Fig 8. Summarized model showing the role of SERCA1b, in the regulation of calcium homeostasis.
Application of shRNA interfering with the SERCA1b expression resulted in a lower Ca2+-content of the SR and suppressed Ca2+-release into the myoplasm. In turn the activity of calcineurin- a calcium-dependent protein phosphatase which induces the translocation of the transcription factors of the NFAT family into the nucleus-was attenuated. The reduced proliferation and differentiation capability of myoblasts could therefore be attributed to a decreased activation of muscle specific genes under the control of NFAT.