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Biochemistry

Learn the toughest concepts covered in Biochemistry with step-by-step video tutorials and practice problems by world-class tutors

12. Biosignaling

PSP Secondary Messengers & PKC

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PSP Secondary Messengers & PKC

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So here we're going to briefly revisit our map of the lesson on bio signaling pathways, which is down below right here. And of course, we know that we've been exploring this map by exploring the left most branches first. And so we're currently talking about G protein coupled receptors and we've already covered the A dental it cycles. GPC are signaling pathway in terms of the stimulatory pathway which involves C and and P K. And we've also covered the inhibitory pathway as well as drugs and toxins that affect GPC are signaling. And we're currently exploring the Foss VOA nossa tied GPC are signaling pathway. And so now that we've introduced this fossil in a city, GPC are signaling pathway. In this video, we're going to continue to talk about the fossa Wannasathit GPC are signaling pathway as we talk more details about the secondary messengers such as I p three and D G calcium and Cal module in and also thean enzymes protein kinase C. And so let's go on and get started talking about these particular molecules. So here we're going to continue to talk about the phosphate and not so tied signaling pathway or PSP and more specifically, we're going to focus on the PSP secondary messengers and protein kindness C or P K. C. Now in this video, specifically, we're going to focus on the secondary messengers I, p three and D A. G. And so recall from our previous lesson videos that upon activation of the effect er enzyme protein light pay C or P L C, it's actually going to catalyze the hydraulics ISS of the substrate called pip to and so PLC hydrologist of Pip To is going to yield to secondary messengers and not settle triphosphate or i P three as well as diesel, glycerol or D A. G. Now recall that in a Seattle triphosphate or I P three is going to diffuse through the side assault to the end of plasmid ridiculous surface, where it's going to bind to calcium ion channels and trigger an increase in cytoplasmic calcium concentration. And so here you can see that the cytoplasmic calcium concentration is going to increase. Now recall that diesel glycerol or D A G is not going to diffuse through the cytoplasm. Instead, it's still going to be embedded and associated with the plasma membrane. And so it's going to remain associated with the plasma membrane and along with the release calcium from the previous step, it's going to activate the enzyme called protein kind A, C or P K. C. And so, if we take a look at our image down below, we can get a better visual of exactly what's happening here. And so notice over here on the far left, what we're showing you is our visual representation of the substrate Pip to and so pip to again is the substrate for the effect, er, enzyme protein like fossil like Pacey, which we have right here acting as the catalyst. And so what you can see is that PLC is going to cleave hydrolyzed Pip two into two secondary messengers which will see down below here is going to be I p three or a NAS. It'll triphosphate. And what you see up above right here is going to be the day so glycerol or the D a. G. Now, of course, I p three is going to diffuse through the cytoplasm so there will be site a Solich diffusion and it will diffuse all the way through, uh, the cytoplasm to reach the end of plasmid. Ridiculous a membrane. And so here you can see We're labeling it as the er membrane where the outside here represents the cytoplasm of the cell and down here represents the inside of the end of plasma particular, um, and notice that I p three again is going to diffuse through that cytoplasm until it binds to calcium ion channels embedded in the er membrane and will allow them to open up so that they can release calcium from the inside of the end of plasma. Ridiculous. And release it to the outside here of the Indo plasma ridiculous into the cytoplasm of the cell. And so this is going to lead to increased cytoplasmic calcium concentrations. And that's important to note here and so up above. If we take a look at what happens to die, so glycerol notice that it is still embedded in the plasma membrane of the cell, and so it can Onley diffuse laterally. And so lateral diffusion is what we're showing you here. And it will diffuse laterally to activate this other ends. I'm over here protein kinase C or P Casey, and so days so glycerol along with the calcium that was released down below in this step is going to again activate protein kinase C and that activation of protein kinase C is what's going to lead or helped lead to the cell response. And so now that we've got, um, or clear understanding of I p three and D A. G and our next video, we're going to discuss exactly more details about the calcium and how it forms a complex with Cal module in. So I'll see you guys in our next video.
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PSP Secondary Messengers & PKC

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So now that we've reviewed the two secondary messengers in a Seattle triphosphate or I P. Three and Isil Glycerol or D A. G and this video, we're going to focus on more on the calcium ion secondary messenger and the protein Cal module. In now, calcium ions or see a two plus are a common interest cellular signal that can trigger many different biochemical processes. And so recall in our previous lesson videos, we've seen that calcium can trigger processes that include muscle contractions as well as vesicles, Exocet, ASUs in neuron. However, what we have not yet mentioned in any of our previous lesson videos is that in order for calcium to affect its targets, calcium ions generally need to form a complex with another protein known as cow module in and so cow module in, As you can see, here is a protein that is commonly abbreviated as just see a M in this fashion like this. And so Cal Module in or C A M is, as its name implies, a calcium ion modulated side of solid protein, and so you can see calcium modulated is how Cal module in name originated, and so calcium module It just means that it is calcium dependent and so calcium modulated or dependent side of solid protein eyes going to activate a variety of different targets that could include protein kindnesses, which we know phosphor late other targets. And so Cal module in is again a calcium dependent or calcium modulated protein. And so Cal Module in is on Lee going to be activated when all four of its calcium binding sites are occupied by calcium. And so the active Cal module in calcium complex will bind to other target proteins in order to help activate those other proteins. And so, if we take a look at our image down below, uh, noticed that over here on the left, what we have is, ah, calcium ion. And over here, what we have is the Cal module in protein and noticed that the cow module in protein has these four specific calcium binding sites and so really went for calcium ions. Buying to Cal module in It creates the Cal module in calcium complex that we were just discussing. And so this is the active form of the calcium Cal module in complex. And so when it is active, it can actually bind to other target proteins such as kindness is like this one over here. In orderto help, activate them so you can see that the calcium call module and complex right here again combined to other proteins such as this blue protein kindness over here toe help activate it so that it can actually perform its function of phosphor, elated other targets and helping toe lead to the cell response. And so this year really concludes our introduction to calcium and cow module in and as we move forward in our course will be able to apply some of the concepts that we've learned here in some practice problems. So I'll see you guys in our next video.
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PSP Secondary Messengers & PKC

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So in this video, we're going to focus in on protein kaine A, C or P K C. And of course, we know that protein kind A C is commonly abbreviated as just p. K C. And as its name indicates, it is indeed a kindness. So we know that it's going to be an enzyme that fuss for late. It's substrates, but more specifically, protein kinase C or P K. C is a searing 39 kindness, which means that it fast for late Syrian 39 residues on its target proteins in order to alter the activity of those target proteins very, very similar to how the enzyme protein kindness A or PK, operated in our previous lesson. Videos now protein kinase C or P K C. Targets include enzyme sido skeletal proteins and nuclear proteins regulating gene expression. And so, ultimately, P K C activity can generate a wide variety of cell responses. And so if we take a look at our image down below, notice that P. K. C. Is right here. And so when P k C. Is associated with D A G, or die so glycerol as well as with calcium, then p k C takes on its active confirmation. And when P. K C. Is active, it can actually function as the kindness that it is so it can fuss for late. Its targets, such as enzymes like this one on, essentially alter their activity. So notice in this particular example, it's taking an inactive enzyme phosphors relating it here at this particular Syrian or three main residue, and that ultimately alters the activity of the enzyme so that it becomes active. And then this active protein can go on to generate the cell response. But again, be careful not to associate phosphor relation with activation, because phosphor relation can also sometimes lead to inactivation. And so here we're just showing it as one particular way that phosphor relation is leading toe activation. But don't forget that phosphor relation is just going to alter the activity, not necessarily lead to activation or inhibition. It will be a case by case basis, and so this year really concludes our video on Protein kind A, C or P K C, and we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you guys in our next video
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Problem

Which of the following enzymes does diacylglycerol recruit to the membrane and activate when bound?

5
Problem

Which of the following statements about calmodulin is TRUE?

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concept

PSP Secondary Messengers & PKC

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in this video, we're going to talk mawr. Details about the inactivation or the termination of the fossa innocent eyed GPC are signaling pathway. And so recall from our previous lesson videos that the GPS activity in the G protein Alfa sub unit will actually participate in the inactivation or the termination of the GPC are signaling pathway to help reset the pathway. However, in addition to the GPS activity of the G protein Alpha's up unit, there are also three other events that take place that also helped to inactivate or terminate the fossa. Innocent I GPC are signaling pathway. And so we've got these three other events number down below in our text. And so the first event is that I p three signaling effect can be turned off by decreasing the concentration of I P three uh in the cell. And the cell can decrease the concentration of i P three by using the enzyme called a NASA tall polly phosphate. Five phosphate tastes and so this enzyme and not settle Polly phosphate five Phosphate tastes is indeed a phosphate taste enzyme, as indicated by its name and recall that phosphate taste is remove phosphate groups from their substrates. And so and also tall Polly phosphate five Phosphate taste will remove a phosphate group from its substrate i p three. And so it will convert I P three into I. P two and I. P two does not release calcium from the end of plasma. Ridiculous. Um, like what I p three does. And so when Anna's it'll polly phosphate five foster taste convert i p three in tow I p two. It's actually helping to terminate these signals or inactivate the signal. Now the second event is going to be that p k CS or protein kindness es activity is going to be reversed by searing three and 19 phosphate cases as well, and so you can see that these foster taste is air going to play a big role in the inactivation or the termination of the signal. And again, phosphate cases are all about removing phosphate groups from their substrates. Now, the third event that helps to inactivate or terminate the signal is going to be that the cytoplasmic calcium concentrations, which were once increased, are now going to be decreased once again, back to its original state by the enzyme Sarko Plasmid Endo plasma, ridiculous calcium and 80 p s or the circa pump. What you might recall from our previous lesson videos is a P type 80 p. A s. And so, if we take a look at our image down below, we can see that we have the numbers one, 22 and three here that correspond with our image up above. And so, of course, you can see that here we have the Alfa sub unit of the G protein dissociating and activating the effect er enzyme protein like Pacey, which is going to again cleave its substrate pit two and two D A. G and I p three and I p three goes on to open up calcium channels in the end of plasma particular membrane to increase the calcium concentration in the cytoplasm. And, of course, that's going to lead Thio calcium binding Cal module in and activating protein kindnesses that lead to the cell response and then D A G, or dice of glycerol in the plasma membrane will laterally diffuse to activate protein. Kinda see along with the release, calcium and protein kinda see will act as a kindness to foster for late its targets again leading to the cell response. And so in this video again, we're focusing on the inactivation or the termination of that signal that leads to the cell response. And so the first event that we had talked about was the ability for an OSCE. It'll polly phosphate five phosphate tastes to essentially remove a phosphate group from I P three and convert I p three into I P two and I P two does not open up the calcium channel in the er membrane, and so this will help to terminate the signal and make sure that their cell responses not generated. The second event that we talked about was the addition or the activity of searing three inning phosphate aces, which will essentially re, um, remove or reverse the activity of the kindnesses that we have here. And then the third event that that is going to help terminate the signal is the circa pump what you can see down below right here. And that's helping to remove calcium from the cytoplasm and bring it right back into the end of plasma. Ridiculous, um, where it originally started. And so these three events, along with this event that you see here, which is the GTP hydraulics ISS of the Alfa C of sub unit are going to lead to the inactivation or the termination off this phosphor on assisted signaling pathway. And so this year concludes our lesson on the inactivation or termination of phosphate tenacity. GPC are signaling, and we'll be able to get some practice applying these concepts as we move forward in our course, So I'll see you guys in our next video.
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Problem

Protein Kinase C (PKC) is activated when bound by:

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Problem

What is the effector enzyme in the phosphoinositide signal transduction system?

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Problem

All of the following are functions served by phosphatidylinositol bisphosphate EXCEPT:

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