13.01.2013 Views

Calcium-Binding Protein Protocols Calcium-Binding Protein Protocols

Calcium-Binding Protein Protocols Calcium-Binding Protein Protocols

Calcium-Binding Protein Protocols Calcium-Binding Protein Protocols

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Deconvolution of <strong>Calcium</strong>-<strong>Binding</strong> Curves 25<br />

3<br />

Deconvolution of <strong>Calcium</strong>-<strong>Binding</strong> Curves<br />

Facts and Fantasies<br />

Jacques Haiech and Marie-Claude Kilhoffer<br />

1. Introduction<br />

Ca 2+ signaling is of paramount importance in intracellular communication<br />

of eukaryotic cells. Many external stimuli trigger a transient change in the<br />

cytosolic-free Ca 2+ concentration (in the form of a Ca 2+ wave or Ca 2+ oscillations).<br />

The internal Ca 2+ modulation is deciphered by Ca 2+ -binding proteins,<br />

which undergo conformational changes upon Ca 2+ -binding allowing them to<br />

act as enzymatic or protein modulators. These Ca 2+ -binding proteins have been<br />

well described in the past three decades (1–6). Calmodulin, an ubiquitous and<br />

multifunctional protein, is considered as the prototype of the Ca 2+ -binding protein<br />

family containing EF-hand domains (7–16). Because of its pivotal role in<br />

many Ca 2+ -dependent cellular events, the understanding of the mechanism of<br />

action of this protein at the molecular level has been the aim of several research<br />

groups. For such a study, four main points have to be tackled:<br />

• Description of the mechanism of Ca 2+ -binding to calmodulin;<br />

• Understanding of the conformational changes induced by Ca 2+ -binding;<br />

• Analysis of the interaction of calmodulin with the different targets; and<br />

• Deciphering the activation or the modulation of the calmodulin/target protein<br />

complexes.<br />

Calmodulin is a protein with four Ca 2+ -binding sites. In this chapter, we will<br />

describe how to deconvolute Ca 2+ -binding curves, with special emphasis on<br />

calmodulin Ca 2+ -binding curves.<br />

The mechanism of Ca 2+ -binding to calmodulin has been described since<br />

1973 and has been subject to many controversies. Therefore, we are going<br />

From: Methods in Molecular Biology, vol. 173:<br />

<strong>Calcium</strong>-<strong>Binding</strong> <strong>Protein</strong> <strong>Protocols</strong>, Vol. 2: Methods and Techniques<br />

Edited by: H. J. Vogel © Humana Press Inc., Totowa, NJ<br />

25

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!