Second messenger heterogeneity in living cells measured with genetically encoded fluorescent indicators
Abstract number: S4.9-03
Pozzan T.
The idea that the cell cytoplasm is not a homogeneous container of saline solution is an established fact. Not only is the cell full of different organelles, but the cytoplasm itself is highly viscous and structured because of the high density of proteins and because of the presence of an intricate network of filamentous proteins, the so called cytoskeleton. Moreover, some second messengers have the intrinsic capacity of self-regeneration (e.g. the so-called Ca2+ induced Ca2+ release), while others (cyclic nucleotides) can be attacked and degraded by enzymes. Essentially three parameters are theoretically involved in the formation of local second messenger gradients: (i) localized site of generation; (ii) of degradation-accumulation; and (iii) diffusion rates of the molecule within the cytosol. A number of evidence has accumulated over the last decade on the importance not only of temporal aspects of second messenger-mediated signaling (e.g. waves and oscillations), but also of the importance of the subcellular heterogeneity of these molecules. In order to understand the functional importance of such heterogeneity it is compelling to monitor the dynamics of second messenger concentration in living cells with utmost spatial and temporal accuracy. I here discuss the more recent improvements obtained in our laboratory in the measurement of cellular Ca2+ and cAMP dynamics not only in living cells, but also in live animals and I discuss a few examples of how the highly structured organization of the molecular machinery leading to the production and degradation (sequestration) of the second messengers can lead to a dramatic heterogeneity in their subcellular distribution.
| Date: |
01/08/2007
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| Time: |
00:00-00:00
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| Session name: |
XXIst ISTH Congress |
| Subject: |
4.9 Membranes: transport and signaling |
| Location: |
Oxford, UK |
| Presentation type: |
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