Specific mitochondrial functions in separate sub-cellular domains of pancreatic acinar cells

Petersen, Ole Holger ORCID: https://orcid.org/0000-0002-6998-0380 2012. Specific mitochondrial functions in separate sub-cellular domains of pancreatic acinar cells. Pflugers Archiv European Journal of Physiology 464 (1) , pp. 77-87. 10.1007/s00424-012-1099-6

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Abstract

The pancreatic acinar cell synthesizes many digestive proenzymes, which are packaged into secretory (zymogen) granules and secreted by exocytosis upon the action of the neurotransmitter acetylcholine, released from vagal nerve endings, or the hormone cholecystokinin. These secretagogues mobilize Ca2+ from internal stores and thereby create the cytosolic Ca2+ signals that control exocytosis. Exocytosis requires Ca2+, Mg2+ and ATP. Mg2+ is present in millimolars concentration throughout the cytosol, but high cytosolic Ca2+ concentrations need to be created in the local domains near the apical plasma membrane. A special group of mitochondria surrounding the apical granular area play a crucial role in confining cytosolic Ca2+ elevations to this part of the cell by acting as a Ca2+ buffer barrier. The Ca2+ uptake into these mitochondria during apical Ca2+ spiking stimulates mitochondrial ATP synthesis. ATP is also required for Ca2+ extrusion via the plasma membrane Ca2+ pumps, mainly located in the apical area, as well as for Ca2+ reuptake into the endoplasmic reticulum. Because Ca2+ extrusion occurs during Ca2+ spiking, there is a need for compensatory Ca2+ entry via store-operated Ca2+ channels. Sub-plasmalemmal (peripheral) mitochondria play an important role in supporting both store-operated Ca2+ entry at the base as well as the subsequent Ca2+ pumping into the endoplasmic reticulum. A third group of mitochondria surround the nucleus. They protect the nucleus against unwarranted Ca2+ signals generated elsewhere and are capable of confining Ca2+ signals primarily generated inside the nucleus to this part of the cell.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences Systems Immunity Research Institute (SIURI)
Subjects:	R Medicine > RC Internal medicine
Uncontrolled Keywords:	Mitochondria; Calcium; ATP; Pancreatic acinar cell; Microdomains
Publisher:	Springer
ISSN:	0031-6768
Last Modified:	20 Oct 2022 09:36
URI:	https://orca.cardiff.ac.uk/id/eprint/32589

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