Fig 2: Changes in the mRNA expression of distinct Ca2+ transport and binding proteins in PL and AM muscles during different periods. Histograms depicting (A) stromal interaction molecule-1 (STIM1) mRNA expression, (B) ORAI1 mRNA expression, (C) ryanodine receptor 1 (RyR1) mRNA expression, (D) leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) mRNA expression, (E) plasma membrane Ca2+ ATPase (PMCA)3 mRNA expression, (F) SR Ca2+ ATPase 1 (SERCA1) mRNA expression, (G) mitochondrial calcium uniporter (MCU) mRNA expression, (H) mitochondrial calcium uptake 1 (MICU1) mRNA expression, (I) mitochondrial calcium uptake 2 (MICU2) mRNA expression, and (J) calmodulin (CALM) mRNA expression in PL and AM muscles during different periods. PL, plantaris; AM, adductor magnus. SA, summer active group; PRE, pre-hibernation group; LT, late torpor group; IBA, inter-bout arousal group; ET, early torpor group; POST, post-hibernation group. Values are means ± SEM, n = 6–8. * (p < 0.05 and fold change = 2-fold), compared with SA; # (p < 0.05 and fold change = 2-fold) compared with PRE; & (p < 0.05 and fold change = 2-fold) compared with LT; $ (p < 0.05 and fold change = 2-fold) compared with IBA; + (p < 0.05 and fold change = 2-fold) compared with ET.

Fig 3: Changes in Pearson correlation coefficients of ORAI1/STIM1 in PL and AM muscles during different periods. (A) Representative fluorescence images in PL and AM muscles during different periods. 800× magnification, scale bar = 100 µm. (B) Histogram depicting Pearson correlation coefficients of ORAI1/STIM1 in PL and AM muscles during different periods. PL, plantaris; AM, adductor magnus. SA, summer active group; PRE, pre-hibernation group; LT, late torpor group; IBA, inter-bout arousal group; ET, early torpor group; POST, post-hibernation group. Values are means ± SEM, n = 6–8. * p < 0.05 and *** p < 0.001 compared with SA; # p < 0.05 compared with PRE; & p < 0.05 compared with LT; $ p < 0.05 and $$ p < 0.01 compared with IBA.

Fig 4: Real-time quantitative reverse transcription-polymerase chain reaction for Orai1. Upregulation of Orai1 mRNA expression was observed in human oral cancer cell lines (Ca9-22, and OECM-1) as compared with the primary culture of normal human oral keratinocytes (HOK) (*P < 0.05). Upregulation of Orai1 mRNA expression was observed in human oral cancer cell lines (Ca9-22, and OECM-1) as compared with the human oral premalignant cell line (DOK) (?P < 0.05). Upregulation of Orai1 mRNA expression without statistical significance was observed in DOK as compared with HOK. Results were normalized by the level of ß-actin & expressed as fold change relative to HOK & DOK respectively. Bars represent mean ± standard error of the mean.

Fig 5: Changes in the protein expression of distinct Ca2+ transport and binding proteins in PL and AM muscles during different periods. Histograms depicting (A) representative Western blot images of STIM1, ORAI1, RyR1, LETM1, PMCA3, SERCA1, MCU, MICU1, and CALM in PL and AM muscles during different periods. Histograms depicting (B) STIM1 protein expression, (C) ORAI1 protein expression, (D) RyR1 protein expression, (E) LETM1 protein expression, (F) PMCA3 protein expression, (G) SERCA1 protein expression, (H) MCU protein expression, (I) MICU1 protein expression, and (J) CALM protein expression in PL and AM muscles during different periods. PL, plantaris; AM, adductor magnus. SA, summer active group; PRE, pre-hibernation group; LT, late torpor group; IBA, inter-bout arousal group; ET, early torpor group; POST, post-hibernation group. Values are means ± SEM, n = 6–8. * p < 0.05, ** p < 0.01, and *** p < 0.001 compared with SA; # p < 0.05, ## p < 0.01, and ### p < 0.001 compared with PRE; & p < 0.05 compared with LT; $ p < 0.05 and $$ p < 0.01 compared with IBA; ++ p < 0.01 compared with ET.