Quantification of the Interactions Between BCL-2 Proteins by Fluorescence Correlation Spectroscopy

  • Fabronia Murad
  • Ana J. Garcia-SaezEmail author
Part of the Methods in Molecular Biology book series (MIMB, volume 1877)


The proteins of the Bcl-2 family regulate apoptosis by forming a complex interaction network whose output determines whether mitochondrial outer membrane permeabilization is executed. Quantification of complex formation between Bcl-2 proteins in solution and in membranes is therefore key to understand how the hierarchy of interactions controls cell death induction. Fluorescence correlation spectroscopy (FCS) is a noninvasive, nondestructive method to investigate the mobility and the association of fluorescently labeled biomolecules that has provided useful insight into the binding affinity of the Bcl-2 interactome. FCS is based on the detection of fluorescence fluctuations caused by the diffusion of individual molecules through a very tiny observation volume of the detection system. Scanning FCS (SFCS) solves some of the practical challenges of acquiring FCS in membranes and expands the application scope of the method. In this chapter, we explain the principle of FCS and describe protocols how it can be used to quantify interactions between Bcl-2 proteins in solution and in model membrane systems.

Key words

Fluorescence correlation spectroscopy FCS FCCS Scanning FCCS Bcl-2 Bcl-xL Bax cBid 


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Interfaculty Institute of BiochemistryUniversity of TübingenTübingenGermany

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