Question

Which of the following technique(s) is used for protein-protein interaction studies?

• A. Co-immunoprecipitation
• B. Yeast one hybrid system
• C. Western blotting
• D. 2D gel electrophoresis

Hint:

Think of Co-IP like a "buddy system." If you grab one friend (the bait) with a hook (antibody), you also end up pulling out anyone holding their hand (the prey).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Determining how proteins interact is fundamental to understanding cellular processes, signaling pathways, and structural assemblies. Various biochemical and genetic methods are employed to detect physical interactions between proteins.

Step 2: Detailed Explanation:
Co-immunoprecipitation (Co-IP) is a standard biochemical technique for protein-protein interaction studies. It works by using an antibody specific to a known "bait" protein. When this antibody is used to precipitate the bait protein from a cell lysate, any proteins physically interacting with the bait (the "prey") will also be pulled down (precipitated) as part of the complex. The presence of interacting proteins is then usually detected by Western blotting.
Other listed techniques target different levels of molecular biology:
- Yeast one-hybrid system is designed to detect protein-DNA interactions (e.g., identifying transcription factors that bind to a specific promoter sequence). Note that Yeast two-hybrid is used for protein-protein interactions.
- Western blotting is a method to detect a single protein in a sample using antibodies, often used as a detection tool after Co-IP, but not an interaction discovery tool on its own.
- 2D gel electrophoresis separates proteins based on their isoelectric point and molecular weight, primarily used in proteomics for protein profiling, not for detecting binary interactions.

Step 3: Final Answer:
Co-immunoprecipitation is the gold-standard technique among the options for identifying physical protein-protein interactions.