Macroscopic consequences of calcium signaling in microdomains: A first-passage-time approach

Robert Rovetti, Kunal K. Das, Alan Garfinkel, and Yohannes Shiferaw

Phys. Rev. E 76, 051920 – Published 29 November 2007

Abstract

Calcium (Ca) plays an important role in regulating various cellular processes. In a variety of cell types, Ca signaling occurs within microdomains where channels deliver localized pulses of Ca activating a nearby collection of Ca-sensitive receptors. The small number of channels involved ensures that the signaling process is stochastic. The aggregate response of several thousand of these microdomains yields a whole-cell response which dictates the cell behavior. Here, we study the statistical properties of a population of these microdomains in response to a trigger signal. We use a first-passage-time approach to show analytically how Ca release in the whole cell depends on properties of Ca channels within microdomains. Using these results we explain for the first time the underlying mechanism for the graded relationship between Ca influx and Ca release in cardiac cells.

Received 25 January 2007

DOI:https://doi.org/10.1103/PhysRevE.76.051920

Authors & Affiliations

Robert Rovetti¹, Kunal K. Das², Alan Garfinkel³, and Yohannes Shiferaw⁴

¹Department of Biomathematics, University of California, Los Angeles, California 90095, USA
²Department of Physics, Fordham University, Bronx, New York 10458, USA
³Department of Medicine, University of California, Los Angeles, California 90095, USA
⁴Department of Physics and Astronomy, California State University, Northridge, California 91330, USA

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Issue

Vol. 76, Iss. 5 — November 2007

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Physical Review E

covering statistical, nonlinear, biological, and soft matter physics