Professor Hermann Steller and colleagues discovered how the "survival" signal SPITZ instructs developing fruit fly brain cells, called glial cells, to abort their impending suicide - an essential event in nerve cord development. Above: the nerve cord of a mutant fruit fly embryo missing the death-inducing protein Hid develops properly in the absence of a survival signal, as evident by the population of functioning glial cells (black dots) and long brain cell connections called axons (brown bands above and below the glial cells). This finding, one of several reported in the Feb. 1 issue of Developmental Cell, offers proof that SPITZ works by inactivating the death-inducing protein Hid.