Cell Signaling 2

Question 1

Refresh: fill in the blanks.

Answer 1

Question 2

What exactly does cholera toxin do

Answer 2

Inactivates GTPase, meaning persistent increase of camp -> increase of PKA -> increase OPEN CFTR -> increase in fluid secretion.

Question 3

What is oxytocin?

Answer 3

Hormone that stimulates smooth muscle construction in the uterus(during childbirth) and in the breast (during lactation).

Question 4

Test: fill in the blanks and explain how oxytocin causes contractions.

Answer 4

The oxytocin receptor(G protein coupled signaling) increases calcium levels, which is what signals for contractions.

Question 5

What does Gq do?

Answer 5

Activates phospholipase C (release of Ca++ from intercellular stores)

Question 6

vey big test: explain boxes 1-5

Answer 6

Question 7

What does -lipase mean. (Ex. Phospholipase)

Answer 7

Cleaves a lipid.

Question 8

What does Phospholipase C do?

Answer 8

Cleaves a membrane phospholipid to make second messenger: IP3 (and DAG)

Question 9

What does IP3 do? What is it?

Answer 9

IP3 is a second messenger that releases calcium from internal calcium stores.

Question 10

What does Efferent mean?

Answer 10

Going away from.

Question 11

What are the two neuron pathways? What do they supply/do?

Answer 11

1. Somatic efferent neurons: they signal skeletal muscle cells.
2. Autonomic efferent neurons: they signal everything else.

Question 12

What do somatic efferent neurons do?

Answer 12

Innervate skeletal muscle.
(Innervate means to supply with nerves)

Question 13

What do autonomic efferent neurons do?

Answer 13

Innervate everything else that somatic efferent neurons don’t do.
(Smooth muscle, cardiac muscle, glands…)

Question 14

Where are Nicotinic acetylcholine receptors found?

Answer 14

Neuromuscular junction and in autonomic ganglia.

Question 15

Nicotinic AChRs are what type of receptor? And is it a fast or slow synaptic transmission?

Answer 15

Ligand-gated ion channels.
Fast synaptic transmission.

Question 16

Test: fill in the blanks:

Answer 16

Question 17

What do adrenergic receptors bind with? Hint: 2 things.

Answer 17

Epinephrine and norepinephrine.

Question 18

What is Norepinephrine (NE)? Describe its pathway.

Answer 18

The neurotransmitter released by sympathetic postganglionic neurons.

Question 19

What is epinephrine (E)? Describe its pathway.

Answer 19

A hormone released by the adrenal medulla.

Question 20

One signaling molecule, combined a different types of receptors. Norepinephrine is a great example. We know (we should at least) that norepinephrine binds to adrenergic receptors in the sympathetic pathway, but what does it bind to in the parasympathetic pathway? (2)

Answer 20

Nicotinic receptors in the parasympathetic ganglia.
Muscarinic receptors to its “target”. (This one is a GPCR, meaning it’s slow synaptic transmission).

Question 21

What type of transmission do GPCR’s mediate? (Fast or slow?)

Answer 21

Slow synaptic transmission.

Question 22

Test: fill in the blanks and know the last one!

Answer 22

Question 23

Define what an agonist is.

Answer 23

A drug that stimulates a receptor. (Behaves like an endogenous ligand as it binds an activates the receptor, but it’s not a natural ligand.)

Question 24

Define what an endogenous ligand is.

Answer 24

The natural ligand that binds/stimulates a receptor.

Question 25

Define what an antagonist is.

Answer 25

A drug/ligand that suppresses/blocks a receptor.

Question 26

Optional: define what a partial agonist is. And define what an inverse agonist is.

Answer 26

Question 27

What does PLA2 do? What is it?

Answer 27

It is an enzyme that releases arachidonic acid from membrane phospholipids.

Question 28

We know that PLA2 makes arachidonic acid, but what is the acids purpose?

Answer 28

Can be broken down by more enzymes, LOX (lipoxygenase) and COX(cyclooxygenase) to make liposoluble **paracrines**.

Question 29

Using this photo for help, what do Leukotrienes do? What about Prostaglandins? Where do these paracrines work?

Answer 29

Question 30

Knowing this information in the photo (or don’t look at it): NSAIDs is a drug that effect COX, what does it do want why? Also: Why do we have drugs that are Leukotriene antagonists? What do they do?

Answer 30

Question 31

What is JAK-STAT signaling?

Answer 31

Signal transduction via cytokine receptors. A category of catalytic receptors..

Question 32

Define what a catalytic receptor is.

Answer 32

Ligand binding directly activates an enzyme.

Question 33

Define what a cytokine is.

Answer 33

Signaling molecules that mainly affect immune cells.

Question 34

Describe the structure of JAK-STAT receptors.

Answer 34

JAK: “Just another Kinase”: a tyrosine kinase that has a stable association with the receptor. Usually two separate parts that come together (dimerization) when a ligand binds. Which the activates JAK, which then phosphorylates.

Question 35

How do cytokines differ from hormones?(2)

Answer 35

1. Produced by many different types of cells. 2. Synthesized on demand.

Question 36

Why should we care about cytokine signaling?

Answer 36

They activate macrophages!

Question 37

Define what a Macrophage is.

Answer 37

Cells that kill, pathogens, virally infected cells, and cancer cells.

Question 38

Define what DMARDs (disease-modifying anti-rheumatic drugs) are, and how they work.

Answer 38

They are drugs that reduce cytokine signaling and are effective in treating rheumatoid arthritis. The reason we need to reduce it signaling is because the macrophages that the cytokine activate damage and attack normal tissue in some diseased people. They are called DMARD because they slow the progression of the disease.

Question 39

Define latent

Answer 39

Existing but not yet developed.

Question 40

Test: explain the JAK-STAT pathway. (Try not to use the picture)

Answer 40

Question 41

For drugs that block cytokines from binding to the receptors, what size must they be and how must they be administered?

Answer 41

These drugs must be large proteins, and they must be infused.

Question 42

What size are JAK inhibitor drugs be and how are they administered? Why are these preferred to cytokine blockers?

Answer 42

Small molecules and orally taken. These inhibit, the JAK kinase to block cytokines signaling. They are preferred because they can be taken in pill form .