NCLX is an essential component of mitochondrial Na+/Ca2+ exchange.
Mitochondrial Ca(2+) efflux is linked to numerous cellular activities and pathophysiological processes. Although it is established that an Na(+)-dependent mechanism mediates mitochondrial Ca(2+) efflux, the molecular identity of this transporter has remained elusive. Here we show that the Na(+)/Ca(2+) exchanger NCLX is enriched in mitochondria, where it is localized to the cristae. Employing Ca(2+) and Na(+) fluorescent imaging, we demonstrate that mitochondrial Na(+)-dependent Ca(2+) efflux is enhanced upon overexpression of NCLX, is reduced by silencing of NCLX expression by siRNA, and is fully rescued by the concomitant expression of heterologous NCLX. NCLX-mediated mitochondrial Ca(2+) transport was inhibited, moreover, by CGP-37157 and exhibited Li(+) dependence, both hallmarks of mitochondrial Na(+)-dependent Ca(2+) efflux. Finally, NCLX-mediated mitochondrial Ca(2+) exchange is blocked in cells expressing a catalytically inactive NCLX mutant. Taken together, our results converge to the conclusion that NCLX is the long-sought mitochondrial Na(+)/Ca(2+) exchanger.
Palty
Raz
R
Department of Physiology, and Zlotowski Center for Neuroscience, Ben-Gurion University of Negev, Beer-Sheva 84105, Israel.
Silverman
William F
WF
Hershfinkel
Michal
M
Caporale
Teresa
T
Sensi
Stefano L
SL
Parnis
Julia
J
Nolte
Christiane
C
Fishman
Daniel
D
Shoshan-Barmatz
Varda
V
Herrmann
Sharon
S
Khananshvili
Daniel
D
Sekler
Israel
I
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002998:Clonazepam / Q000031:analogs & derivatives / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000378:metabolism / Q000648:ultrastructure; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013841:Thiazepines / Q000378:metabolism
D019831:Sodium-Calcium Exchanger; D013841:Thiazepines; D002998:Clonazepam; C079032:CGP 37157; D012964:Sodium; D002118:Calcium