Cell Signaling 2 Flashcards
Refresh: fill in the blanks.
What exactly does cholera toxin do
Inactivates GTPase, meaning persistent increase of camp -> increase of PKA -> increase OPEN CFTR -> increase in fluid secretion.
What is oxytocin?
Hormone that stimulates smooth muscle construction in the uterus(during childbirth) and in the breast (during lactation).
Test: fill in the blanks and explain how oxytocin causes contractions.
The oxytocin receptor(G protein coupled signaling) increases calcium levels, which is what signals for contractions.
What does Gq do?
Activates phospholipase C (release of Ca++ from intercellular stores)
vey big test: explain boxes 1-5
What does -lipase mean. (Ex. Phospholipase)
Cleaves a lipid.
What does Phospholipase C do?
Cleaves a membrane phospholipid to make second messenger: IP3 (and DAG)
What does IP3 do? What is it?
IP3 is a second messenger that releases calcium from internal calcium stores.
What does Efferent mean?
Going away from.
What are the two neuron pathways? What do they supply/do?
- Somatic efferent neurons: they signal skeletal muscle cells.
- Autonomic efferent neurons: they signal everything else.
What do somatic efferent neurons do?
Innervate skeletal muscle.
(Innervate means to supply with nerves)
What do autonomic efferent neurons do?
Innervate everything else that somatic efferent neurons don’t do.
(Smooth muscle, cardiac muscle, glands…)
Where are Nicotinic acetylcholine receptors found?
Neuromuscular junction and in autonomic ganglia.
Nicotinic AChRs are what type of receptor? And is it a fast or slow synaptic transmission?
Ligand-gated ion channels.
Fast synaptic transmission.
Test: fill in the blanks:
What do adrenergic receptors bind with? Hint: 2 things.
Epinephrine and norepinephrine.
What is Norepinephrine (NE)? Describe its pathway.
The neurotransmitter released by sympathetic postganglionic neurons.
What is epinephrine (E)? Describe its pathway.
A hormone released by the adrenal medulla.
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)
Nicotinic receptors in the parasympathetic ganglia.
Muscarinic receptors to its “target”. (This one is a GPCR, meaning it’s slow synaptic transmission).
What type of transmission do GPCR’s mediate? (Fast or slow?)
Slow synaptic transmission.
Test: fill in the blanks and know the last one!
Define what an agonist is.
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.)
Define what an endogenous ligand is.
The natural ligand that binds/stimulates a receptor.
Define what an antagonist is.
A drug/ligand that suppresses/blocks a receptor.
Optional: define what a partial agonist is. And define what an inverse agonist is.
What does PLA2 do? What is it?
It is an enzyme that releases arachidonic acid from membrane phospholipids.
We know that PLA2 makes arachidonic acid, but what is the acids purpose?
Can be broken down by more enzymes, LOX (lipoxygenase) and COX(cyclooxygenase) to make liposoluble paracrines.
Using this photo for help, what do Leukotrienes do? What about Prostaglandins?
Where do these paracrines work?
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?
What is JAK-STAT signaling?
Signal transduction via cytokine receptors. A category of catalytic receptors..
Define what a catalytic receptor is.
Ligand binding directly activates an enzyme.
Define what a cytokine is.
Signaling molecules that mainly affect immune cells.
Describe the structure of JAK-STAT receptors.
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.
How do cytokines differ from hormones?(2)
- Produced by many different types of cells.
- Synthesized on demand.
Why should we care about cytokine signaling?
They activate macrophages!
Define what a Macrophage is.
Cells that kill, pathogens, virally infected cells, and cancer cells.
Define what DMARDs (disease-modifying anti-rheumatic drugs) are, and how they work.
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.
Define latent
Existing but not yet developed.
Test: explain the JAK-STAT pathway. (Try not to use the picture)
For drugs that block cytokines from binding to the receptors, what size must they be and how must they be administered?
These drugs must be large proteins, and they must be infused.
What size are JAK inhibitor drugs be and how are they administered? Why are these preferred to cytokine blockers?
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 .
