Alteration of expression of Ca2+ signaling proteins and adaptation of Ca2+ signaling in SERCA2+/- mouse parotid acini.
OBJECTIVE
The sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), encoded by ATP2A2, is an essential component for G-protein coupled receptor (GPCR)-dependent Ca2+ signaling. However, whether the changes in Ca2+ signaling and Ca2+ signaling proteins in parotid acinar cells are affected by a partial loss of SERCA2 are not known.


METHODS
In SERCA2+/- mouse parotid gland acinar cells, Ca2+ signaling, expression levels of Ca2+ signaling proteins, and amylase secretion were investigated.


RESULTS
SERCA2+/- mice showed decreased SERCA2 expression and an upregulation of the plasma membrane Ca2+ ATPase. A partial loss of SERCA2 changed the expression level of 1, 4, 5-tris-inositolphosphate receptors (IP3Rs), but the localization and activities of IP3Rs were not altered. In SERCA2+/- mice, muscarinic stimulation resulted in greater amylase release, and the expression of synaptotagmin was increased compared to wild type mice.


CONCLUSIONS
These results suggest that a partial loss of SERCA2 affects the expression and activity of Ca2+ signaling proteins in the parotid gland acini, however, overall Ca2+ signaling is unchanged.
Choi
Jong-Hoon
JH
Department of Oral Medicine, Yonsei University College of Dentistry, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea.
Jo
Hae
H
Hong
Jeong Hee
JH
Lee
Syng-Ill
SI
Shin
Dong Min
DM
D000681:Amylases / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002217:Carbachol / Q000494:pharmacology; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010306:Parotid Gland / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology
D053496:Inositol 1,4,5-Trisphosphate Receptors; D002217:Carbachol; D000681:Amylases; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002118:Calcium