coIP

coIP is an abbreviation most commonly used for co-immunoprecipitation, a biochemical method used to study protein–protein interactions. In this context, the “co-” prefix indicates that a target protein is isolated together with proteins that are bound to it, by using an antibody against the protein of interest to pull down the complex from a cell lysate.

Procedure typically involves extracting proteins under mild conditions, incubating the extract with a specific antibody, and capturing the antibody–antigen complexes with protein A/G–conjugated beads. After washing to reduce non-specific binding, the precipitated proteins are eluted and analyzed by methods such as Western blotting or mass spectrometry to identify potential interaction partners. The technique is widely used to map interaction networks and to validate suspected protein complexes identified by other approaches.

Interpretation of coIP results requires careful controls and awareness of limitations. While it can reveal proteins that associate with the target in a cellular context, it does not always distinguish direct physical interactions from indirect associations within larger complexes. Non-specific binding can occur, so negative controls (such as non-specific antibodies or knockout/knockdown samples) and quantitative comparisons are important. Crosslinking can be used to stabilize transient interactions, but it can also introduce artifacts.

In practice, coIP is often spelled without a hyphen as coIP or CoIP in some texts, and may appear in different cases across publications. Outside this specific laboratory context, the acronym coIP has no universal meaning. When encountered, the intended meaning should be confirmed from the source.