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A computational investigation of the localized calcium dynamics
near a heterogeneous release siteMathematical Biology
|Speaker: ||Bori Mazzag, Humboldt State University|
|Location: ||2112 MSB|
|Start time: ||Mon, Feb 11 2008, 2:10PM|
Calcium is a very common messenger in many biological systems.
Calcium signaling inside cells is often mediated by calcium-gated
calcium channels such as inositol 1,4,5-triphosphate recpetors (IP3R) and
ryanodine receptors (RyR) located on internal calcium stores. There is a
characteristic isoform expression of IP3Rs and RyRs associated with
distinct cell types and this variation is thought to contribute to the
diversity of calcium signaling. Although many previous theoretical studies
have investigated the dynamics of localized calcium release sites, so far
all such studies focused on release sites consisting of identical channels.
We have extended an existing mathematical model to release sites with two
(or more) receptor types, each with its distinct channel kinetics.
Mathematically, the release site is represented by a transition probability
matrix that is coupled to a dynamically changing calcium domain. We use
this model to investigate the role of calcium inactivation in release site
dynamics, particularly in the termination of synchronous channel activity.
We show that the release site dynamics depend sensitively not only on the
fraction of channels without calcium inactivation, but their spatial