Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
What are the 3 types of membrane receptors?
|
1. Ion channel linked (ionotropic)
2. GPCR (metabotropic) 3. Enzyme-linked |
|
What are 4 important characteristics of Ion channel-linked receptors?
|
1. It is a common gene family
2. The receptor directly gates an ion channel 3. These are major drug targets 4. Allows for RAPID signalling |
|
What are the 2 major ionotropic receptors?
|
-Nicotinic ACh receptors
-GABA receptor gated Cl channels |
|
What is GABA?
|
Gamma-aminobutyric acid
|
|
What is the nicotinic ACh receptor a channel for?
|
Pos cations - Na/K
|
|
What is the response of the cell when ACh binds to the nicotinic cholinergic ionotropic receptor?
|
Excitation - Depolarization
|
|
At what 3 sites is the nicotinic ACh receptor located?
|
-NMJ
-Autonomic PNS -CNS |
|
What is the GABA receptor an ion channel for?
|
Chloride
|
|
What is the cell response when GABA binds its receptor?
|
Hyperpolerization so Inhibition
|
|
Where is GABA found operating on these GABA receptors?
|
CNS
|
|
What is GABA then?
|
The main post synaptic inhibitory neurotransmitter in the CNS
|
|
What are 2 drugs that act via increasing the sensitivity of the GABA receptor? How do they work?
|
-Benzodiazepines
-Barbiturates -Allow lower concentrations of GABA to open the channel |
|
What is the main general feature of the GPCR?
|
It is a multi component system!
|
|
How many GPCRs are there in the large family of them?
|
~1000
|
|
What are 5 effects mediated by GPCRs?
|
-Neurotransmitters
-Light -Oderants -Hormones -Other extracellular messengers like growth factors and cytokines |
|
What makes up the receptor component of GPCRs?
|
A single 7-transmembrane protein
|
|
To what is the 7-TM protein coupled?
|
Heterotrimeric G proteins
|
|
What is a heterotrimeric G protein?
|
A Guanine nucleotide binding protein that links the ligand-activated GPCR to effector enzymes
|
|
So for the GPCR complex
-What provides specificity? -What does the transducing? -What is the effector? |
Specificity = 7TM receptor
Transducer = G-protein Effector = the catalytic component that generates a 2nd messenger |
|
How do Heterotrimeric G-proteins exist?
|
As molecular switches that cycle between two states
|
|
What are the 2 states that G-proteins cycle between?
|
Active - GTP bound
Inactive - GDP bound |
|
What do Heterotrimeric G proteins consist of?
|
3 proteins (subunits)
|
|
What are the 3 subunits that G proteins are composed of?
|
-G alpha
-G beta -G gamma |
|
What is the function of Ga?
|
Binds GTP/GDP, functions as a GTPase
|
|
What is the function of GB-Gy?
|
-Membrane anchor
|
|
How are heterotrimeric G proteins classified?
|
According to the type of G-a that is present in the trimer
|
|
What does Ga-s do?
|
Stimulates adenylate cyclase which activates PKA
|
|
What does Ga-i do?
|
Inhibits adenylate cyclase which inactivates PKA
|
|
What does Gaq do?
|
Activates phospholipase C which turns on PKC
|
|
What is the general feature to know about Enzyme-linked receptors?
|
They are a diverse group of receptors with different enzymatic activities.
|
|
What is the most important enzyme-linked receptor?
|
Tyrosine Kinase linked Receptors
|
|
What happens when ligand binds to a TKLR?
|
Dimerization
|
|
What follows dimerization of a TKLR?
|
Acivation by crossphosphorylation (auto) of the internal domains
|
|
What follows autophorphorylation of the cytoplasmic domains?
|
Intracellular signaling molecules bind
|
|
What gets regulated by the intracellular signalling molecules?
|
Cell proliferation and differentiation
|
|
What 3 ligand types utilize TKLRs to regulate cell proliferation and differentiation?
|
-Hormones
-Growth factors -Cytokines |
|
What disease process do TKLRs play an important role in?
|
Oncogenesis
|