TY - JOUR
T1 - Modeling the dependence of the period of intracellular Ca2+ waves on SERCA expression
AU - Falcke, Martin
AU - Li, Yun
AU - Lechleiter, James D.
AU - Camacho, Patricia
PY - 2003/9/1
Y1 - 2003/9/1
N2 - Contrary to intuitive expectations, overexpression of sarco-endoplasmic reticulum (ER) Ca2+ ATPases (SERCAs) in Xenopus oocytes leads to a decrease in the period and an increase in the amplitude of intracellular Ca 2+ waves. Here we examine these experimental findings by modeling Ca2+ release using a modified Othmer-Tang-model. An increase in the period and a reduction in the amplitude of Ca2+ wave activity are obtained when increases in SERCA density are simulated while keeping all other parameters of the model constant. However, Ca2+ wave period can be reduced and the wave amplitude and velocity can be significantly increased when an increase in the luminal ER Ca2+ concentration due to SERCA overexpression is incorporated into the model. Increased luminal Ca 2+ occurs because increased SERCA activity lowers cytosolic Ca 2+, which is partially replenished by Ca2+ influx across the plasma membrane. These simulations are supported by experimental data demonstrating higher luminal Ca2+ levels, decreased periods, increased amplitude, and increased velocity of Ca2+ waves in response to increased SERCA density.
AB - Contrary to intuitive expectations, overexpression of sarco-endoplasmic reticulum (ER) Ca2+ ATPases (SERCAs) in Xenopus oocytes leads to a decrease in the period and an increase in the amplitude of intracellular Ca 2+ waves. Here we examine these experimental findings by modeling Ca2+ release using a modified Othmer-Tang-model. An increase in the period and a reduction in the amplitude of Ca2+ wave activity are obtained when increases in SERCA density are simulated while keeping all other parameters of the model constant. However, Ca2+ wave period can be reduced and the wave amplitude and velocity can be significantly increased when an increase in the luminal ER Ca2+ concentration due to SERCA overexpression is incorporated into the model. Increased luminal Ca 2+ occurs because increased SERCA activity lowers cytosolic Ca 2+, which is partially replenished by Ca2+ influx across the plasma membrane. These simulations are supported by experimental data demonstrating higher luminal Ca2+ levels, decreased periods, increased amplitude, and increased velocity of Ca2+ waves in response to increased SERCA density.
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U2 - 10.1016/S0006-3495(03)74580-9
DO - 10.1016/S0006-3495(03)74580-9
M3 - Article
C2 - 12944265
AN - SCOPUS:0041821608
SN - 0006-3495
VL - 85
SP - 1474
EP - 1481
JO - Biophysical Journal
JF - Biophysical Journal
IS - 3
ER -