Stick-slip motion and elastic coupling in crawling cells

Abstract

Crawling cells exhibit a variety of cell shape dynamics, ranging from complex ruffling and bubbling to oscillatory protrusion and retraction. Periodic shape changes during cell migration are recorded in fast-moving fish epithelial keratocytes where sticking and slipping at opposite sides of the cell's broad trailing edge generate bipedal locomotion. Barnhart et al. [Biophys. J. 98, 933 (2010)] recently proposed a mechanical spring model specifically designed to capture bipedal locomotion in these cells. We extend their model by benchmarking the dynamics of four mechanical configurations against those of crawling keratocytes. Our analysis shows that elastic coupling to the cell nucleus is necessary to generate its lateral motion. We select one configuration to study the effects of cell elasticity, size, and aspect ratio on crawling dynamics. This configuration predicts that shape dynamics are highly dependent on the lamellipodial elasticity but less sensitive to elasticity at the trailing edge. The model predicts a wide range of dynamics seen in actual crawling keratocytes, including coherent bipedal, coherent nonbipedal, and decoherent motions. This work highlights how the dynamical behavior of crawling cells can be derived from mechanical properties through which biochemical factors may operate to regulate cellular locomotion.

Effects of Adhesion Dynamics and Substrate Compliance on the Shape and Motility of Crawling Cells

“…Second, such an extension can possibly allow for a more accurate description of the bipedal motion of keratocytes observed in Refs. [45], [46]. In this respect it is interesting to note that our model shows a regime reminiscent of the bipedal (rocking) motion, when the cell moves on adhesive stripes, see Fig.…”

Mechanics of motility initiation and motility arrest in crawling cells

“…Denote by l − (t) and l + (t) the rear and front boundaries of our gel segment. To account for cortex/membrane elasticity we assume, as in the discrete model, that the boundaries are linked through a linear spring (Barnhart et al, 2010;Du et al, 2012;Loosley and Tang, 2012;Recho and Truskinovsky, 2013). This assumption affects the values of the stress in the moving points l − (t) and l + (t):…”

Modeling crawling cell movement on soft engineered substrates

“…Especially, we have found a "bipedal"-like motion displaying periodic out-of-phase retractions of the trailing edges of the cell, similar to that recently found experimentally. 18,19 The fact that motile cells have to navigate in complex environment (e.g. inside blood vessels or tissue) has inspired the studies of microswimmers moving through array of obstacles, 20 for the purpose of sorting and separation, 21 for rectication in ratchet-like channels or pumping uid.…”