Yeast Two Hybrid Screening - Cancer Science

What is Yeast Two Hybrid Screening?

The Yeast Two Hybrid (Y2H) screening is a molecular biology technique used to detect protein-protein interactions. Developed in the late 1980s, this method employs the yeast Saccharomyces cerevisiae as a living host to explore the interactions between two proteins, termed the "bait" and the "prey". When these proteins interact, they enable the expression of a reporter gene, providing a straightforward readout of the interaction.

How Does It Work?

In Y2H screening, the bait protein is fused to a DNA-binding domain, while the prey protein is fused to an activation domain. If the bait and prey proteins interact within the yeast cell, the activation domain is brought into proximity with the DNA-binding domain, which drives the transcription of a reporter gene. This gene typically encodes for a protein that can be easily detected, such as beta-galactosidase or an antibiotic resistance marker.

Why is Y2H Screening Important in Cancer Research?

Cancer is fundamentally a disease of dysregulated cellular processes, often driven by aberrant protein-protein interactions. Identifying these interactions can reveal novel therapeutic targets and provide insights into mechanisms of drug resistance or tumor progression. Y2H screening allows researchers to map interaction networks and identify critical nodes that could be targeted for cancer therapy.

Applications of Y2H in Cancer Research

Y2H screening has been used to identify interactions involving oncogenes, tumor suppressors, and proteins involved in signal transduction pathways. For instance, the identification of interactions involving the tumor suppressor p53 has been pivotal in understanding its role in cancer. Similarly, Y2H has been used to explore the network of interactions involving the human epidermal growth factor receptor 2 (HER2), which is overexpressed in certain types of breast cancer.

Advantages and Limitations

The primary advantage of Y2H screening is its ability to identify interactions in a living cell, providing a more physiologically relevant context compared to in vitro methods. Additionally, it can be scaled to screen large libraries of potential prey proteins, making it a powerful tool for high-throughput screening.
However, Y2H screening has limitations. It can produce false positives and false negatives due to non-specific interactions or the inability of certain proteins to functionally express in yeast. Furthermore, interactions detected in yeast may not always reflect those in human cells, necessitating follow-up validation in mammalian systems.

Future Directions

Advancements in next-generation sequencing and computational biology are enhancing the power of Y2H screening. Integrating Y2H data with other omics approaches, such as proteomics and transcriptomics, can provide a more comprehensive view of the molecular networks driving cancer. Additionally, innovations such as dual-bait systems and the use of humanized yeast strains are expanding the applicability of Y2H screening in cancer research.