Signal Transduction

Question 1

Signal transduction

Answer 1

Mechanisms by which signals detected at a cells surface are
transmitted into the cell’s interior, resulting in changes in the cell’s
behavior / gene expression

Question 2

Information flow during cell signaling

Answer 2

Question 3

Receptor-ligand interaction

Answer 3

Result in:
* Conformational changes
* Clustering
* Combination
* Binding affinities measured in Kd

Question 4

Agonist

Answer 4

synthetic
compound, similar
response
usually causes enhanced response

Question 5

Antagonist

Answer 5

inhibitor, block
response

Question 6

Switching receptors off

Answer 6

Question 7

Signal amplification

Answer 7

Question 8

Basic types of signaling pathways

Answer 8

• Ligand-gated ion channel
  -G protein-coupled receptor
• Enzyme-coupled receptor (receptor tyrosine kinase)
• Nuclear receptor

Question 9

GPCRs structure

Answer 9

• Ligand binding activates a particular G
  protein.
• G protein: guanine-nucleotide binding
  protein.
• Activated G protein binds to a target
  enzyme or channel, altering their
  activity
• E.g. olfactory receptors, β-adrenergic
  receptors, some hormone receptors,
  and opioid receptors

Question 10

Activation and inactivation of GPCRs

Answer 10

insert

Question 11

α and βγ Subunits and Signaling

Answer 11

• βγ subunit activates GPR kinases
• α subunits interact with adenylyl cyclase & phospholipase C
  insert

Question 12

G proteins and cAMP

Answer 12

• GSα subunit activates adenylyl cyclase
• adenylyl cyclase converts ATP → cAMP
• cAMP activates protein kinase A
• Phosphodiesterase breaks down cAMP

insert

Question 13

Protein kinase A activation
by cAMP

Answer 13

Insert
* PKA transfers phosphate from ATP to
Ser/Thr residues
* cAMP regulates PKA activity
* Detach reg unit from cat unit

Question 14

cell specific cAMP functions

Answer 14

Question 15

IP3 and DAG in Signaling

Answer 15

Insert
* Ligand-GPCR interaction → activation of Gq
* Gq activates phospholipase C (Cβ), generating
IP3 + DAG.
* IP3 activates the ligand-gated calcium channel,
the IP3 receptor channel → Ca2+ release.
* DAG activates PKC

Question 16

Calmodulin

Answer 16

Insert
Calmodulin mediates Ca2+-activated
processes

Question 17

Enzyme-Coupled Receptors

Answer 17

Question 18

Structure and Activation of a RTK

Answer 18

Receptor Tyrosine Kinase

Question 19

Receptor Serine-Threonine Kinases

Answer 19

Question 20

Signal transduction via RTKS

Answer 20

Question 21

Signal transduction via RTKS

Answer 21

Question 22

IP3 hormones + responses

Answer 22

Question 23

Growth factors and responses

Answer 23