GPCRs and cAMP Flashcards
What are G protein-coupled receptors (GPCRs)?
The largest family of membrane proteins that are molecular targets for nearly 25% of clinically employed medicines.
Who won the 2012 Nobel Prize in Chemistry for work related to GPCRs?
Robert Lefkowitz and Brian Kobilka.
What physiological effects does GLP-1 have?
- Delay gastric emptying
- ↑ Insulin secretion
- ↑ ß-cell proliferation
- ↓ Glucagon secretion
- Improved glycemic control
- Increased insulin sensitivity
- Reduction in body weight
What is the main role of DPP4 in relation to GLP-1?
DPP4 is involved in the basis for type 2 diabetes treatments.
What are muscarinic acetylcholine receptors (mAChRs)?
A type of GPCR with subtypes including M1, M2, M3, M4, and M5.
Which muscarinic receptor is targeted by Tiotropium?
Muscarinic M3 receptor.
True or False: GPCRs are also known as ‘serpentine’ seven transmembrane domain receptors.
True.
What is the function of heterotrimeric guanine nucleotide binding proteins in GPCR signaling?
They are involved in signal transduction across the plasma membrane.
What is 3’5’ cyclic AMP?
The prototypic second messenger that is activated by adenylyl cyclases.
What happens when 3’5’ cyclic AMP levels are elevated in cells?
It activates a cascade of events initially by activating protein kinase A (PKA).
Fill in the blank: Adenylyl cyclases convert ATP into _______.
3’5’ cyclic AMP.
What is the role of cAMP phosphodiesterases?
They destroy 3’5’ cyclic AMP to return levels to basal and terminate the signal.
What are the four broad families of G protein subtypes based on function?
- Stimulate adenylyl cyclase
- Inhibit adenylyl cyclase
- Control ion channels
- Stimulate phospholipase C
Why are GPCRs considered a very ancient family?
They have evolved over time and are fundamental to many physiological processes.
What is the significance of GTP-and time-dependent signaling mechanisms in GPCRs?
They are essential for the regulation of physiological processes.
What occurs if 3’5’ cyclic AMP levels are not rapidly returned to basal levels?
Cells would not know that the initial signal had been terminated.
What type of drugs are selective for GPCRs?
Drugs like Tiotropium that target specific mAChRs.
What are the main take-home messages regarding GPCRs?
- They are the largest family of membrane proteins
- Major molecular targets of medicines
- Interact with heterotrimeric G proteins
- cAMP is a key secondary messenger.
