Figure 7.

MITF regulates STIM1 expression in primary human melanocytes.A, pellet pictures of primary human melanocytes transfected with either siNT or siMITF (N = 3). B, Western blot analysis for MITF and STIM1 expression upon MITF silencing as compared to nontargeting control siRNA in primary human melanocytes (N = 3). C, densitometric quantitation of MITF levels in siNT and siMITF condition in primary human melanocytes (N = 3) D, densitometric quantitation of STIM1 levels in siNT and siMITF condition in primary human melanocytes (N = 3). E, representative Ca²⁺ imaging trace of siNT where “n = 100” denotes the number of cells in that particular trace stimulated with 2 μM thapsigargin (Tg) in Ca²⁺-free buffer followed by restoration of 2 mM extracellular Ca²⁺. F, representative Ca²⁺ imaging trace of siMITF where “n = 100” denotes the number of cells in that particular trace stimulated with 2 μM thapsigargin (Tg) in Ca²⁺-free buffer followed by restoration of 2 mM extracellular Ca²⁺. G, the extent of SOCE was calculated from 295 siNT and 240 siMITF primary human melanocytes, which were imaged from three independent experiments (“n = x, y” where “x” denotes total number of cells imaged and “y” denotes number of traces recorded). H–K, dot plots showing mRNA expression correlation analysis between MITF and STIM1/TYR/DCT or Gp100 in human sun-exposed skin tissue samples. “R” signifies value of Pearson’s correlation coefficient for each correlation analysis. Data presented are mean ± S.E.M. For statistical analysis, one sample t test was performed for panel C and D, and paired student’s t test was performed for panel G using GraphPad Prism software. Here, ∗p < 0.05; ∗∗∗p < 0.001. DCT, Dopachrome Tautomerase; MITF, Microphthalmia-associated transcription factor; STIM1, Stromal Interaction Molecule1; SOCE, store-operated Ca2+ entry.