Alteration of expression of Ca ²⁺ signaling proteins and adaptation of Ca ²⁺ signaling in SERCA2 ^+/- mouse parotid acini

Purpose: The sarco/endoplasmic reticulum Ca ²⁺ -ATPase (SERCA), encoded by ATP2A2, is an essential component for G-protein coupled receptor (GPCR)-dependent Ca ²⁺ signaling. However whether the changes in Ca ²⁺ signaling and Ca ²⁺ signaling proteins in parotid acinor cells are affected by a partial loss of SERCA2 are not known. Materials and Methods: In SERCA2 ^+/- mouse parotid gland acinar cells, Ca ²⁺ signaling, expression levels of Ca ²⁺ signaling proteins, and amylase secretion were investigated. Results: SERCA2 ^+/- mice showed decreased SERCA2 expression and an upregulation of the plasma membrane Ca ²⁺ ATPase. A partial loss of SERCA2 changed the expression level of 1, 4, 5-tris-inositolphosphate receptors (IP ₃ Rs), but the localization and activities of IP ₃ Rs were not altered. In SERCA2 ^+/- mice, muscarinic stimulation resulted in greater amylase release, and the expression of synaptotagimin was increased compared to wild type mice. Conclusion. These results suggest that a partial loss of SERCA2 affects the expression and activity of Ca ²⁺ signaling proteins in the parotid gland acini, however, overall Ca ²⁺ signaling is unchanged.