00:01
Okay, this question here says, consider the signaling cascade downstream of the epinephrine receptor shown below.
00:08
One of the results of epinephrine signaling is that glycogen is broken down to release glucose, and this process is known as glycogenolysis.
00:19
And it says, what would be the effect on overall extent of glucose production via this pathway in the following two scenarios, assume the same standardization of signaling in each case? so, remember that epinephrine is a peptide hormone, and it is going to bind to a g -protein coupler receptor.
00:36
So, as you can see here, it is binding to its receptor.
00:40
Then, you're going to have this transduction pathway.
00:44
Normally, what is going to happen after, or what happens after this interaction here is that, so, as it is called g -protein coupler receptor, it is a receptor that is attached to a g -protein inside of the cell.
00:56
So, what is going to happen is that the inactive g -protein is going to be activated.
01:02
And what happens after this, specifically the g -protein that is here is going to be a g, a stimulatory protein.
01:11
So, after this, g -protein has been activated, the alpha subunit of the g -protein is going to activate this enzyme here that is adenylyl cyclase.
01:22
So, you're going to activate your adenylyl cyclase.
01:25
And what is this molecule going to do? it is going to break down atp to cyclic amp levels.
01:32
So, the cyclic amp levels are going to increase.
01:36
And what is going to happen after this? well, this cyclic amp is the second messenger and it is going to activate the protein kinase a, as you can see here.
01:45
So, this protein kinase a is going to phosphorylate many substrates.
01:48
One of these is going to be this phosphorylase kinase.
01:52
So, it is going to phosphorylate the phosphorylase kinase and it is going to make it active.
01:59
And this phosphorylase kinase is the main enzyme that is responsible for glycogenolysis.
02:06
So, you're going to have active glycogen phosphorylase that is going to break down glycogen to glucose 1 -phosphate specifically.
02:15
But it's going to be later converted to glucose...