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IP3R at ER-mitochondrial contact sites: beyond the IP3R-GRP75-VDAC1 Ca2+ funnel

Published version
Peer-reviewed

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Article

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Authors

Atakba, Peace 

Abstract

Abstract Membrane contact sites (MCS) circumvent the topological constraints of functional coupling between different membrane-bound organelles by providing a means of communication and exchange of materials. One of the most characterised contact sites in the cell, is that between the endoplasmic reticulum and the mitochondrial (ERMCS) whose function is to couple cellular Ca2+ homeostasis and mitochondrial function. Inositol 1,4,5-trisphosphate receptors (IP3Rs) on the ER, glucose-regulated protein 75 (GRP 75) and voltage-dependent anion channel 1 (VDAC1) on the outer mitochondrial membrane are the canonical component of the Ca2+ transfer unit at ERMCS. These are often reported to form a Ca2+ funnel that fuels the mitochondrial low-affinity Ca2+ uptake system. We assess the available evidence on the IP3R subtype selectivity at the ERMCS and consider if IP3Rs have other roles at the ERMCS beyond providing Ca2+. Growing evidence suggests that all three IP3R subtypes can localise and regulate Ca2+ signalling at ERMCS. Furthermore, IP3Rs may be structurally important for assembly of the ERMCS in addition to their role in providing Ca2+ at these sites. Evidence that various binding partners regulate the assembly and Ca2+ transfer at ERMCS populated by IP3R-GRP75-VDAC1, suggesting that cells have evolved mechanisms that stabilise these junctions forming a Ca2+ microdomain that is required to fuel mitochondrial Ca2+ uptake.

Description

Keywords

Ca2+, GRP75, IP3 receptor, VDAC1, endoplasmic reticulum, membrane contact sites, mitochondria

Journal Title

Contact

Conference Name

Journal ISSN

2515-2564
2515-2564

Volume Title

Publisher

SAGE
Sponsorship
BBSRC (BB/T012986/1)

Version History

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2*
2023-10-18 10:39:10
Published version added
2023-05-27 00:30:44
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