Histochem Cell Biol, 2009; 132(4): 383-94, PMID: 19644701
Atypical fast SERCA1a protein expression in slow myofibers and differential S-nitrosylation prevented by exercise during long term bed rest.
Year: 2009
Salanova M, Schiffl G, Blottner D
Department of Vegetative Anatomy, Center of Space Medicine Berlin, Neuromuscular Group, Charite Universitatsmedizin Berlin, Campus Benjamin Franklin, Arnimallee 22, Berlin 14195, Germany. michele.salanova@charite.de
Abstract
We monitored changes in SERCA isoform specific expression and S-nitrosylation in myofibers of lower limb soleus (SOL) and vastus lateralis (VL) muscle biopsies before and after 60 days of voluntary long term bed rest (BR) without (BR-CTRL group, n = 8) and with exercise countermeasure (BR-EX group, n = 8). Before BR, a typical myofiber type-specific distribution of fast and slow SERCA1/2a isoforms was seen. After BR, a subpopulation (approx. 15%) of slow myofibers in BR-CTRL additionally expressed the fast SERCA1a isoform which was not seen in BR-EX. After BR, SERCA1a S-nitrosylation patterns analyzed by the biotin-switch assay decreased in disused SOL only but increased in both muscles following exercise. Differential SERCA1a S-nitrosylation and SERCA1a/2a co-expression in subsets of slow myofibers should be considered as signs of an altered cytosolic Ca(2+) homeostasis following chronic muscle disuse. Exercise preserved myofiber type-specific SERCA1a expression and S-nitrosylation in VL and SOL in a different way, suggesting muscle-specific responses to the countermeasure protocol applied during bed rest.Keywords: BBR1
GID: 3018; Last update: 05.08.2012
