Signal Transduction

Question 1

What happens when a polar signal molecule is used?

Answer 1

Can’t cross lipid bilayer, binds to receptors on membrane triggers a signal cascade

Question 2

Describe the signal cascade?

Answer 2

Extracellular signal, receptor, intermendiates( kinases or enzymes) target then response

Question 3

What can epinephrine do?

Answer 3

Intestinal ,uncle relaxation
Release of lipase
Constrict blood flow
Increased heart rate
Skeletal muscle glycogen breakdown
Liver glycogen breakdown

Question 4

What do multi step Pathways allow for?

Answer 4

Amplification of signal and regulation of. Each step.

Question 5

What are the components of signaling pathways?

Answer 5

Extracellular singnals
Targets of signaling molecules
Membrane receptors.

Question 6

What a the various membrane receptors?

Answer 6

Ligand gated ion channels
GCPRS
RTKS

Question 7

Describe GCPRS

Answer 7

Made up of G proteins. Heterotomeric G protein. Activated by GTP and inactivated by GDP.
GIalpha activates adenylate cyclase
GS alpha is inhibitory.

Question 8

Describe RTKS

Answer 8

Recepor has built In Kinase which is activated by a signal
Requires receptor aggregation
Receptors halves cross phoshporylate
Signaling complex builds around activated RTK.
Can involve monomeric G protein.

Question 9

What is involved I. The cyclic amp cascade?

Answer 9

Second messenger cAMP
Produced by adenylate cyclase
Broken down by phosphodieterase

Question 10

What is the cyclic amp cascade?

Answer 10

Signal to GCPR 
Activate G alpha A (heterotrimeric G protein)
Activate adenylate cyclase 
Produce camp 
Activate protein kinase a(PKA)

Question 11

What is the membrane lipid that plays a role in signaling? What role does it play?

Answer 11

Phosphodidylinositol 2 phosphate (PIP2)

Second messenger

Question 12

How is PIP 2 made into a 2nd messenger?

Answer 12

It is cleaved I to phospholipase C to activate

Question 13

What is DAG and what does it do?

Answer 13

Diacgylcerol.

Activates protein kinase c (PLC)

Question 14

What happens after PIP2 Is cleaved?

Answer 14

DAG activates PKC
IP3 releases ca from ER storage via a ligand gated ion channel
Ca acts as a regulator
Binds to calmodulin leading to a conformational change
Ca/ calmodulin binds binds cam kinase

Question 15

What does the binding of cam kinase result in?

Answer 15

Release of neurtotransmitter vesicles in axon tip

Question 16

What are the two types of phospholipase c?

Answer 16

PLC- beta activated by heterotrimeric G protein

RTK- gamma activated by tyrosine kinase

Question 17

What is the IP3/DAG core pathway?

Answer 17

Signal
GCPR
GDP to GTP
heterotrimeric g alpha a
PLC3
IP3 to ca and calmodulin to activate cam kinase
DAG to PKA

Question 18

What is the pip2 pathway number 2

Answer 18

Used in cell survival signals
Two versions. GCPR and RTK
Pip3 activates PKB- protein kinase B

Question 19

What is the map kinase/ RTK receptor pathway?

Answer 19

Used in growth factors
Signal
RTK ( dimerization, cross phosphorylation and complex formation)
Activate monomeric G protein (remove GDP and add GTP)
Active at map KKK
Activate all the way to map K
Phoshporylate transcription factors 
Alter gene expression

Question 20

What are used for signaling?

Answer 20

Steroids and horomones

Non polar signals.