L3 - How Drugs Work - Part 2 Flashcards
1
Q
how does direct opening of ion channels work?
A
- in this case receptor protein is an ion channel
- protein that forms a pore in plasma membrane through which a specific type of ion can pass
- open/closed depending of the presence of the specific agonist
- binding of agonist results in a conformation change in the protein, which then opens
- ions flow through channel down conc gradient
2
Q
for the agonist acetylcholine, what is the recptor and the channel
A
- receptor
- nicotinic chlonergic
- channel
- opens cation channels
- mainly Na+
3
Q
How do enzyme receptors work
A
- mainly transmembrane proteins which often psses enzyme activity
- they have a ligand binding domain on the outer face of the plasma membrane
- also have a catalytic or enzymatic domain of the inner face of the plasma membrane
- strimulation of this type of receptor by an agonist increases the receptors catalytic activity
4
Q
domain
A
a distinct region of a complex molecule or structure
5
Q
tyrosine kinase receptors
A
- class of enzyme-linked receptors
- activation of the recptor by the agonist causes the trasnfer of a phosphate group onto specifc amino acids in the recptor itself
- this results in the recruitment of proteins from the cytosol
- become ‘scaffolded’ to the receptor
- this scaffold transmits the signalling information to the cell
6
Q
what type of recptor is the insulin receptor, what is the agonist, what physiological effects does it have, what disease does it treat
A
- tyrosine kinase receptor
- agonist is insulin
- physiological effect is glucose uptake
- disease is diabetes
7
Q
What are the 3 protein components of G protein-coupled receptor signalling
A
- 7 transmembrane receptor
- G portein (‘switch)
- GTP bound = active/on
- GDP bound= inactive/off
8
Q
What are GTP and GDP
A
- GTP
- guanosine triphosphate
- GDO
- guanosin diposphate
9
Q
G protein-coupled receptor singalling
what do components 1 and 2 do
A
- component 1
- each receptor (GPCR) binds its specific agonist
- e.g. glucagon binds to glucagon receptors
- component 2
- the G-protein (guanine nucleotide-binding regulatory protein) acts as a molecular switch
- the G-protein is associated with GTP, off when associated with GDP
- swithches itself and the system off
10
Q
G-protein
A
guanine nucleotide-binding regulatory protein
11
Q
what is the third component
A
- effector enzymes
- produce secondary messengers
12
Q
secondary messengers
A
- bind to specific target proteins within the cell to change the cell’s physiology
- usually protein kinases or IP3 receptors
13
Q
adenyl cyclase
A
- catalyses conversion of ATP (adenosine triphosphate) to cAMP (cyclic edenosine monophosphate)
14
Q
phospholipase C
A
- cuts the plasma membrane lipid phosphatidylinositol bisphosphate into DAG (diacylglycerol) and IP3 (inositol trisphosphate)
15
Q
cGMP phosphodiesterase
A
- effector enzyme
- breaks down cGMP (cyclic GMP, cyclic guanosine monophosphate)
