The Gumucio and Kalantry laboratories have found that dissociated pluripotent stem cells (both human and mouse) readily apically polarize and form lumens. Even before polarization is evident, a highly organized intracellular perinuclear structure forms; this structure has a core of apical proteins and is surrounded by basolateral proteins and apical organelles (Golgi, Rab 11 vesicles). Importantly, formation of this structure is associated with cell survival (it is therefore called a suvivosome). During cytokinesis, this structure is not dissociated; it is inherited in an assymetric manner and is eventually inserted into the cytokinetic plane. We will investigate the factors that account for its link to cell survival (Gumucio), its relevance in the early mouse embryo (Kalantry) and its inheritance during cytokinesis (Miller). Our hypothesis is that this structure facilitates an intracellular FGF-mediated signaing loop that is important for cell survival.