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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.


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