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express ephrins. In this way we can precisely control the levels of ephrins
involved in the interaction, and investigate possible differences in response to
different A-ephrins.
It is interesting to view the interaction of Eph receptor-expressing neurons
with ephrin-expressing fibroblasts in the light of the work of Michael
Abercrombie. During the phenomenon of contact inhibition of locomotion in
cultured cells, he described how dynamic actin structures such as lamellipodia
are paralysed at new cell contact sites. Overall this can lead to the migration of
contacting cells away from one another. The signalling pathways involved
must therefore converge on the actin cytoskeleton and cell adhesion systems in
both cells involved in the interaction. In the co-culture assay described here
both cells respond by remodelling their actin based motility machineries, and
ultimately pull away from the site of contact. It may turn out to be that similar
mechanisms are involved in Eph receptor/ephrin regulated cell repulsion and
Abercrombie's contact inhibition of locomotion.
References
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