DYNAMIC EXPRESSION OF ALPHA-B-CRYSTALLIN IN SKELETAL-MUSCLE - EFFECTS OF UNWEIGHTING, PASSIVE STRETCH AND DENERVATION

Twenty-two kDa protein specifically decreased in slow soleus muscle atrophy after 2-week hindlimb suspension (HS) of rats. This protein is abundant in soleus muscle but less in fast plantaris muscle. We purified this protein, determined the partial amino acid sequence using its proteolytic fragment, and found that the 22-kDa protein was a alpha-crystallin B chain with a 95% homology to bovine alpha-B-crystallin. Further we demonstrated that alpha-B-crystallin did not decrease in passively stretched slow muscle even under HS, and did markedly increase in denervated and stretched fast muscle under HS. These results suggest that the expression of alpha-B-crystallin is dynamically related to the muscle plasticity.