Lecture 3: G-coupled protein receptors Flashcards
What are the components of a signalling pathway?
- Signal
- Receptor
- Transduction cascade
- Targets:
- Metabolic enzyme
- Gene regulator
- Cytoskeletal protein - Response:
- Altered metabolism
- Altered gene expression
- Altered cell shape or motility
What are G-coupled receptors?
Membrane-bound molecular switches.
They are the largest family of cell surface receptors (>800 in human genome)
Signal receptors for a wide range of molecules, including hormones and neurotransmitters.
About a third of all drugs used today work through GPCRs
How do G-coupled protein receptors work?
Ligand binding causes a conformational change, activating GEF domain, and in turn activates G proteins.
What large group of enzymes do G-coupled receptors belong to?
They belong to the family of GTPases.
What are the two distinct families of G proteins?
Heterotrimeric G proteins and “Small” G proteins.
What are heterotrimeric G proteins made up of? And what is their function?
What do GDP and GTP stand for?
GDP stands for Guanosine diphosphate and GTP stands for guanosine triphosphate.
What role do GDP and GTP perform in G protein function?
What happens when a substrate binds to G-coupled protein receptors?
It will activate the G-proteins,
What makes G-proteins so important?
What effects does caffeine have on the body?
A number of heterogeneous impacts take place:
- Caffeine inhibits cAMP phosphodiesterase
- Caffeine also inhibits acetylcholinesterase (long-term inhibition is very bad)
- Caffeine also facilitates binding of dopamine to its receptors.
- Acts as a non-selective antagonist for adenosine (which normally binds to adenosine receptors in the brain to promote lethargy and tiredness).
What are two main functions of cAMP?
cAMP signalling pathway can activate enzymes.
the cAMP signalling pathway can also activate genes.
How does cAMP need to do to produce most of its effects?
What is the Gq protein?
What is inositol triphosphate? (IP3)
