Biology

Dr. Sudip Mandal
IISER Mohali

Abstract:

Reactive Oxygen Species (ROS) are partially reduced and highly reactive derivates of oxygen. Though ROS has been known for its damaging roles, it is widely appreciated that controlled amount of ROS actually controls various cellular processes. Employing in vivo genetic studies in Drosophila we show that besides causing G1-S arrest by activation of Dacapo, as evidenced earlier, ROS can simultaneously inhibit cell growth by regulating the expression of 4EBP and S6K. This is achieved by triggering a signaling cascade that includes Ask1, JNK and FOXO independent of the Tsc-TOR growth regulatory pathway. Importantly, during normal development high levels of ecdysone activates this pathway in late larval fat body cells prior to pupation. In doing so, it imposes a growth arrest for the larval fat body cells, which is eventually critical for determining the organismal size. Thus this study unravels an otherwise unknown physiologically relevant mechanism by which the redox state modulates the gene regulatory network integrating ecdysone and insulin signaling to regulate systemic growth.