lecture 12 Flashcards
What are the three types of plasma membrane receptors?
G protein-coupled receptors (GPCR)
Receptor tyrosine
Ion channel receptors (Ca^2+)
What is GPCR a receptor for?
epinephrine (adrenaline)
What is Receptor tyrosine (RTK) a receptor for?
Epidermal growth factor (EGF)
What is Ion channel receptors for?
neutrotransmitters
What is the phosphorylation cascade?
a sequence of signaling pathway events where one protein phosphorylates another, causing a chain reaction leading to the phosphorylation of thousands of proteins
What is the purpose of phosphorylation cascade
its a way to amplify the amount of signal from a small number of membrane proteins to many, many-second messengers
also gives cells flexibility and cross-talk between different signaling pathways
What is a ligand-gated ion channel?
When a plasma membrane receptor acts as a ‘gate’ for ions when the receptor changes shape
What does kinase do?
adds a phosphate group to a protein by removing one from adenosine triphosphate (ATP)
ATP -> ADP+ P protein
What does phosphatase do?
removes the phosphate group from the protein
P-protein -> protein + P
Is a protein with GDP active or inactive?
inactive
What happens during a GTP-GDP exchange?
GDP is removed and replaced with GTP. This causes a conformational change and results in as active protein
Is GTP active or inactive?
active
How do you deactivate GTP?
the 3rd phosphate group (or gamma) of the GTP is hydrolyzed and GDP is the product
What is Cyclic Adenosine Mono-Phosphate cAMP?
a common second messenger for G-protein-coupled receptors like those involved in taste, smell, metabolism, and mood
How can cAMp be formed?
ATP reaction
