A Single-Cell Biochemistry Approach Reveals PAR Complex Dynamics during Cell Polarization

Publication date: 21 August 2017
Source:Developmental Cell, Volume 42, Issue 4
Author(s): Daniel J. Dickinson, Francoise Schwager, Lionel Pintard, Monica Gotta, Bob Goldstein
Regulated protein-protein interactions are critical for cell signaling, differentiation, and development. For the study of dynamic regulation of protein interactions in vivo, there is a need for techniques that can yield time-resolved information and probe multiple protein binding partners simultaneously, using small amounts of starting material. Here we describe a single-cell protein interaction assay. Single-cell lysates are generated at defined time points and analyzed using single-molecule pull-down, yielding information about dynamic protein complex regulation in vivo. We established the utility of this approach by studying PAR polarity proteins, which mediate polarization of many animal cell types. We uncovered striking regulation of PAR complex composition and stoichiometry during Caenorhabditis elegans zygote polarization, which takes place in less than 20 min. PAR complex dynamics are linked to the cell cycle by Polo-like kinase 1 and govern the movement of PAR proteins to establish polarity. Our results demonstrate an approach to study dynamic biochemical events in vivo.

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Teaser

Single-cell analysis is becoming increasingly important for cell biology. Dickinson et al. describe a single-cell assay for protein interactions, using microfluidic lysis and single-molecule pull-down. They apply this approach to show that PAR complex assembly is dynamic and is linked to the cell cycle during cell polarization in C. elegans.


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