Calcium Signaling

Question 1

What is the typical cytosolic concentration of calcium?

Answer 1

50 - 100 nM

Question 2

What is the typical concentration of calcium in the ER/SR?

Answer 2

2 mM

Question 3

List three cellular sources of calcium.

Answer 3

Endoplasmic/sarcoplasmic reticulum; nuclear envelope; mitochondria

Question 4

_____ and _____ are receptors that move calcium from the ER/SR to the cytoplasm.

Answer 4

Ryanodine and IP3

Question 5

________ channels open in response to the depletion of ER/SR calcium sources.

Answer 5

Orai1

Question 6

Secondary channels use the influx of _______ atoms to expel _____ atom.

Answer 6

Three sodium; one calcium

Question 7

Cytosolic calcium is buffered by _______, while ER/SR calcium is buffered by _________.

Answer 7

Parvalbumin; calsequestrin

Question 8

Calcium binding to the C2 domain of _______ induces association with the cell membrane.

Answer 8

Protein kinase C

Question 9

Three calcium ions bind to the C2A domain of ________ to cause vesicle fusion.

Answer 9

Synaptotagmin

Question 10

Calmodulin has four _____ that bind to calcium; each site has 5 oxygens.

Answer 10

EF-hands

Question 11

Relaxation (cessation of muscle contraction) is caused by ______.

Answer 11

Calcium binding to calcium-dependent potassium channels.

Question 12

Mutations in _______ cause familial catecholaminergic polymorphic ventricular tachycardia.

Answer 12

RyR2 (ryanodine receptor 2, the cardiac ryanodine receptor)