Introduction to Actin-Based Cell Migration - Innovative Approaches to Cell Biomechanics - page 1

Chapter 1
Introduction to Actin-Based Cell Migration

To prepare the ground for subsequent detailed treatment of cell migration processes,
this chapter outlines the most basic aspects of cell migration, beginning with
migration steps and the structural components involved in cell migration. With
focus on the actin cytoskeleton that drives cell migration, we briefl y review the
main components of the cytoskeleton together with their roles. In addition, we look
at the structural organization of actin cytoskeleton in migrating cells, using fi sh
keratocytes as models, and discuss how fl exible actin fi laments are able to generate
forces that drive cell movement. Overall, the chapter introduces key elements of cell
migration that we consider essential to comprehend other chapters.

1.1 Introduction

Cells that form the human body are not static but move from one point to another,
usually in response to specifi c biochemical and mechanical stimuli in their local
environment. This phenomenon is called cell migration and it is essential to many
vital physiological processes including, embryo development, wound healing and
cancer metastasis. For instance, during embryo development, cells divide and
migrate to appropriate new sites where they form new tissues and organs. In the case
of wound healing, fi broblasts migrate to a wounded site where they assist in the
healing process. Still, during metastasis, cancer cells migrate from primary sites
intravasate into the blood stream and extravasate to colonize new sites.
Different cells express different modes of locomotion according to their
functionality and the nature of the surrounding physical environment (more details
are in Chaps. 8 , 9 , and 10 ) . Intriguingly, however, overall migration occurs through
related and conserved cellular and molecular mechanisms, and in most cells, it
involves the actin cytoskeleton structure (see Sect. 1.3 ) (Rafelski and Theriot 2004 ).
Thus, although keratocytes, amoeba, leucocytes, neutrophils and neuronal growth
cones (Steketee et al. 2001 ) exhibit distinctively different migration behavior, they