Modeling the dependence of the period of intracellular Ca2+ waves on SERCA expression

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Item Type:	Article
Title:	Modeling the dependence of the period of intracellular Ca2+ waves on SERCA expression
Creators Name:	Falcke, M., Li, Y., Lechleiter, J.D. and Camacho, P.
Abstract:	Contrary to intuitive expectations, overexpression of sarco-endoplasmic reticulum (ER) Ca(2+) 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 Ca(2+) release using a modified Othmer-Tang-model. An increase in the period and a reduction in the amplitude of Ca(2+) wave activity are obtained when increases in SERCA density are simulated while keeping all other parameters of the model constant. However, Ca(2+) wave period can be reduced and the wave amplitude and velocity can be significantly increased when an increase in the luminal ER Ca(2+) 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 Ca(2+) influx across the plasma membrane. These simulations are supported by experimental data demonstrating higher luminal Ca(2+) levels, decreased periods, increased amplitude, and increased velocity of Ca(2+) waves in response to increased SERCA density.
Keywords:	Biophysical Phenomena, Biophysics, Western Blotting, Calcium, Calcium-Transporting ATPases, Computer Simulation, Drug Dose-Response Relationship, Endoplasmic Reticulum, Kinetics, Confocal Microscopy, Mitochondria, Statistical Models, Oocytes, Messenger RNA, Sarcoplasmic Reticulum Calcium-Transporting ATPases, Time Factors, Animals, Xenopus
Source:	Biophysical Journal
ISSN:	0006-3495
Publisher:	Biophysical Society
Volume:	85
Number:	3
Page Range:	1474-1481
Date:	September 2003
Official Publication:	https://doi.org/10.1016/S0006-3495(03)74580-9
PubMed:	View item in PubMed

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