Co-immunoprecipitation (Co-IP) Assay

The Co-IP assay is a powerful technique that is widely used for the discovery and detection of protein-protein interactions. The principle of this technology is to utilize the antigen-antibody interaction to pull-down putative interactive partners of the target protein. Specifically, the antibody of the target protein is immobilized in affinity resins, which are then exposed to a designed protein mixture, or a cellular extraction. Therefore, proteins or protein complexes that have strong interactions with the target protein will be co-precipitated; and the identities and amounts of these interactive proteins can be revealed by multiple analytical approaches.

The general procedures for a standard Co-IP assay are as follows (Figure 1)

1. Preparation of protein mixture, cell lysate or tissue extractions
2. Incubation of protein mixture, cell lysate or tissue extractions with antibody-bound affinity beads
3. Clearance of unbound proteins with multiple washing steps
4. Detection of interactive proteins via SDS-PAGE, western blot or mass spectrometry (MS) analysis

Figure 1. The workflow of a standard Co-IP assay.

Comparing to other protein interaction methods, the Co-IP assay has the advantages of

• The prey proteins are pulled-down at their native status, which reduces the chance of artificial interaction.
• Allows pull-down of an entire protein complex and is very informative for the characterizations of proteins and their functional pathways.
• High compatibility with a variety of sample preparation and protein identification methods.
• Simple and straightforward to perform.

Lifeasible, as a predominant plant biotechnology company, has many years of experience in the study of plant molecular biology, plant biochemistry and plant cell biology. We provide superior services for Co-IP assay within the plant system. Our optimized protocols for plant protein extraction, expression and purification ensure the acquisition of bait and prey proteins with high qualities. Moreover, we provide both traditional and advanced detection approaches for the characterization of potential interactive partners.

Noticeably, to save you time and money, we also offer featured one-stop service, which covers every step of your project, including

• Experimental design
• Gene synthesis
• Protein expression and purification
• Antibody raising and immobilization
• Cell lysate preparation
• Co-IP assay performance
• Data analysis and report and consulting