Biomedical Engineering Reference
In-Depth Information
Chapter 2
Regulation of Actin Cytoskeleton Dynamics
in Migrating Cells
This chapter gives an overview of the biochemical and biomechanical factors that
are involved in the regulation of actin cytoskeleton, and explores how coupling
between these factors contribute to synchronized cell movement. Specifi cally, the
generation of mechanical forces by polymerization and actin-myosin II interactions
is reviewed, and the infl uence of such forces on actin structure dynamics during cell
movement is discussed. Moreover, the contribution of actomyosin contractility to
traction force generation is examined and correlated with actin network dynamics
during cell movement.
2.1
Introduction
The complex processes involved in cell migration; polymerization, adhesion, and
retraction, are mediated by highly orchestrated structure-function interactions that
occur within the actin cytoskeletal structure in migrating cells. Thus, clarifying how
migrating cells regulate the global dynamics of their cytoskeletal components,
which result from rather localized protein-protein interactions, is fundamental to
understanding the mechanisms of cell motility.
As illustrated in Fig.
2.1
, cell migration is mediated by actin network dynamics
involving polymerization and depolymerization; molecular events orchestrated by
biochemical factors such as Arp2/3 and cofi lin at the level of a single fi lament.
Biochemical regulators of polymerization and depolymerization are in turn coupled
with mechanical regulators, which are mainly contractile forces generated by
actomyosin interactions within the cytoskeleton and at the focal adhesions. Thus, in
a nutshell, coupling interactions involving biochemical and mechanical factors
(mechanochemical coupling) lead to the coordinated regulation of cell migration
processes such as protrusion, adhesion, and retraction.
This chapter focuses on the mechanical aspects of actin network dynamics and
its regulatory role in cell migration. Important mechanical forces involved in cell
