Bayraktar E, Bortolozzi M. Measuring Connexin Hemichannel Opening in Response to an InsP3-Mediated Cytosolic Ca
2+ Increase.
Methods Mol Biol 2024;
2801:189-197. [PMID:
38578422 DOI:
10.1007/978-1-0716-3842-2_14]
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Abstract
The opening of connexin hemichannels (HCs) expressed at the plasma membrane of mammalian cells is regulated by a number of physiological parameters, including extracellular and intracellular Ca2+ ions. Submicromolar variations of the cytosolic Ca2+ concentration ([Ca2+]c) are per se sufficient to trigger extracellular bursts of messenger molecules through connexin HCs, thus mediating paracrine signaling. In this chapter, we present a quantitative method to measure the opening dynamics of connexin HCs expressed in a single HeLa cell upon stimulation by a canonical InsP3-mediated [Ca2+]c transient. The protocol relies on a combination of Ca2+ imaging and patch-clamp techniques. The insights gained from our method are expected to make a significant contribution to understanding the structure-function relationship of connexin HCs. The protocol is also suitable to screen candidate therapeutic compounds to treat connexin-related diseases linked to HC dysfunction.
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