1.3-CellSignaling

Question 1

What are the four methods of cell signaling?

Answer 1

1.Endocrine 2. Paracrine 3. Autocrine 4. Attachment

Question 2

What are the four important functions of cell signaling? REAL general..

Answer 2

Specificity, Amplification, Regulation, Integration

Question 3

What are the 4 signal transduction pathways we discussed?

Answer 3

1. G Protein (Adenylate Cyclase, PI) 2. Nitric Oxide 3. Cell-Surface 4. Intracellular

Question 4

Which transduction pathway is the target for 50% of pharmaceutical drugs?

Answer 4

G-Protein Pathway

Question 5

How many genes code for proteins involved in G-Protein pathways?

Answer 5

800 Genes!

Question 6

What are the 6 main steps to the general G-Protein pathway?

Answer 6

1. messenger binds to a GPCR (G-ProteinCoupledReceptor)–>2. Activated GPCR binds to alpha sub-unit->3. GDP disscociates->4. GTP binds to alpha sub-unti 5. Messenger leaves GPCR and alpha sub-unit binds to the affective receptor->6. GTP to GDP to get alpha off the target

Question 7

What happens in the Adenylate cyclase cAMP pathway? Namely: Type of GPCR; Name of Target Protein; the last two steps

Answer 7

GPCR: Beta-Adrenergic Receptor…..Target: Adenylate Cyclase. Next step: Adenylate cyclase converts ATP to cAMP. Last step: cAMP activates Protein Kinase A

Question 8

What happens to the catalytic subunits when Protein Kinase A is activated with cAMP?

Answer 8

The catalytic subunits leave the regulatory subunits

Question 9

What 2 things does the activated Protein Kinase A accomplish?

Answer 9

1.Phosphorylates Serine and Thyronine targets. 2. Stimulates transcription

Question 10

What type of GProteinCoupledReceptor is involved with neurotransmitter receptors linked to ion channels?

Answer 10

Muscarinic-Ach Receptor. This was Linton’s first/easiest example of G-Protein pathways

Question 11

How do we inactivate a G Protein receptor? (3 Steps) *The third step has a cool name protein!

Answer 11

1. Dissociate the Lignand 2. Phosphorylate the GPCR (cytoplasmic part) 3. bind Beta-Arrestin

Question 12

What are the three alternative ways to turn off a G Protein Pathway?

Answer 12

1.use a GTPase (get the GTP off the adenylate cyclase) 2. Stop cAMP activity (with a cAMP phosphodiesterase) 3. TIME (will degrade the GTP on its own!)

Question 13

What are the two diseases associated with the inability to terminate the Gprotein signal?

Answer 13

Cholera (cAMP opens ion channels=fatal diarrhea and Pertussis

Question 14

What are the two items activated via the PhosphoLipase C pathway?

Answer 14

1.PKC and 2. Calmodulin

Question 15

What is the main function of the Nitric Oxide pathway?

Answer 15

Relaxation of Smooth Muscle!

Question 16

What are the new/main players in the NitricOxide pathway?

Answer 16

1.Nitric Oxide 2.cGMP 3.ProteinKinaseG

Question 17

What is the main point of a Catalytic Receptor? What is the main example of a signaler that uses this?

Answer 17

That the receptor ALSO acts as an ENZYME! Example: Insulin works this way

Question 18

What type of ligands use intracellular receptors?

Answer 18

Hydrophobic! Steroids, Vitamins