JAK-STAT Signal Inhibition Regulates Competition in the Drosophila Testis Stem Cell Niche

Stemming Stem Cell Displacement Adult stem cell niches can contain multiple types of stem cells with coordinated regulation, but the mechanisms for these interactions are largely unknown. In the fruit fly testis, Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling is needed for the maintenance of the resident germline and somatic stem cells. The signaling inhibitor SOCS36E is a known JAK-STAT target. Issigonis et al. (p. 153 ) now show that SOCS36E functions in the maintenance of the germline stem cell via suppression of JAK-STAT signaling, specifically in the somatic stem cells. This prevents the somatic stem cells from displacing neighboring germline stem cells in an integrin-dependent manner, allowing both stem cell populations to occupy the niche.