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Updated: Jun 18, 2026
Flow Cytometric Analysis of Bimolecular Fluorescence Complementation: A High Throughput Quantitative Method to Study Protein-protein Interaction
Published on: August 15, 2013
Visualization of multiprotein complexes by flow cytometry
1Mayo Clinic College of Medicine, Rochester, Minnesota.
Insights
This study introduces a novel flow cytometry method to analyze protein-protein interactions in their native state. The technique, called immunoprecipitation-flow cytometry (IP-FCM), offers a sensitive way to study these crucial cellular processes.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Protein-protein interactions are fundamental to cellular functions.
- Existing methods for analyzing these interactions can be complex or require sample manipulation.
Purpose of the Study:
- To develop a sensitive and robust method for analyzing native protein-protein interactions.
- To enable the quantification of protein complex formation without genetic engineering.
Main Methods:
- Developed a flow cytometry-based assay (IP-FCM) using antibody-coupled beads for immunoprecipitation.
- Analyzed protein complexes in cell lysates by probing with fluorochrome-conjugated antibodies.
- Utilized quantitative flow cytometry to estimate co-associated molecules.
Main Results:
- The IP-FCM method allows for sensitive detection of protein-protein interactions in a native state.
- The technique is compatible with flow cytometry and requires minimal sample input.
- Quantitative analysis enables semiquantitative estimation of co-associated molecules.
Conclusions:
- IP-FCM is a robust technique for assessing native protein-protein interactions.
- This method provides a valuable tool for studying cellular processes involving protein complexes.
- The approach circumvents the need for genetic manipulation or large sample volumes.
Abstract:
Multiprotein complexes and other protein-protein interactions play important roles in virtually all cellular processes. Analysis of coimmunoprecipitation of protein complexes by flow cytometry (IP-FCM, or "the fly-p" method) provides a sensitive means to measure these interactions in the native/nondenatured state. First, immunoprecipitating antibodies are covalently coupled to polystyrene latex beads whose low autofluorescence is compatible with flow cytometry. These antibody-coupled beads are used to immunoprecipitate a specific protein (primary analyte) present in cell lysates. Finally, the protein complexes associated with the beads are probed with fluorochrome-conjugated antibodies specific for interaction partners, or secondary analytes, that may be associated with the primary analyte. The use of quantitative flow cytometric methodology can allow the semiquantitative fluorescence data generated to be converted into estimated numbers of co-associated molecules on the beads. The method represents a robust technique to assess native protein-protein interactions without requiring genetic engineering or large sample sizes.
