UNIT 9.36 In Situ Proximity Ligation Assay for Microscopy and Flow Cytometry

  1. Karl-Johan Leuchowius,
  2. Irene Weibrecht,
  3. Ola Söderberg

Published Online: 1 APR 2011

DOI: 10.1002/0471142956.cy0936s56

Current Protocols in Cytometry

Current Protocols in Cytometry

How to Cite

Leuchowius, K.-J., Weibrecht, I. and Söderberg, O. 2011. In Situ Proximity Ligation Assay for Microscopy and Flow Cytometry. Current Protocols in Cytometry. 56:9.36:9.36.1–9.36.15.

Author Information

  1. Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden

Publication History

  1. Published Online: 1 APR 2011
  2. Published Print: APR 2011


The ability to study proteins and protein interactions inside cells and tissues is important for elucidating how cells function in health and disease. The in situ proximity ligation assay (in situ PLA) presented here can be used to visualize proteins, protein-protein interactions, and post-translational modifications in cells and tissues. The method is based upon the use of antibodies that target the proteins involved in an interaction; hence, the method has the advantage that it can be used in clinical specimens, providing localized, quantifiable single molecule detection in single cells. This unit describes how in situ PLA can be used with fluorescence microscopy and flow cytometry to study proteins (obtaining high sensitivity and specificity of detection) and protein interactions. It also includes information on expected results and information on how to troubleshoot the assay. Curr. Protoc. Cytom. 56:9.36.1-9.36.15. © 2011 by John Wiley & Sons, Inc.


  • in situ;
  • proximity ligation;
  • protein interactions;
  • post-translational modifications