1.
Cell Calcium
; 109: 102675, 2023 01.
Article
in English
| MEDLINE
| ID: mdl-36525777
ABSTRACT
NAADP (nicotinic acid adenine dinucleotide phosphate) is a second messenger, releasing Ca2+ from acidic calcium stores such as endosomes and lysosomes. PI(3,5)P2 (phosphatidylinositol 3,5-bisphosphate) is a phospho-inositide, residing on endolysosomal membranes and likewise releasing Ca2+ from endosomes and lysosomes. Both compounds have been shown to activate endolysosomal two-pore channels (TPCs) in mammalian cells. However, their effects on ion permeability as demonstrated specifically for TPC2 differ. While PI(3,5)P2 elicits predominantly Na+-selective currents, NAADP increases the Ca2+ permeability of the channel. What happens when both compounds are applied simultaneously was unclear until recently.