Dynamin-dependent endocytosis is necessary for convergent-extension movements in Xenopus animal cap explants

Cadherin cell-cell adhesion molecules are important determinants of morphogenesis and tissue patterning. C-cadherin plays a key role in the cell-upon-cell movements seen during Xenopus gastrulation. In particular, regulated changes in C-cadherin adhesion critically influence convergence-extension movements, thereby determining organization of the body plan. It is also predicted that remodelling of cadherin adhesive contacts is important for such cell-on-cell movements to occur. The recent demonstration that Epithelial (E-) cadherin is capable of undergoing endocytic trafficking to and from the cell surface presents a potential mechanism for rapid remodelling of such adhesive contacts. To test the potential role for C-cadherin endocytosis during convergence-extension, we expressed in early Xenopus embryos a dominantly-inhibitory mutant of the GTPase, dynamin, a key regulator of clathrin-mediated endocytosis. We report that this dynamin mutant significantly blocked the elongation of animal cap explants in response to activin, accompanied by inhibition of C-cadherin endocytosis. We propose that dynamin-dependent endocytosis of C-cadherin plays an important role in remodelling adhesive contacts during convergence-extension movements in the early Xenopus embryo.