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Thanh Cell Physiology Unit III > Calcium Signaling > Flashcards

Flashcards in Calcium Signaling Deck (11)
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1
Q

what are cytoplasmic Ca2+ ion buffers

A

Cytoplasmic Ca2+ buffers are proteins that bind to free Ca2+ in the cell.

2
Q

functions of cytoplasmic Ca2+ ion buffers

-how do they affect cytoplasmic calcium signals

A
  1. They restrict the spatial spread of free Ca2+ in order to localize it and control pathways
  2. Store Ca2+ until it can be properly transported.
3
Q

routes by which extracellular Ca2+ moves out of ER/SR (sarcoplasmic) into the cytoplasm

A
  1. recognition of Ca2+ in the cytoplasm by ryanodine receptors
  2. Triggers release of Ca2+ from ER/SR into cytoplasm
  3. Positive feedback mechanism –> more Ca2+ release
  4. IP3 receptors respond to IP3 to activate Ca2+ channels and stimulate Ca2+ influx into cytoplasm from the ER/SR.
4
Q

routes (pumps/exchangers) by which Ca2+ is moved out of the cytoplasm into the extracellular space

A
  1. Plasma membrane Ca2+ ATPase (PMCa ATPase)
    - a pump in the cell membrane
  2. or by Na/Ca exchangers (3 Na entry: 1 Ca exit)
5
Q

routes (pumps) by which Ca2+ is moved out of the cytoplasm into the the lumen of ER/SR

A

Sarco/Endoplasmic reticulum Ca2+ ATPase (SERCa ATPase)

6
Q

Important sources of Ca2+

A

(where it comes from)

-can overlap with sinks

7
Q

Important sink of Ca2+

A

(where it goes to)

-can overlap with sources

8
Q

EF hands

- example?

A

helix-loop-helix domains with 2 perpendicular alpha helices connected by a short loop that coordinates with Ca2+

-Calmodulin: protein made of 4 EF hands

9
Q

C2 domains

-example?

A

structural domains on proteins that coordinates with Ca2+ and target the protein to the plasma membrane

  • Protein Kinase A (PKA),
  • PKC
  • Synaptotagmin
10
Q

parvalbumin

A

cytoplasmic buffers: restricts spread of Calcium

11
Q

calsequestrin

A

high capacity ER/SR lumen buffers that store large quantities of calcium