Signalling

Question 1

• Calcium signaling:
• Functions of Ca buffers? Creates distinct? Temporary what? What allow large quantities to be stored with out creating a gradient?
• Cytoplasmic Buffer?
• ER/SR Buffer?
• How does Ca enter the cell? (3)
• How does Ca exit ER/SR? (2)
• Routes to remove Ca? (3)

Answer 1

• Restrict spacial and temporal spread of Ca; signaling domain; storage of Ca; high capacity and low affinity
• Parvalbumin
• Calsaquestran
• Voltage gated channels, ligand gated (nACh glutamate), store operated channel
• IP3 receptors; RyR a little calcium stim. them
• Active transports with ATP into ECF or ER/SR; 3 Na/2 Ca exchanger; uniport into mito.

Question 2

• Calcium signaling:
• C2 Domain? Ex?
• EF hands? Ex? (4)
• Archtypical protein with EF hands?
• Archtypical protein with C2 domain?
• Synaptotagmin?

Answer 2

• Ca binding motif that binds Ca and phosphoserine; PKC in plasma membrane
• Parts of proteins that bind calcium; calmodulin, parvalbumin, calpain, troponin
• Calcium Effectors
• Associated with plasma membrane
• Ca binds to stick it to the membrane in synaptic vessicles to release neurotransmitters

Question 3

Cell Signalling:

• Types of detectors? (4)
• Typical cascade? (3)
• 2nd messenger examples? (4)
• Mechanisms for Signal Termination via:
  1. ) Extracellular signal molecule? (3)
  2. ) Receptor? (3)
  3. ) Protein binding/targeting? (2)
  4. ) Phos/ dephos?
  5. ) PDE?

Answer 3

• ligand gated ion channels, g protein coupled receptors, enzyme linked receptors (tyr-kin), nuclear receptors (TF’s activated by molecules)
• Receptor –> Intracellular signalling –> Target Proteins
• Ca, DAG, IP3, cAMP
  1. ) diffusion, inactivation, uptake into cell
  2. ) Desensitization, reduction of binding, internalization
  3. ) Decrease stimulus, degradation
  4. ) Deactivates
  5. ) cAMP to AMP

Question 4

Cell Signalling:

• Amplification possibilities? Ex?
• Nodes?
• Modules? Ex?
• Crosstalk prominant between? Why?

Answer 4

• 1.) Positive feedback loop (should be coupled with negative feedback loop); some Ca leads to more Ca
  2. ) Signaling Cascades: Depends on downstream effectors and how long upstream is active
• Points within pathway with multiple inputs and outputs
• Process signals together; includes protein complexes and feedback mechanisms; stove in kitchen
• Networks; complex regulation with relatively few molecules