Published online by Cambridge University Press: 03 February 2010
We present a simple mechanism of cell motility in a confined geometry, inspired by recentmotility assays in microfabricated channels. This mechanism relies mainly on the couplingof actin polymerisation at the cell membrane to geometric confinement. We first showanalytically using a minimal model of polymerising viscoelastic gel confined in a narrowchannel that spontaneous motion occurs due to polymerisation alone. Interestingly, thismechanism does not require specific adhesion with the channel walls, and yields velocitiespotentially larger than the polymerisation velocity of the gel. We then study the effectof the contractile activity of myosin motors, and show that whilst it is not necessary toinduce motion, it quantitatively increases the velocity of motion in the polymerisationmechanism we describe. Our model qualitatively accounts for recent experiments which showthat cells without specific adhesion proteins are motile only in confined environmentswhile they are unable to move on a flat surface. It also constitutes a first step in thestudy of cell migration in more complex confined geometries such as living tissues.