Expression of endoplasmic reticulum stress proteins during skeletal muscle disuse atrophy

• Published in: American Journal of Physiology: Cell Physiology Vol. 281; no. 4; p. C1285
• Main Authors: Hunter, R B, Mitchell-Felton, H, Essig, D A, Kandarian, S C
• Format: Journal Article
• Language: English
• Published: United States 01-10-2001
• Subjects: Animals; Antioxidants - metabolism; Atrophy; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Calreticulin; Calsequestrin - genetics; Calsequestrin - metabolism; Carrier Proteins - genetics; Carrier Proteins - metabolism; CCAAT-Enhancer-Binding Proteins - genetics; CCAAT-Enhancer-Binding Proteins - metabolism; eIF-2 Kinase - genetics; eIF-2 Kinase - metabolism; Endoplasmic Reticulum - metabolism; Female; Gene Expression Regulation, Enzymologic; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; Heme Oxygenase (Decyclizing) - genetics; Heme Oxygenase (Decyclizing) - metabolism; Heme Oxygenase-1; Immobilization; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Muscle, Skeletal - enzymology; Muscle, Skeletal - pathology; Rats; Rats, Wistar; Ribonucleoproteins - genetics; Ribonucleoproteins - metabolism; RNA, Messenger - analysis; Sarcoplasmic Reticulum - metabolism; Transcription Factor CHOP; Transcription Factors - genetics; Transcription Factors - metabolism; Vinculin - genetics; Vinculin - metabolism
• ISSN: 0363-6143
• DOI: 10.1152/ajpcell.2001.281.4.c1285

Disuse atrophy of skeletal muscle leads to an upregulation of genes encoding sarcoplasmic reticulum (SR) calcium-handling proteins. Because many of the proteins that are induced with endoplasmic reticulum (ER) stress are ER calcium-handling proteins, we sought to determine whether soleus muscle atrophy was associated with a prototypical ER stress response. Seven days of rat hindlimb unloading did not alter expression of ubiquitous ER stress proteins such as Grp78, calreticulin, and CHOP/GADD-153, nor other proteins that have been shown to be activated by ER stressors such as vinculin, the type I D-myo-inositol 1,4,5-trisphosphate receptor, or protein kinase R, a eukaryotic initiation factor 2 alpha kinase. On the other hand, expression of heme oxygenase-1 (HO-1), an antioxidant ER stress protein, was significantly increased 2.2-fold. In addition, unloading led to an increase in calsequestrin, the muscle-specific SR calcium-binding protein, at both the mRNA (68%) and protein (24%) levels. Although disuse atrophy is associated with a significant remodeling of muscle-specific proteins controlling SR calcium flux, it is not characterized by a prototypical ER stress response. However, the upregulation of HO-1 may indicate ER adaptation to oxidative stress during muscle unloading.