title: β-Catenin regulates membrane potential in muscle cells by regulating the α2 subunit of Na,K-ATPase.
abstract: Muscle β-catenin has been shown to play a role in the formation of the neuromuscular junction (NMJ). Our previous studies showed that muscle-specific conditional knockout of β-catenin (HSA-β-cat(-/-) ) results in early postnatal death in mice. To understand the underlying mechanisms, we investigated the electrophysiological properties of muscle cells from HSA-β-cat(-/-) and control mice, and found that, in the absence of muscle β-catenin, the resting membrane potential (RMP) depolarised in muscle cells from the diaphragm, gastrocnemius and extensor digitorum longus muscles. Furthermore, in a primary line of mouse myoblasts (C2C12 cells) transfected with small-interfering RNAs targeting β-catenin, the RMP was depolarised as well. Finally, the expression levels of the α2 subunit of sodium/potassium adenosine triphosphatase were reduced by β-catenin knockdown in vitro or deletion in vivo. These results suggest a possible mechanism underlying the depolarised RMP in the absence of muscle β-catenin, and provide additional evidence supporting a role for β-catenin in the development of NMJs.
authors.affiliation: Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China.
authors.forename: Congying
authors.initials: C
authors.lastname: Zhao
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Kexin
authors.initials: K
authors.lastname: Li
authors.forename: Jianming
authors.initials: J
authors.lastname: Yang
authors.forename: Huimin
authors.initials: H
authors.lastname: Yu
authors.forename: Shumin
authors.initials: S
authors.lastname: Duan
authors.forename: Kewen
authors.initials: K
authors.lastname: Jiang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D003964:Diaphragm / Q000502:physiology*; D055785:Gene Knockdown Techniques; D015151:Immunoblotting; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000502:physiology*; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D046509:Tissue Culture Techniques; D014162:Transfection; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051176:beta Catenin; C401838:Atp1a2 protein, mouse; D000254:Sodium-Potassium-Exchanging ATPase
keywords: electrophysiology; ion channels; neuromuscular junction; skeletal muscle; transgenic mice