Cell Competition and the Hippo Pathway

Abstract

Cell competition was discovered in Drosophila as a phenomenon whereby slow growing cells are eliminated from developing tissues. Competitive cell–cell interactions can also eliminate cells with other defects such as defects in cell polarity. Cell competition is thus regarded as a homeostatic mechanism that eliminates abnormal and potentially harmful cells. Notably, the elimination of abnormal cells by cell competition is only observed in mixed cell populations and may thus depend on specific and reciprocal cell–cell interactions. However, many questions about the mechanisms of cell competition remain. For example, what determines the competitive status of a cell and how do cells detect differences in fitness? Recent work has identified the Hippo tumor suppressor pathway as a regulator and effector of cell competition in Drosophila. In this chapter, we discuss how the Hippo pathway is linked to cell competition and how this connection may act as a tumor suppressor mechanism.