Oxysterol-binding protein related-proteins (ORPs) 5 and 8 regulate calcium signaling at specific cell compartments

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Pulli I, Lassila T, Pan G, Yan D, Olkkonen VM, Törnquist K
Förläggare: ELSEVIER SCI LTD
Publiceringsår: 2018
Tidskrift: Cell Calcium
Tidskriftsakronym: CELL CALCIUM
Volym: 72
Artikelns första sida, sidnummer: 62
Artikelns sista sida, sidnummer: 69
Antal sidor: 8
ISSN: 0143-4160


Abstrakt

Oxysterol-binding protein related-protein 5 and 8 (ORP5/8) localize to the membrane contact sites (MCS) of the endoplasmic reticulum (ER) and the mitochondria, as well as to the ER-plasma membrane (PM) MCS. The MCS are emerging as important regulators of cell signaling events, including calcium (Ca2+) signaling. ORP5/8 have been shown to interact with phosphatidylinositol-4,5-bisphosphate (PIP2) in the PM, and to modulate mitochondrial respiration and morphology. PIP2 is the direct precursor of inositol trisphosphate (IP3), a key second messenger responsible for Ca2+-release from the intracellular Ca2+ stores. Further, mitochondrial respiration is linked to Ca2+ transfer from the ER to the mitochondria. Hence, we asked whether ORP5/8 would affect Ca2+ signaling in these cell compartments, and employed genetically engineered aequorin Ca2+ probes to investigate the effect of ORP5/8 in the regulation of mitochondrial and caveolar Ca2+. Our results show that ORP5/8 overexpression leads to increased mitochondrial matrix Ca2+ as well as to increased Ca2+ concentration at the caveolar subdomains of the PM during histamine stimulation, while having no effect on the cytoplasmic Ca2+. Also, we found that ORP5/8 overexpression increases cell proliferation. Our results show that ORP5/8 regulate Ca2+ signaling at specific MCS foci. These local ORP5/8-mediated Ca2+ signaling events are likely to play roles in processes such as mitochondrial respiration and cell proliferation.


Nyckelord

caveolae, Endoplasmic reticulum, Mitochondria, ORP5, ORP8

Senast uppdaterad 2020-18-01 vid 03:37