How cells keep [Ca]i low
All eukaryotic cells have PM Ca2+-ATPase
Excitable cells also have Na+/Ca2+ exchanger (NCX)
ER Ca2+-ATPase (against a high grad)
Mitochondrial high capacity (low affinity) pump
When [Ca]i very high (dangerous) levels (>10-5 M)
Inner mitochondrial membrane
Uses the electrochemical gradient generated during
electron-transfer of oxidative-phosphorylation