Inhibits cell growth by regulating the Tor pathway upstream of the Tsc1-Tsc2 complex and downstream of Akt1. Acts as cell death activator during head development. Expression peaks 2-8 hours after egg laying. Expressed in the dorsal domains of gastrulation stage embryos. During mid-embryonic development, expressed in the central nervous system, the three thoracic segments and the cardiac precursor cells. Expression is controlled by homeobox transcription factors. At larval stages, induced by starvation, and mildly by hypoxia in midgut but not fat body. Belongs to the DDIT4 family.