Molecular properties and gene expression of albumin in the skeletal muscle following hindlimb immobilization in a shortened position.
We investigated the effect of immobilization of hindlimb in a shortened position on proteins in the mouse soleus muscle and determined the molecular properties of a protein that had changed specifically in the atrophied muscle. A protein of 67.5 kDa was increased significantly (P<0.001) by 1.9-fold in the atrophied muscle compared to the control muscle as shown by sodium dodecyl sulfate-polyacrylamide (SDS-PAGE). The isoelectric point of the protein was pH 6.3 in two-dimensional PAGE. We carried out N-terminal and peptide mapping analyses to identify the primary structure of the protein. A 17-amino acid sequence showed 100% homology with the mouse serum albumin precursor. A peptide map of the 67.5-kDa protein was similar to that of mouse serum albumin. Mass spectrometry also showed the protein to be most similar to mouse serum albumin. Thus, based on these criteria, the 67.5-kDa protein was indistinguishable from mouse serum albumin. An immunohistochemical study showed that the 67.5-kDa protein was located mainly in the endomysium of the control muscle and had accumulated in the widened interstitial spaces of the atrophied muscle. A reverse transcription-PCR assay revealed that the albumin gene was expressed in skeletal muscle tissue, but that its expression was significantly lower in the atrophied muscle than in the control muscle (P<0.001). We conclude that albumin is increased in atrophied muscle and suggest that this may be of clinical importance for analyzing the process of muscular atrophy.
Wagatsuma
A
A
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan.
Yamazaki
Y
Y
Mizuno
K
K
Yamada
S
S
D000418:Albumins / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D001284:Atrophy / Q000378:metabolism / Q000473:pathology; D001835:Body Weight; D004591:Electrophoresis, Polyacrylamide Gel; D019417:Hindlimb Suspension / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D009124:Muscle Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D009929:Organ Size; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D021241:Spectrometry, Mass, Electrospray Ionization
D000418:Albumins; D009124:Muscle Proteins; D012333:RNA, Messenger