ABC Transporters - Video Tutorials & Practice Problems
On a tight schedule?
Get a 10 bullets summary of the topic
1
concept
ABC Transporters
Video duration:
35s
Play a video:
Video transcript
Hey guys. So here we're going to quickly revisit our map of the lesson on membrane transport. And we know that we're currently exploring the active transport branch, more specifically the primary active transport branch. And we've talked about the 5 types of ATPases including 2 very specific types of p type ATPases, which are the sodium potassium pump and the circa pump. And so now in our next video, we're going to talk even more details about the ABC transporters, one of the 5 types of ATPases. And so I'll see you guys in that video.
2
concept
ABC Transporters
Video duration:
6m
Play a video:
Video transcript
In this video, we're going to talk a little bit more details about one of the 5 types of ATPases, the ABC transporters. Transporters. And so really the main takeaway of this video is that ABC transporters can provide multi drug resistance. And so the ABC part of ABC Transporters stands for ATP binding cassette, ABC. And so the ATP binding cassette transporters or ABC transporters are really just integral membrane proteins proteins with at least 1 ABC structural motif. And so recall that motifs are just a combination or a pattern of secondary structures and proteins. And again, because ABC transporters are a type of ATPase, they are a form of primary active transport. So it's no surprise that these guys pump substances across the membrane against their concentration gradient, from areas of low concentration to areas of high concentration. Now another defining features of these a b c transporters are the structural elements that they contain. And so all a b c transporters actually share 2 common structural elements. The first are that they all contain 2 transmembrane domains or 2 TMDs for short. And of course as their name implies these are transmembrane, so they span the membrane and of course that's going to help create this pore that allows them, a pore through the membrane that allows them to transport molecules across the membrane. Now the second common structural element that all a b c transporters have is that they all have 2 cytosolic Nucleotide Binding Domains or 2 NBDs for short. And so these nucleotide binding domains will bind and hydrolyze ATP, which recall ATP is a nucleotide. And so within these nucleotide binding domains, that's where you could find the ATP binding cassette, this specific structural motif. So if we take a look at our image down below, notice we're showing you an a b c transporter. And embedded within this plasma membrane right here, you can see the structure of this a b c transporter. Notice that, spanning the membrane there are these 2 transmembrane domains here that we have highlighted here in pink, and then on the cytosolic side of the cell, we have these 2 nucleotide binding domains or these 2 NBDs right here. And of course the nucleotide binding domains can bind and hydrolyze ATP as we see here. And that's exactly what we mentioned and described up above, the 2 TMDs and the 2 NBDs. Now it's also important to note that some ABC Transporters are called multidrug resistance or MDR transporters for short, and that's because these will particularly be responsible for resistance to multiple drugs. And so in bacteria, MDR transporters will actually confer antibiotic resistance. And in humans, there's a protein called p glycoprotein or PGP, which is an MDR transporter that removes anticancer drugs from tumor cells. And so, essentially what we're seeing here is that MDRs are of great importance to humans because MDRs can confer antibiotic resistance in bacteria, which can create a problem, a health problem for humans. And so that's why a lot of research goes into MDR transporters, to see how we can work around the MDR transporters that are providing antibiotic resistance to some bacteria that might be causing humans health problems. And also in humans, it's also, an area of high research as well because, again, p glycoprotein here can remove anti cancer drugs in tumor cells. And so, again that can be very problematic and it's an area that is very highly researched. And so what you'll notice here is we have this tiny little stethoscope over here on the left, and this is a symbol that we're going to use moving forward in our course to represent something that you might wanna pay a little bit more, you know, pay close attention to it, because if you're going on into medical school or some kind of other medical profession like maybe pharmacy or something like that, wherever we have this symbol, this is a place where you might wanna hone in and keep this idea in mind in case you encounter this idea again. Because if you're if you are going on into medical school or again some other kind of medical profession, this is an idea here that you'll probably revisit. And so if we take a look at our image down below, notice that we're showing you these red lines right here, that are taking toxins and drugs and pumping them to the outside of the cell. And a, b, c transporters or MDR transporters can take toxins or drugs that are embedded within the plasma membrane and remove them, pump them to the outside of the cell, and they can also take drugs that are in the cytoplasm and toxins that are in the cytoplasm and remove them and pump them to the outside of the cell against their concentration gradient while utilizing and hydrolyzing ATP. And so this here concludes our lesson on ABC Transporters, and as we move forward in our course we'll be able to get some practice applying these concepts. So I'll see you guys in our next video.
3
Problem
Problem
ABC transporters are a part of a superfamily of transporters that have two nucleotide binding domains that bind __________, which is necessary for primary active transport.
A
ADP.
B
Phosphate.
C
ATP.
D
GTP.
E
AMP.
4
Problem
Problem
What side of a membrane has a higher concentration of the toxin Limbricide after ABC transporter activity?
A
Inside the cell.
B
outside the cell.
5
Problem
Problem
Which of the following statements is TRUE for BOTH P-type ATPases and ABC transporters?
A
They each have two ATP-binding protein domains.
B
They both contain a phosphorylated Asp residue.
C
They both are examples of multi-drug resistant proteins that pump toxins out of the cell.
D
They are both dependent on the presence of ATP.
E
They both require ATP binding before substrate binding and transport.