Biomedical Engineering Reference
In-Depth Information
Abstract
Planar cell polarity is a fundamental concept to understanding the coordination of cell
movements in the plane of a tissue. Since the planar cell polarity pathway was discov-
ered in mesenchymal tissues involving cell interaction during vertebrate gastrulation,
there is an emerging evidence that a variety of mesenchymal and epithelial cells utilize
this genetic pathway to mediate the coordination of cells in directed movements. In this
review, we focus on how the planar cell polarity pathway is mediated by migrating cells
to communicate with one another in different developmental processes.
1. INTRODUCTION
A variety of modes of collective cell migration shape the body axis in
animal development in that both epithelial and mesenchymal cells have the
ability to coordinate morphogenetic movements but achieve in different
ways (reviewed in
Friedl & Gilmour, 2009
). During amphibian and teleost
gastrulation, polarized mesenchymal cells undergo directional cell intercala-
tions in a coordinated fashion, a morphogenetic process called convergent
extension (CE), contributing to the elongation of the presumptive noto-
chord (reviewed in
Keller, 2002
). Another mesenchymal cell population,
called prechordal plate progenitors, utilizes to direct the cells as a coherent
cluster in a mode different to notochord progenitors. In contrast, simple
epithelial cells of the anterior visceral endoderm (AVE) in mice undergo
directed movement as a cluster but use different strategies that involve
coordinated cell rearrangement. Despite the fact that the regulation of both
cell polarity and cell adhesion is fundamental to the orientation and align-
ment of the cells during tissue elongation in all the cases, there are significant
mechanistic divergences.
The genetic pathway that mediates such coordinated cell behaviors is
planar cell polarity (PCP). As its identification of this pathway in a plan
of epithelial tissue in
Drosophila
, the PCP pathway has been implicated
in the regulation of CE in mesenchymal cells of the vertebrate gastrula.
Further, there is increasing evidence that the PCP pathway is utilized in
a variety of different biological processes, in which the coordination and
orientation of cells are required within both epithelial and mesenchymal
tissues. In this review, we highlight new insights into fundamental roles
for PCP in regulating coordinated and directed cell movements in different
developmental processes. Because of space constraints, we refer for details
