title: Alpha-actinin-3 levels increase concomitantly with fast fibers in rat soleus muscle.
abstract: Alpha (alpha)-actinin-3 is located in the skeletal muscle Z-line and forms actin-actin crosslinks. An interesting property of alpha-actinin-3 is its expression pattern, which is restricted to fast type II skeletal muscle fibers. However, little is known about the response of alpha-actinin-3 levels to changes in skeletal muscle such as fiber type transformation. This study examined alpha-actinin-3 levels in the soleus muscles of rats subjected to hindlimb unloading, which causes a slow-to-fast fiber transformation in the soleus muscle. After unloading, type II myosin heavy chain (MyHC) and fast myosin levels increased significantly (P<0.0001 for type II MyHC, P<0.005 for fast myosin). Along with these increases in fast fibers, alpha-actinin-3 expression levels increased significantly (P<0.0007) and dramatically. These results indicate that alpha-actinin-3 levels increase concomitantly with increases in skeletal muscle fast fibers.
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki, Kanagawa 216-8511, Japan. yuji_ogura@marianna-u.ac.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ogura
authors.forename: Hisashi
authors.initials: H
authors.lastname: Naito
authors.forename: Ryo
authors.initials: R
authors.lastname: Kakigi
authors.forename: Noriko
authors.initials: N
authors.lastname: Ichinoseki-Sekine
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Kurosaka
authors.forename: Shizuo
authors.initials: S
authors.lastname: Katamoto
mesh_terms: D000185:Actinin / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D005260:Female; D019417:Hindlimb Suspension; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism; D024462:Myosin Type II / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C530217:Actn3 protein, rat; D000185:Actinin; D024462:Myosin Type II; D018995:Myosin Heavy Chains