TY - JOUR
T1 - Muscle LIM protein plays both structural and functional roles in skeletal muscle
AU - Barash, Ilona A.
AU - Mathew, Liby
AU - Lahey, Michele
AU - Greaser, Marion L.
AU - Lieber, Richard L.
PY - 2005/11
Y1 - 2005/11
N2 - Muscle LIM protein (MLP) has been suggested to be an important mediator of mechanical stress in cardiac tissue, but the role that it plays in skeletal muscle remains unclear. Previous studies have shown that it is dramatically upregulated in fast-to-slow fiber-type transformation and also after eccentric contraction (EC)-induced muscle injury. The functional consequences of this upregulation, if any, are unclear. In the present study, we have examined the skeletal muscle phenotype of MLP-knockout (MLPKO) mice in terms of their response to EC-induced muscle injuries. The data suggest that while the MLPKO mice recover completely after EC-induced injury, their torque production lags behind that of heterozygous littermates in the early stages of the recovery process. This lag is accompanied by decreased expression of the muscle regulatory factor MyoD, suggesting that MLP may influence gene expression. In addition, there is evidence of type I fiber atrophy and a shorter resting sarcomere length in the MLPKO mice, but no significant differences in fiber type distribution. In summary, MLP appears to play a subtle role in the maintenance of normal muscle characteristics and in the early events of the recovery process of skeletal muscle to injury, serving both structural and gene-regulatory roles.
AB - Muscle LIM protein (MLP) has been suggested to be an important mediator of mechanical stress in cardiac tissue, but the role that it plays in skeletal muscle remains unclear. Previous studies have shown that it is dramatically upregulated in fast-to-slow fiber-type transformation and also after eccentric contraction (EC)-induced muscle injury. The functional consequences of this upregulation, if any, are unclear. In the present study, we have examined the skeletal muscle phenotype of MLP-knockout (MLPKO) mice in terms of their response to EC-induced muscle injuries. The data suggest that while the MLPKO mice recover completely after EC-induced injury, their torque production lags behind that of heterozygous littermates in the early stages of the recovery process. This lag is accompanied by decreased expression of the muscle regulatory factor MyoD, suggesting that MLP may influence gene expression. In addition, there is evidence of type I fiber atrophy and a shorter resting sarcomere length in the MLPKO mice, but no significant differences in fiber type distribution. In summary, MLP appears to play a subtle role in the maintenance of normal muscle characteristics and in the early events of the recovery process of skeletal muscle to injury, serving both structural and gene-regulatory roles.
KW - Eccentric contractions
KW - Passive tension
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U2 - 10.1152/ajpcell.00117.2005
DO - 10.1152/ajpcell.00117.2005
M3 - Article
C2 - 16093282
AN - SCOPUS:26844550733
SN - 0363-6143
VL - 289
SP - C1312-C1320
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 5 58-5
ER -