Roles for the phosphatidylinositol cycle in early development.

Founded on the seminal studies and writings of Hokin, Michell and Berridge, a vast body of data now exists documenting the central importance of phosphatidylinositol (PtdIns) cycle activation in transducing information of many types across the plasma membrane. The great majority of these data derive from studies of terminally differentiated somatic cells. Nevertheless, the fact that many crucial events in animal development also involve transduction of information across the plasma membrane has recently led developmental biologists to search for regulatory roles for PtdIns cycle activity in such developmental processes as oocyte maturation, fertilization, and embryogenesis, with encouraging results. In this paper I briefly review the progress of such studies, beginning with the event in which the PtdIns cycle's role is best understood (fertilization), then progressing both backwards and forwards in developmental time to explore more speculative roles for the PtdIns cycle in oocyte maturation and pattern formation during embryogenesis.