Pattern Recognition Receptors (PRRs) - Video Tutorials & Practice Problems
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1
concept
Pattern Recognition Receptors
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in this video we're going to begin our lesson on pattern recognition receptors or PR ours. And so pattern recognition receptors are commonly abbreviated as P are ours. And so these pattern recognition receptors or PR ours are really just cell surface receptors of immune cells that are important for sensing and detecting signs of microbial invasion. Now as we'll learn moving forward in our course there are many different types of Pr ours and these different types of P. R. R. S all detect signs of microbial invasion. However different types of P. R. R. S will detect signs of microbial invasion in different areas of the cell. And so we'll be able to talk about this as we move forward in our course. Now notice down below we're showing you our map of the lesson on innate immunity on the left hand side. And notice already in our previous lesson videos we've talked about the first line defenses and we've also talked about the second line defenses and cells of innate immunity. And we've already started talking about the scanning systems that are important for detecting signs of microbes and so they serve somewhat as security cameras. So we've already talked about cell communication and now we're focusing on these pattern recognition receptors. Now moving forward in our course we're going to talk about several different types of pattern recognition receptors including toll like receptors or T. L. R. S. See tight leptin receptors or C. L. R. S. Nod like receptors or N. L. R. S. And rig like receptors or our LRS. And so we'll get to talk about all of these different types of pattern recognition receptors moving forward in our corpse now notice that all of these pattern recognition receptors are important for detecting signs of microbial invasion but they will detect signs of microbial invasion in different areas. And so what we mean by that is that some of the pattern recognition receptors or Pr. R. S are going to be P. R. R. Is found on the cell surface. And so these P R. R. Is found on the cell surface are important for detecting microbial components on the outside of the cell. And so notice that these P. R. R. S. These pattern recognition surface receptors that are on the cell surface are important for detecting signs of microbial components and cell damage on the outside of the cell. Now other PR RSR found embedded in the membranes of faga zones and end zones which are membranes that are brought into the cell um either through the process of endo psychosis or Figo psychosis. And so notice here we have an end to Zamora fags. Um I might say which is this membrane that results from fargo psychosis. And notice that there are PR Rs here embedded in the membrane of the faga zone and those are going to be important for detecting microbial components that have been ingested by the cell. So some PRS detect components on the outside of the cell. Some PR Rs detect components that have been ingested by the cell. And then last but not least, some P. R. R. S. Are found in the cell's cytoplasm. And so those pr R. S like this one that you see right here are going to be important for detecting microbial components and damage inside uh the cell. So some pr Rs detect microbial components outside the cell. Some detect microbial components that have been ingested by the cell. And other PRS detect microbial components that are inside of the cell. And so we'll be able to talk about these different types of P. R. R. S and exactly where they are found and what they help detect as we move forward in our course. But for now, this year concludes our brief introduction to pattern recognition receptors or PR Rs. And once again as we move forward in our course, we'll get to learn a lot more. So I'll see you all in our next video
2
concept
MAMPs & DAMPs
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in this video, we're going to introduce the two terms maps and damps. And so first we need to recall from some of our previous lesson videos that immune cells use pattern recognition receptors or PR Rs to detect different types of signs that will indicate either microbial invasion or host cell damage. Now the term ma'am, this is an abbreviation for microbe associated molecular patterns and microbe associated molecular patterns or Ma'am. This is going to represent signs of microbes. Now, signs of pathogens are referred to as pants and sew pants are going to be pathogen associated molecular patterns. And so really the terms mammoths and pants can be used interchangeably to refer to a broad group of different types of molecules that are associated directly with microbes or pathogens. And so some examples of mammoths or pants include lipo, polly, sacha ride or LPS, a component found in the outer surface membranes of gram negative bacteria, peptidoglycan, a molecule specific to bacterial cell walls, viral nucleic acids, fungal cell walls and floor Jelen, a protein component important for bacterial flu gela. And so these are all direct signs of microbes or pathogens. And so these are all examples of what could be considered maps or champs. Now damps. On the other hand, our damage associated molecular patterns and so these are not direct signs of microbes. Instead, they're more like indirect signs of microbes and pathogens but their direct signs that indicate host cell damage. And so these are molecules that actually originate from the host but they indicate host cell damage. So for example, it could be perhaps some kind of fossil lipid component of a host cell membrane or something of that nature, something that belongs to the host that indicates that the host cells have been damaged. And so if we take a look at our image down below, what you'll notice is that this is an image showing you a macrophage which is an immune system cell that has many different types of P. R. R. S. Many different types of pattern recognition receptors. And these different types of P. R. R. S. Can detect either maps or damps in different regions. And so some noticed that some of these P. R. R. S. Are found on the surface. And so these are going to be capable of detecting microbe or pathogen associated molecular patterns or maps on the outside of the cells. And so notice here we're showing you these P. R. R. S. That are positioned on the cytoplasmic membrane that are gonna be detecting signs of uh microbes outside the cell. And again notice that we have lipo, polly, sacha ride and peptidoglycan and fraudulent all being detected by these P. R. R. S. On the outside of the cell. Uh and then notice that we have other types of P. R. R. S. That are going to be embedded in the membranes of India's OEMs or fags. OEMs. And they can detect maps uh like for example viral DNA. Or viral RNA. Or bacterial DNA. Uh that have been ingested by the cell. And we have other PR. R. S. That are cytoplasmic p. R. R. S. That can detect, you know, either man or damps and damps are again damage associated molecular patterns um or just damps. And those are going to detect damage to cellular components. And so this year concludes our brief introduction to these terms maps and damps, molecular associated uh molecular microbe associated molecular patterns and damage associated molecular patterns. And so we'll be able to apply some of these concepts as we move forward in our course. So I'll see you all in our next video.
3
Problem
Problem
Which of the following are PRRs least likely to detect?
A
Glycolysis enzymes.
B
Peptidoglycan.
C
Flagellin.
D
Lipopolysaccharide.
E
Foreign nucleotide sequences.
4
concept
Toll-Like Receptors
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3m
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in this video, we're going to introduce toll like receptors or T. L. R. S. For short. And so the most well characterized type of P. R. R. Or pattern recognition receptor are the tall like receptors now toll like receptors are commonly abbreviated as T. L. R. S. And so these toll like receptors or T. L. R. S. R, membrane embedded PR Rs or membrane embedded pattern recognition receptors that are used to detect Ma'am, this um outside of the cell or mammoths that have been ingested by the sell through the process of endo psychosis or Figo psychosis. Now the T. L. R. S. Or toll like receptors once again, they can either be found in the cell membrane uh in the cell cytoplasmic membrane or they could be found embedded in the membranes of India's OEMs and faga zones which are these membrane vesicles that result from endo psychosis or Figo psychosis. Now the T. L. R. S. That are found embedded in the cell. Cytoplasmic membrane will face outward on the cell surface in order to detect uh MA'am on the outside of the cell. But the T. L. R. S. That are found in the end as OEMs or fags. OEMs are going to face inward in order to monitor what is engulfed via endo psychosis or figure acidosis. And once again these T. L. R. S are going to recognize maps such as for example microbial nucleic acids like for example, double stranded RNA, which is found in some types of viruses but is not common in the host cell at all. And so once a microbial invasion has been detected. Once a map has been detected by A. T. L. R. It can then initiate some kind of immune response like for example the release of a site a kind for example. And so if we take a look at our image down below over here on the left hand side notice that we're showing you our map of the lesson on the scanning systems of innate immunity which are going to serve to detect signs of microbes and serve someone as security cameras. And so these pattern recognition receptors or Pr. R. S are going to help detect signs of maps and damps microbe associated molecular patterns and damage associated molecular patterns and there are many different types of pattern recognition receptors. But here in this video we're focusing on the toll like receptors or the T. L. R. S. And so these toll like receptors or T. L. R. S. Again our membrane embedded pattern recognition receptors. So they are going to be found embedded in the membrane the cytoplasmic membrane and they will be facing towards the outside of the cell where they can detect signs like for example like a poly sacha ride or potato like an orphanage Ellen or they can be found embedded in the membranes of Windows OEMs or fags OEMs and they're going to be facing inwards so that they can detect what has been ingested within the Windows OEM or Fascism. And so uh this year concludes our brief lesson on these toll, like receptors or T. L. R. S. And we'll be able to learn about the other types of pattern recognition receptors as we move forward in our course. So I'll see you all in our next video.
5
Problem
Problem
Toll-like receptors (TLRs) bind molecules on pathogens. Why is this helpful to the immune response?
A
It provides a highly specific response to very small and highly unique areas on an individual pathogenic microbe, providing the most specific and selective response possible.
B
It provides a general response to broad categories of molecules/cells that should NOT be in our system, as we don't have these molecules on our own cells.
C
These secreted molecules help bind pathogens and then direct them to receptors on the immune system cells that are best capable of eliminating them from our systems. TLRs are delivery mechanisms for the immune responses.
D
TLRs are capable of directly lysing (destroying) the microbes, helping our immune responses by eliminating pathogens.
6
concept
C-Type Lectin Receptors
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2m
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in this video we're going to introduce the C. Type leptin receptors or cl ours. And so another type of P. R. R. Or pattern recognition receptor that's located on the cell surface are the C. Type leptin receptors. And so these C type leptin receptors are commonly abbreviated as C L. R. S. And so these C type leptin receptors or C l R. S. R. Again cell surface pattern recognition receptors or pr Rs that bind to carbohydrates maps on the microbial surfaces. And so some microbes have carbohydrate maps on their surfaces. And these C. Type leptin receptors are found on our own immune cells and they can bind to the carbohydrate maps that are found on these microbial surfaces. Now lecterns themselves which are found within the name C type left and receptors are proteins that bind to specific carbo hydrates. And so that's really what lecterns are. And so if we take a look at our image down below, over here on the left hand side, once again we're showing you our map of the lesson on the scanning systems of innate immunity which served to detect signs of microbes and served as somewhat like security cameras. And so here we're talking about the pattern recognition receptors, specifically the C type leptin receptors. And so once again these C type leptin receptors are going to be membrane embedded receptors on the cell surface. And what you'll notice is that these C type elected receptors. They have a green region right here that we refer to as the leptin protein. And elected protein is capable of binding to carbohydrates. In fact it will bind to carbohydrates like this one that are found on the microbial surface. And so our host cell is able to use the CLR is to bind and recognize carbohydrate maps found on microbe surfaces. And then once again the C. Type leptin receptor has bound a carbohydrate ma'am on the microbial cell surface. It can then initiate some kind of immune response. For example, perhaps the release of some kind of cytokine. And so this year concludes our brief lesson on C. Type leptin receptors or C. L. R. S. And once again we'll be able to apply some of these concepts as we move forward and learn about the other pattern recognition receptors as well as we move forward to. So see you on the next video.
7
Problem
Problem
Which of the following is not considered a MAMP (Microbe/Pathogen-Associated Molecular Pattern)?
in this video we're going to briefly discuss the nucleotide binding and a liga Marie ization domain like receptors or in other words for short. Just the nod like receptors. And so these nod like receptors are commonly abbreviated as N. L. Ours. And unlike the other two types of pattern recognition receptors that we've talked about in our previous lesson videos including the toll like receptors and C type leptin receptors which are membrane bound receptors. The nod like receptor is not membrane bound. Instead the nod like receptor or N. L. R. Is a cytoplasmic receptor meaning that it is not embedded in the membrane and it is dissolved within the cytoplasm. And so this nod like receptor or N. L. R. Is a cytoplasmic receptor protein or a cytoplasmic P R R a cytoplasmic pattern recognition receptor that is going to detect intracellular maps or damps. So these not like receptors which are cytoplasmic P. R. R. S. They play an important role in the immune response of macrophages and dendritic cells. And when an Nl R detects a map uh they can combine with other cytoplasmic proteins to form what is known as an influence zone. And this influence zone can be defined as a structure that is capable of activating pro inflammatory cytokine production leading to inflammation. And so if we take a look at our image down below, once again on the left hand side we have our map of the lesson on the scanning systems and we're focusing specifically on the nod like receptors here and notice that these not like receptors can be found in macrophages and dendritic cells and notice that they are cytoplasmic pattern recognition receptors. Okay so they're found dissolved in the cytoplasm. They are not embedded in membranes. And so when these nod like receptors or N. L. R. S. Bind to maps and damps inside the cell. So here's an NlRB binding to some kind of man or damp. It can lead to the formation of what is known as an influence zone. And the infamous zone will form which will activate cytokine production. And so here we have the infamous um formation and the formation of the infamous um will trigger the release of cytokines And those cytokines can trigger inflammation and inflammation is an entire response that can help to eliminate the microbes that are causing problems. And so what you can see here is that uh these not like receptors are again cytoplasmic P. R. R. S. That detect signs of intracellular maps and damps and can lead to some kind of response that can ultimately help to eliminate those microbes or pathogens. And so this here concludes our brief lesson on the nod like receptors or N. L. R. S. And we'll be able to get some practice applying some of these concepts and then we'll talk about the final type of pattern recognition receptor the rig like receptors. So I'll see you all in our next lesson video
9
Problem
Problem
Why are NOD-like receptors (NLRs) important for macrophage cells?
A
Macrophages commonly ingest infectious material and use NLRs to detect intracellular MAMPs.
B
Macrophages are unstable and commonly have intracellular damage and use NLRs to detect DAMPs.
C
Macrophages use NLRs to detect MAMPs which triggers the formation of RIG-like receptors.
D
Macrophages are the only cells able to detect viral infection and use NLRs to detect viral RNA.
10
concept
Retinoic acid Inducible Gene (RIG)-Like Receptors
Video duration:
3m
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in this video we're going to briefly discuss retinoic acid induced double gene like receptors or for short rig like receptors. Now these rig like receptors are a second type of cytoplasmic pR are in addition to the nod like receptors that we talked about in some of our previous lesson videos. And so once again these rigs like receptors are cytoplasmic p R. R. S. That are capable of detecting cytoplasmic maps. Yeah or cytoplasmic microbe associated molecular patterns. Now specifically these rig like receptors are cytoplasmic proteins or cytoplasmic P. R. R. S. That detect viral RNA. And uh the these rig like receptors that are capable of detecting viral RNA in the cytoplasm are found in most types of host cells. Now the rig like receptors are capable of distinguishing between host cell RNA and viral RNA by two features that we have listed down below. The first feature is that viral RNA can be double stranded and double stranded. RNA is quite unique and really only found in some types of viruses and host RNA is not double stranded. So that makes it easy to distinguish the host cell's RNA from viral RNA. Now a second important feature that helps distinguish host RNA from viral RNA is that host cell RNA is going to have a five prime cap as well as a poly a tail, A three Prime Poly A Tail. However, viral RNA does not have a five prime cap or a poly a tail. And so that is another way to distinguish between host cell RNA and viral RNA. And so if we take a look at our image down below over here on the left hand side notice we have our map of the lesson on the scanning systems of innate immunity which served to detect signs of microbes and host cell damage. And they serve somewhat as these security cameras. And so here in this video we're focusing specifically on pattern recognition receptors, specifically these rig like receptors. And so these rig like receptors again are capable of detecting viral RNA. And so when a virus infects a cell. So here we have an infecting virus uh it will uncoated and release its genetic material and that viral genetic material can be transcribed through the process of transcription to make viral RNA either viral single stranded RNA or viral double stranded RNA. It. And so regardless if it's viral single stranded RNA or viral double stranded RNA. The rig like receptors which are down below right here are capable of distinguishing uh the host cell's RNA, which noticed the host cell's RNA is over here, it is single stranded and it has a five prime cap and a poly a tail from the viral RNA. And so that's because again the viral RNA is uh not going to have the five prime cap or poly a tail and also viral RNA can be double stranded. And so these rigs like receptors will detect these viral RNA molecules and upon detecting the viral RNA molecules it could initiate some kind of immune response. Like for example the release of a site a kind perhaps an interfere on, for example, which we'll get to talk about the interferon response in more detail later in our course. But for now this year concludes our brief lesson on these rig like receptors and we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.
11
Problem
Problem
What defining features of viral RNA allows the RIG-like receptors to distinguish infecting viral RNA from the host cell's RNA?
A
Viral RNA has a 5' cap while host cell RNA does not.
B
Viral RNA has a poly-A tail while host cell RNA does not.
C
Viral RNA can be double stranded while host cell RNA is single stranded.
D
Viral RNA has a circular formation while host cell RNA is linear.
E
None of the above.
12
Problem
Problem
In addition to peptidoglycan, which molecule(s) unique to bacteria would PRRs recognize?
A
Lipopolysaccharide (LPS).
B
Fungal cell walls.
C
Flagellin proteins.
D
Tubulin proteins found in cilia.
E
A and C.
F
B and D.
G
All of the answers would be recognized by PRRs.
13
Problem
Problem
Toll-like receptors are receptor proteins on ___________.
A
Granulocytes that destroy parasitic helminths.
B
Phagocytes that recognize foreign or microbe-associated molecules.
C
Viruses entering the body which stimulate the immune system.
D
Mucus producing cells that trigger mucus production when they bind with an allergen.
14
Problem
Problem
Which type of pattern recognition receptor when bound to MAMPs triggers the formation of the inflammasome?
