Fig. 2.

Cold stress overrides developmental downregulation of SLN expression. (A) Flow chart showing the gradual cold adaptation protocol for the neonates. (B) Body mass of neonates reared at 23°C (control) and gradually adapted to cold (cold adapted, CA) at 14 and 21 days post-natal age. The mice reared under gradual cold gained less body mass compared with the controls. (C,D) Top, western blot depicting SLN protein expression in quadriceps (C) and gastrocnemius (D); bottom, quantification of SLN levels normalized to α-tubulin shows a significant increase in quadriceps (C, P<0.0001, N=4) and in gastrocnemius (D, P<0.0001, N=4) of cold-reared mice. (E) Western blots depicting the expression levels of calcium-handling proteins SERCA1a and SERCA2a and a key regulator of energy metabolism AMP-activated kinase (AMPK). SERCA2a and phosphorylated (p-)AMPK expression are upregulated in cold-adapted mice. SERCA1a and calsequestrin expression are not affected by cold adaptation. *P<0.05, ***P<0.001.