Biomedical Engineering Reference
In-Depth Information
Figure 2.2.
Schematics of a keratocyte cell. A top-view (upper scheme) and side-
view (lower left) of a keratocyte showing the cell body that contains the nucleus
and all the organelles, and the broad, thin, fan-shaped lamellipodium up front.
The gray arrow indicates the direction of cell movement. The scheme illustrates
the localization of various components, including the dendritic actin network in
the lamellipodium, myosin clusters in the lamellipodium and in an actin-myosin
bundle at the rear, adhesion complexes, the cell membrane, and the cytosolic fluid.
An enlarged scheme of the leading edge (lower right) depicts, roughly to scale,
the number of barbed ends of actin filaments at the leading edge, and the black
arrowheads indicate monomer assembly onto barbed ends. The enlarged scheme of
the leading edge was reproduced and modified from [42] with copyright permission
of The Biophysical Society.
discuss the role of the three main mechanical modules involved in keratocyte
motility, which include the actin-myosin cytoskeleton, the cell membrane, and
the cytoplasmic fluid (see Figure 2.2), while providing only a limited account
of the molecular basis of cell motility (the interested reader is referred to
other reviews, e.g., [1, 5, 6, 7, 45]). We describe our current understanding of
the properties of each module and discuss the coupling between them. At the
same time we highlight the gaps in our current knowledge and point out areas
where further experimental and theoretical efforts are needed. The chapter
is ordered as follows. In Section 2.2 we discuss the actin-myosin cytoskeleton
