PKA phosphorylation of NCLX reverses mitochondrial calcium overload and depolarization, promoting survival of PINK1-deficient dopaminergic neurons Academic Article uri icon

abstract

  • Mitochondrial Ca(2+) overload is a critical, preceding event in neuronal damage encountered during neurodegenerative and ischemic insults. We found that loss of PTEN-induced putative kinase 1 (PINK1) function, implicated in Parkinson disease, inhibits the mitochondrial Na(+)/Ca(2+) exchanger (NCLX), leading to impaired mitochondrial Ca(2+) extrusion. NCLX activity was, however, fully rescued by activation of the protein kinase A (PKA) pathway. We further show that PKA rescues NCLX activity by phosphorylating serine 258, a putative regulatory NCLX site. Remarkably, a constitutively active phosphomimetic mutant of NCLX (NCLX(S258D)) prevents mitochondrial Ca(2+) overload and mitochondrial depolarization in PINK1 knockout neurons, thereby enhancing neuronal survival. Our results identify an mitochondrial Ca(2+) transport regulatory pathway that protects against mitochondrial Ca(2+) overload. Because mitochondrial Ca(2+) dyshomeostasis is a prominent feature of multiple disorders, the link between NCLX and PKA may offer a therapeutic target.

publication date

  • January 1, 2015