Journal of Cell Science 115, e1203-e1203 (2002)
© 2002 The Company of Biologists Limited
Integrins: three is the magic number
The ability of cell surface integrins to link the extracellular matrix
(ECM) to the actin cytoskeleton is central to cell motility: if an
ECM-anchored integrin is attached to the cytoskeleton, the cytoskeleton can
pull on it and so drive the cell forward. Cytoskeletal attachment appears to
require integrin clustering, but how big must each cluster be? Harold Erickson
and co-workers have approached this question by examining the number of
integrin molecules needed to translocate fibronectin-coated beads across the
surface of a cell at constant velocity — an assay for cytoskeletal
attachment (see p. 2581). They
find that beads coated with fibronectin constructs containing three or five
cell-adhesion domains, which should produce clusters of three and five
integrins, respectively, bind strongly to and translocate across the cell
surface. Fibronectin constructs containing one or two adhesion domains (which
would form only integrin monomers/dimers) by contrast exhibit only brief
binding and random movement. A cluster of at least three integrins thus seems
to be required for productive cytoskeletal interactions — which is an
interesting contrast to the paradigm of receptor dimerization in
signalling.
Related articles in JCS:
- Trimers of the fibronectin cell adhesion domain localize to actin filament bundles and undergo rearward translocation
- Françoise Coussen, Daniel Choquet, Michael P. Sheetz, and Harold P. Erickson
JCS 2002 115: 2581-2590.
[Abstract]
[Full Text]
