L2- Drug Targets Flashcards
Which protein generates the resting membrane potential and consumes 40% of the body’s energy?
Sodium potassium ATPase
What’s the proportion of NA+ and K+ moved by the pump?
Na Na Na get out
K K come in
Do most ions spend most of the time open or closed?
Closed. So gating mechanisms are primarily concerned with how channel opening is controlled
Give five examples of ligand-gated ion channels?
- GABA-A
- Muscle nAChR
- Neuonal nAChR
- Glycine receptor
- Ionotropic glutamate receptors (from a different family, works slightly differently)
Cant remember why i put neuronal and muscle as two different ones..
How many subunits does a muscle nicotinic receptor have?
Five subunits.
2 alpha, 1 beta, 1 delta, 1 elipson (in foetal 1 gamma instead)
In muscle nicotinic receptor, how many subunits and what’s the structure of each subunit?
5 subunits. Each one has 4 TM domains.
TM2= lining of channel
Agonist binds to extracellular N terminus
Loop between TM3 and TM4 is a target for regulatory proteins
WHen do voltage gated channels open?
In response to changes in the membrane potential. Mostly they’re opened by the membrane depolarizing.
What are the 3 main classes of voltage gated channels?
Calcium channels,
Sodium channels
Potassium channels
WHat is the general structure of voltage gated channels?
Tetrameric, 4 subunits
Ion channel in centre
IN some of these channels the subunits may be linked into a single protein
Whats the strucutre fo the sodium and calcium channels?
Alpha sununit which makes up the channel. Smaller beta subunit which changes the properties.
Alpha is 4 pseudosubunits of 6 TMs with a membrane dipping domain between TM5 and 6
WHat controls the opening and closeing of the sodium and calcium channels?
TM4 is charged and acts as the voltage sensor.
When the membrane potential changes TM4 moves, opening and closing the channel.
WHat forms the lining of the calcium and sodium channels?
The membrane dipping domains come together to form the lining
