Alpha B-crystallin in skeletal muscle: purification and localization.
Atrophy of rat soleus muscles by hindlimb suspension is characterized by an early dramatic decrease in a soluble 22-kDa protein. The 22-kDa protein was purified from rat red skeletal muscle and rat lens by three different methods of chromatography. The partial amino acid sequence (65% of total amino acids) determined for muscle 22-kDa protein was identical with that of rat lens crystallin. The HPLC elution patterns of lysylendopeptidase fragments of 22-kDa protein from the two sources were identical. Polyclonal antibodies to rat muscle and bovine lens alpha B-crystallin with the two proteins on immunoblotting. alpha B-Crystallin protein was expressed and synthesized efficiently in slow skeletal muscle and poorly in fast muscle. Thus, the decreased 22-kDa protein of slow muscle in the suspension treatment was confirmed to be alpha B-crystallin. Immunoblotting confirmed that most of the alpha B-crystallin was solubilized, though some was tightly bound to myofibrils. This bound portion was localized in Z-bands of isolated myofibrils by immunocytochemical light and electron microscopy. Muscle alpha B-crystallin is tentatively proposed to be a myofibril-stabilizing protein, based upon its extraction characteristics, localization, and amino acid sequence.
Atomi
Y
Y
Department of Sports Sciences, College of Arts & Sciences, University of Tokyo.
Yamada
S
S
Strohman
R
R
Nonomura
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000737:chemistry; D002417:Cattle; D002846:Chromatography, Affinity; D003459:Crystallins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification*; D015151:Immunoblotting; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009124:Muscle Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification*; D009132:Muscles / Q000737:chemistry* / Q000378:metabolism; D009133:Muscular Atrophy / Q000378:metabolism; D011487:Protein Conformation; D051381:Rats; D011919:Rats, Inbred Strains
D000906:Antibodies; D003459:Crystallins; D009124:Muscle Proteins