Chapter 29
Control of Cell Migration Using Optogenetics
Leo Valon and Simon de Beco
Abstract
Optogenetics uses light to manipulate protein localization or activity from subcellular to supra-cellular level
with unprecedented spatiotemporal resolution. We used it to control the activity of the Cdc42 Rho
GTPase, a major regulator of actin polymerization and cell polarity. In this chapter, we describe how to
trigger and guide cell migration using optogenetics as a way to mimic EMT in an artificial yet highly
controllable fashion.
Key words Optogenetics, Rho GTPase, Cdc42, Polarity, Migration, Lamellipodium, Microscopy
1 Introduction
Epithelial-to-Mesenchymal Transition (EMT) involves several phenotypic changes including loss of apicobasal polarity and cell–cell
adhesion while cell migration and invasiveness are increased. Rho
GTPases play a major role in these processes, and it is no surprise
that they have been shown to be involved in Contact Inhibition of
Locomotion (CIL) and EMT [1, 2]. Schematically, active Rac1 and
Cdc42 are found at the cellular front where they drive actin polymerization resulting in the formation of lamellipodia and filopodia
[3, 4]. Conversely, RhoA is mostly known to control myosin II
activity resulting in the formation of stress fibers and retraction of
the back of motile cells during mesenchymal migration
[5]. Controlling Rho GTPases activity is thus of particular importance to study the mechanisms of cell migration during EMT.
Several methods have been developed in order to control Rho
GTPases activity at the cellular and subcellular levels. The use of
genetic mutations and drugs offers convenient methods but lacks
the spatial and temporal precision needed to match the dynamics of
these proteins as observed ex vivo and in vivo (typically, a few
micrometers and tens of seconds, [6]). Microfluidics make it possible to create controlled gradients of chemoattractants that result in
Kyra Campbell and Eric Theveneau (eds.), The Epithelial-to Mesenchymal Transition: Methods and Protocols,
Methods in Molecular Biology, vol. 2179, https://doi.org/10.1007/978-1-0716-0779-4_29,
© Springer Science+Business Media, LLC, part of Springer Nature 2021
415
Control of Cell Migration Using Optogenetics
Leo Valon and Simon de Beco
Abstract
Optogenetics uses light to manipulate protein localization or activity from subcellular to supra-cellular level
with unprecedented spatiotemporal resolution. We used it to control the activity of the Cdc42 Rho
GTPase, a major regulator of actin polymerization and cell polarity. In this chapter, we describe how to
trigger and guide cell migration using optogenetics as a way to mimic EMT in an artificial yet highly
controllable fashion.
Key words Optogenetics, Rho GTPase, Cdc42, Polarity, Migration, Lamellipodium, Microscopy
1 Introduction
Epithelial-to-Mesenchymal Transition (EMT) involves several phenotypic changes including loss of apicobasal polarity and cell–cell
adhesion while cell migration and invasiveness are increased. Rho
GTPases play a major role in these processes, and it is no surprise
that they have been shown to be involved in Contact Inhibition of
Locomotion (CIL) and EMT [1, 2]. Schematically, active Rac1 and
Cdc42 are found at the cellular front where they drive actin polymerization resulting in the formation of lamellipodia and filopodia
[3, 4]. Conversely, RhoA is mostly known to control myosin II
activity resulting in the formation of stress fibers and retraction of
the back of motile cells during mesenchymal migration
[5]. Controlling Rho GTPases activity is thus of particular importance to study the mechanisms of cell migration during EMT.
Several methods have been developed in order to control Rho
GTPases activity at the cellular and subcellular levels. The use of
genetic mutations and drugs offers convenient methods but lacks
the spatial and temporal precision needed to match the dynamics of
these proteins as observed ex vivo and in vivo (typically, a few
micrometers and tens of seconds, [6]). Microfluidics make it possible to create controlled gradients of chemoattractants that result in
Kyra Campbell and Eric Theveneau (eds.), The Epithelial-to Mesenchymal Transition: Methods and Protocols,
Methods in Molecular Biology, vol. 2179, https://doi.org/10.1007/978-1-0716-0779-4_29,
© Springer Science+Business Media, LLC, part of Springer Nature 2021
415