Regulation Of Intracellular Calcium (session 2) Flashcards
What is the extracellular [Ca2+]?
Approx 1-2 x 10-3 M
What is the cytoplasmic [Ca2+]?
Approx 1 x 10-7 M
What is the ER/SR [Ca2+]?
Approx 2-3 x 10-4 M
What causes an increase in cytoplasmic Ca2+?
Movement of Ca2+ across plasma membrane
Release of Ca2+ from ER/SR
What decreases cytoplasmic Ca2+ conc?
Relative impermeability of plasma membrane to Ca2+
Pumps and transporters that move Ca2+ out of cytoplasm
Ca2+ ‘buffer’ proteins (Ca2+ binding proteins)
Describe the mechanisms that decrease [Ca2+]
ATP-dependent mechanisms:
- Plasma membrane Ca2+ ATPase (PMCA)
- SR/ER Ca2+ ATPase (SERCA)
Transporter mechanisms:
1. Na+, Ca2+ exchanger (NCX)
Describe the mechanisms that increase [Ca2+]
Ca2+ movement across plasma membrane (influx)
- Voltage operated Ca2+ channels (VOCC)
- Ligand gated ion channels (LGIC)
Ca2+ movement out of ER/SR (release)
- Ca2+ induced Ca2+ release (CICR)-ryanodine receptors
- IP3R