Chromogranins and the Quantum Release of Catecholamines
Chromogranins (Cgs) are the most abundant intravesicular proteins of chromaffin granules. Using Cgs knockout mice, we found that the lack of chromogranin A (CgA), chromogranin B (CgB) or both drastically reduce the vesicular content of catecholamines (CA), impair its accumulation in granules and largely affect the kinetics of exocytosis. Conversely, the overexpression of CgA induces the genesis of vesicles, increases their quantal content and even transforms non-secretory in cells capable to secrete substances. We conclude that Cgs contribute to a highly efficient system that directly mediates monoamine accumulation and regulates the exocytotic process.
KeywordsAmperometry Intracellular electrochemistry HEK293 L-DOPA Patch-amperometry PC12
Chromogranins A and B
Large dense core vesicle
Vesicular mono-amine transporter
Vesicular nucleotide transporter
Wild type animals
LC is the recipient of a fellowship from the Fundación CajaCanarias. This work is partially funded by the grant BFU2013-45253-P from the MINECO (Spain) to RB and JDM.
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