caa a22 4500 605514526 CHVBK 20210128100705.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00360-014-0880-6 doi (NATIONALLICENCE)springer-10.1007/s00360-014-0880-6 Activity, abundance and expression of Ca2+-activated proteases in skeletal muscle of the aestivating frog, Cyclorana alboguttata [Elektronische Daten] [Beau Reilly, Rebecca Cramp, Craig Franklin] In most mammals, prolonged muscle disuse (e.g. bed-rest, limb casting or spaceflight) results in atrophy of muscle fibres which is largely due to unregulated proteolysis. Although numerous proteolytic pathways are known to participate in muscle disuse atrophy, recent evidence suggests that activation of Ca2+-dependent cysteine proteases (calpains) is required for disuse atrophy in limb skeletal muscles. In contrast to typical models of muscle disuse (humans and rodents), animals that experience natural bouts of chronic muscle inactivity, such as hibernating mammals and aestivating frogs, consistently exhibit limited or no change in skeletal muscle size. In the current study, we examined enzyme activity, protein abundance and gene expression levels of calpain isoforms in gastrocnemius muscle of the aestivating frog, Cyclorana alboguttata. We predicted that in aestivating C. alboguttata there would be a downregulation of the abundance, activity and gene expression of calpain 1 and calpain 2. In contrast to our hypothesis, there was no significant decrease in the enzyme activity levels or the relative protein abundances of calpain 1 and calpain 2. Similarly, gene expression assays (both qRT-PCR and RNA Seq data) indicated that calpains were unaffected by aestivation. Western blotting of ‘muscle-specific' calpain 3, which is consistently downregulated during atrophic conditions, indicated that this isoform is present in C. alboguttata muscle where it appears to be in its autolysed state. The absence of any increase in enzyme activity, protein and mRNA abundance of calpains in aestivators is consistent with the protection of gastrocnemius muscle against uncontrolled proteolysis throughout aestivation. Springer-Verlag Berlin Heidelberg, 2014 Calpain nationallicence Proteolysis nationallicence Atrophy nationallicence Aestivation nationallicence Calcium nationallicence Reilly Beau School of Biological Sciences, The University of Queensland, 4072, Brisbane, QLD, Australia aut Cramp Rebecca School of Biological Sciences, The University of Queensland, 4072, Brisbane, QLD, Australia aut Franklin Craig School of Biological Sciences, The University of Queensland, 4072, Brisbane, QLD, Australia aut Journal of Comparative Physiology B Springer Berlin Heidelberg 185/2(2015-02-01), 243-255 0174-1578 185:2<243 2015 185 360 https://doi.org/10.1007/s00360-014-0880-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00360-014-0880-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Reilly Beau School of Biological Sciences, The University of Queensland, 4072, Brisbane, QLD, Australia aut NATIONALLICENCE 700 1- Cramp Rebecca School of Biological Sciences, The University of Queensland, 4072, Brisbane, QLD, Australia aut NATIONALLICENCE 700 1- Franklin Craig School of Biological Sciences, The University of Queensland, 4072, Brisbane, QLD, Australia aut NATIONALLICENCE 773 0- Journal of Comparative Physiology B Springer Berlin Heidelberg 185/2(2015-02-01), 243-255 0174-1578 185:2<243 2015 185 360