The two faces of TOE-2.

The C. elegans Q lineage provides a unique context for studying how cells divide asymmetrically to generate cells fated to die. The Q cell divides to form the Q.a and Q.p neuroblasts, each of which divides to produce neurons and a cell that dies by apoptosis; however, these neuroblasts employ different mechanisms to divide asymmetrically.(1) We discovered 2 distinct roles for TOE-2, a protein previously shown to be a target of the C. elegans ERK ortholog MPK-1, in promoting apoptosis in each of these neuroblast divisions. In this commentary, we discuss possible molecular mechanisms by which TOE-2 promotes apoptosis. Specifically, we will discuss potential roles for TOE-2 interacting proteins, a possible nuclear function for TOE-2, and a potential link to the Wnt pathway.