During the development of vertebrates large numbers of cells migrate to new locations in the body. Cell migration is driven by complex mechanical forces and is under precise molecular regulation. This proposal focuses on the molecular regulation of cellular contractility driven my actin and myosin. This constrictive power is one of the primary driving forces of cell movement. To understand how cells regulate their contractility it is necessary to study live cells in a living organism. Zebrafish provide an ideal and cost-effective experimental model system for the study of cell movement and much of what we learn in zebrafish can be translated to understanding human biology. Unlike mammals zebrafish embryos are fertilized externally and are optically transparent during early development. One can directly observe cell movement and behavior using standard microscopy without any invasive procedures. This project uses a combination of biochemical, genetic, cell biological and developmental approaches to examine the role of the myosin phosphatase complex in controlling cell movement. The outcomes of this proposal are expected to shed new light on how cells regulate their movement in complex environments. This project involves the training of undergraduate and master?s students. These students will gain valuable experience in hands on data collection and experimental design which assistant them in their future careers in research or medical fields. In addition this project will synergize with advanced undergraduate coursework at University of the Pacific such as cell biology and molecular biology, allowing students to use zebrafish as part of there in class research projects.