title: Activity of mu- and m-calpain in regenerating fast and slow twitch skeletal muscles.
abstract: Calpains--non-lysosomal intracellular calcium-activated neutral proteinases, form a family consisting of several distinct members. Two of the isoenzymes: mu (calpain I) and m (calpain II) responded differently to the injury during complete regeneration of Extensor digitorum longus (EDL) muscle and partial regeneration of Soleus muscle. In the crushed EDL the level of m-calpain on the 3rd and 7th day of regeneration was higher than in non-operated muscles, whereas the activity of this calpain in injured Soleus decreased. The level of mu-calpain in EDL oscillated irregularly during regeneration whereas in Soleus of both injured and contralateral muscles its level rapidly rose. Our results support the hypothesis that m-calpain is involved in the process of fusion of myogenic cells whereas mu-calpain plays a significant but indirect role in muscle regeneration.
authors.affiliation: Department of Cytology, Institute of Zoology, University of Warsaw, Poland. jmlabo@plearn.edu.pl
authors.forename: J
authors.initials: J
authors.lastname: Moraczewski
authors.forename: E
authors.initials: E
authors.lastname: Piekarska
authors.forename: M
authors.initials: M
authors.lastname: Zimowska
authors.forename: M
authors.initials: M
authors.lastname: Sobolewska
mesh_terms: D000818:Animals; D002154:Calpain / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007527:Isoenzymes; D002154:Calpain