title: Differences in mRNA expression of calpains, calpastatin isoforms and calpain/calpastatin ratios among bovine skeletal muscles.
abstract: Messenger RNA (mRNA) expression of calpain-1 (µ-calpain), -2 (m-calpain), -3 (p94), small subunit (calpain-4; 28 kDa), and three types of calpastatin (CSTN) isoform were investigated for 10 skeletal muscles of Holstein cattle by real-time and/or semi-quantitative reverse transcription polymerase chain reaction. Noticeably, effect of muscle type was observed on 28 kDa expression (P < 0.001) with a tendency of higher 28 kDa expression in myosin heavy chain (MyHC)-2x-rich muscles compared to MyHC-slow-rich muscles. The CSTN-I and -III expression in Longissimus thoracis (LT) showed the lowest value among the muscles tested. Moreover, 28 kDa/CSTN-I ratio was higher in the diaphragm (DP), psoas major (PM), and LT than those in the lingual muscles (TN), masseter (MS) and pectoralis (PP) (P < 0.05). Calpain-1/CSTN I, calpain-2/CSTN I in LT and PM were higher than that in TN (P < 0.05). Calpain-3/CSTN-I and -III in LT and/or PM showed higher values than that in TN (P < 0.05). These results indicated that the calpain and CSTN expressions are regulated by muscle type, suggesting especially by muscle fiber type. Calpains/CSTN-I ratios, especially 28 kDa/CSTN-I, may account for higher extent of post mortem proteolysis previously observed in LT and PM muscles.
authors.affiliation: Meat Protein Research Team, National Institute of Livestock and Grassland Science, Tsukuba, Ibaraki, Japan. muros@affrc.go.jp
authors.forename: Susumu
authors.initials: S
authors.lastname: Muroya
authors.forename: Kate E
authors.initials: KE
authors.lastname: Neath
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Nakajima
authors.forename: Mika
authors.initials: M
authors.lastname: Oe
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shibata
authors.forename: Koichi
authors.initials: K
authors.lastname: Ojima
authors.forename: Koichi
authors.initials: K
authors.lastname: Chikuni
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000032:analysis* / Q000235:genetics; D002154:Calpain / Q000032:analysis* / Q000235:genetics; D002417:Cattle / Q000378:metabolism*; D005260:Female; D007527:Isoenzymes / Q000032:analysis / Q000235:genetics; D018482:Muscle, Skeletal / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis*
chemical_list: D002135:Calcium-Binding Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; C033668:calpastatin; D002154:Calpain