Understanding how cells migrate, tumor cells invade, and organs develop their complex branched architecture has been challenging to researchers for many decades. Besides deciphering the complex underlying biochemical mechanisms and their regulation, it is now clear that it is also essential to define the roles of physical cues and cell interactions with the local microenvironment that guide these processes.
When embryonic mammalian epithelial cells need to reorganize to form the branched structures of many organs during embryonic development, they become transiently motile. This motility contributes to the plasticity and self-organization. The motile epithelial cells interact with, and locally remodel, the adjacent basement membrane in surprisingly dynamic processes involving active cell protrusions and global movements of matrix that help to sculpt developing organs. Understanding how these processes are regulated and coordinated should provide new approaches to controlling cell behavior.