Loss of skeletal muscle strength by ablation of the sarcoplasmic reticulum protein JP45.
Skeletal muscle constitutes approximately 40% of the human body mass, and alterations in muscle mass and strength may result in physical disability. Therefore, the elucidation of the factors responsible for muscle force development is of paramount importance. Excitation-contraction coupling (ECC) is a process during which the skeletal muscle surface membrane is depolarized, causing a transient release of calcium from the sarcoplasmic reticulum that activates the contractile proteins. The ECC machinery is complex, and the functional role of many of its protein components remains elusive. This study demonstrates that deletion of the gene encoding the sarcoplasmic reticulum protein JP45 results in decreased muscle strength in young mice. Specifically, this loss of muscle strength in JP45 knockout mice is caused by decreased functional expression of the voltage-dependent Ca(2+) channel Ca(v)1.1, which is the molecule that couples membrane depolarization and calcium release from the sarcoplasmic reticulum. These results point to JP45 as one of the molecules involved in the development or maintenance of skeletal muscle strength.
Delbono
Osvaldo
O
Departments of Anaesthesia and Research, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland.
Xia
Jinyu
J
Treves
Susan
S
Wang
Zhong-Min
ZM
Jimenez-Moreno
Ramon
R
Payne
Anthony M
AM
Messi
María Laura
ML
Briguet
Alexandre
A
Schaerer
Florian
F
Nishi
Miyuki
M
Takeshima
Hiroshi
H
Zorzato
Francesco
F
D000818:Animals; D002118:Calcium / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053580:Muscle Strength / Q000235:genetics / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012519:Sarcoplasmic Reticulum / Q000235:genetics / Q000502:physiology*
C485996:JP-45 protein, mouse; D008565:Membrane Proteins; D002118:Calcium