Quantification of the transport that underlies intracellular calcium signals

CECILIA VILLARRUEL; LORENA SIGAUT; MARIA LAURA PONCE; SILVINA PONCE DAWSON

Otro; Sistemas modelos en Ciencias Biológicas; 2014

Instituto de Investigación en Biomedicina de Buenos Aires-Partner Institute of the Max Planck Society (IBioBA-CONICET-MPSP).

The versatility of calcium as a signaling agent is based on the great diversity of spatio-temporal behaviors that its concentration can display inside cells. Its full comprehension requires the combination of observation and modeling.Optical techniques and fluorescent calcium dyes have provided a relatively non-invasive means to study the dynamics of intracellular calcium signals. Xenopus laevis oocytes are a model system in which an enormous variety of calcium signals have been observed, from localized signals to cellular waves.Using confocal microscopy and fluorescent calcium dyes we will quantify certain biophysical parameters that characterize the processes that determine the spatio-temporal dynamics of intracellular calcium. In particular it is important to know the calcium coefficient diffusion in cells and how its transport is affected by the presence of buffers -typically proteins-. In oocytes, the intracellular calcium signals are mediated by IP3 receptors (IP3Rs). The IP3Rs are channels of the endoplasmic reticulum membrane, that open when are bound to calcium and IP3. We will observe the distribution of IP3Rs in oocytes expressing the fusion protein GFP-IP3R and we will try to determine its diffusion rate and spatial distribution over the endoplasmic reticulum membrane.