Proto-Oncogene Proteins c-cbl
keywords: Cbl-b; IRS-1; Mice; Skeletal muscle atrophy; Ubiquitin ligase inhibitor