Tracking Protein Movement - Online Tutor, Practice Problems & Exam Prep

Tracking protein movement within cells is crucial for understanding cellular functions. Techniques such as in situ hybridization utilize fluorescent probes to visualize RNA or DNA locations. Reporter genes, like green fluorescent protein (GFP), can be fused to proteins, allowing their movement to be tracked via fluorescence. Additionally, antibodies labeled with fluorescent tags can target specific proteins, revealing their locations in the cell. These methods are essential for studying protein dynamics and cellular processes.

Tracking Proteins

Hi. In this video, I'm going to be talking to you about tracking protein movement. So you can imagine that if a scientist is studying a protein, it's going to be super important to identify where its location is in a cell. So there are a few different ways you can do this. I'm not going to mention all of them, just going to highlight a couple of important ones.

First thing I want to talk about is In situ Hybridization. And this will identify where an RNA or DNA is in a cell. So what you do is you take cells, you fix them to a microscope slide, and then you incubate them with complementary probes that have some type of fluorescence on them. So, wherever that DNA or RNA is, that probe's going to bind it because it's complementary, and then it's going to have fluorescence attached to it. And so then you can just visualize and say, where's the fluorescence? And that's going to answer where that nucleotide is. So it's an important one.

Second one is the use of reporter genes. So reporter genes are genes that can be fused to other genes, so that then when you create a protein, you now have your reporter protein and your gene of interest. This attachment allows you to look at a protein's location or movement in a cell. A really important reporter gene is green fluorescent protein, or GFP. GFP has a green fluorescence like its name suggests. So if you fuse GFP to a protein, now you have your protein and GFP, then GFP is going to be attached to that protein, and it's going to be glowing green. So anywhere that protein is, you are going to have a glowing green signal, and that allows you to see where your protein is.

But also, you can use antibodies. So antibodies target specific antigens, but you can make antibodies against specific proteins or specific molecules, or specific organelles, and then have them also labeled with fluorescence. So that wherever that protein is in a cell, then that antibody will bind it and emit fluorescence, and then you can see where it is. This is an example of using antibodies. We have three antibodies here: green, red, and blue. They're all detecting different things, and you can see where these proteins are located in the cell, based on where the color is present in the cell.

So with that, let's now move on.

Here’s what students ask on this topic:

What is in situ hybridization and how is it used to track protein movement?

In situ hybridization is a technique used to identify the location of RNA or DNA within a cell. To perform this method, cells are fixed onto a microscope slide and incubated with complementary probes that are tagged with fluorescent markers. These probes bind to their target RNA or DNA sequences, and the fluorescence allows scientists to visualize the specific locations of these nucleotides within the cell. While in situ hybridization primarily tracks RNA or DNA, it indirectly helps in understanding protein movement by identifying where the genetic instructions for those proteins are located.

How do reporter genes like GFP help in tracking protein movement?

Reporter genes, such as Green Fluorescent Protein (GFP), are used to track protein movement by fusing them to the gene of interest. When the protein is expressed, it is tagged with GFP, which fluoresces green under specific lighting conditions. This fluorescence allows researchers to visualize the location and movement of the protein within the cell. By observing the green glow, scientists can determine where the protein is at any given time, providing valuable insights into its function and dynamics within the cellular environment.

What role do antibodies play in tracking protein movement?

Antibodies are crucial for tracking protein movement because they can be designed to specifically bind to target proteins. These antibodies are often labeled with fluorescent tags. When introduced to a cell, the fluorescently labeled antibodies bind to their target proteins, allowing researchers to visualize the proteins' locations and movements. Different fluorescent colors can be used to track multiple proteins simultaneously, providing a detailed map of protein distribution and dynamics within the cell.

What are the advantages of using fluorescent tags in protein tracking?

Fluorescent tags offer several advantages in protein tracking. They provide high sensitivity and specificity, allowing for the precise localization of proteins within cells. Fluorescent tags enable real-time visualization of protein dynamics, which is essential for understanding cellular processes. Additionally, multiple proteins can be tracked simultaneously using different fluorescent colors, facilitating comprehensive studies of protein interactions and functions. These tags are also non-invasive, preserving cell viability and function during observation.

Can you explain the process of using complementary probes in in situ hybridization?

In in situ hybridization, complementary probes are used to detect specific RNA or DNA sequences within cells. The process begins by fixing cells onto a microscope slide to preserve their structure. Next, complementary probes tagged with fluorescent markers are introduced. These probes bind to their target RNA or DNA sequences due to base-pair complementarity. The bound probes emit fluorescence, which can be visualized under a microscope. This fluorescence indicates the location of the target nucleotides, providing insights into gene expression and cellular function.