Insulin signaling accelerates the anterograde movement of Rab4 vesicles in axons through Klp98A/KIF16B recruitment via Vps34-PI3Kinase

Abstract

AbstractRab4 GTPase organizes endosomal sorting essential for maintaining the balance between recycling and degradative pathways. Rab4 localizes to many cargos whose transport in neurons is critical for regulating neurotransmission and neuronal health. Furthermore, elevated Rab4 levels in the CNS are associated with synaptic atrophy and neurodegeneration inDrosophilaand humans, respectively. However, how the transport of Rab4-associated vesicles is regulated in neurons remains unknown. Usingin vivotime-lapse imaging ofDrosophilalarvae, we show that activation of insulin signaling via Dilp2 and dInR increases the anterograde velocity, run length, and flux of Rab4 vesicles in the axons. Molecularly, we show that activation of neuronal insulin signaling further activates Vps34, elevates the levels of PI(3)P on Rab4-associated vesicles, recruits Klp98A (a PI(3)P-binding kinesin-3 motor) and activates their anterograde transport. Together, these observations delineate the role of insulin signaling in regulating axonal transport and synaptic homeostasis.HighlightsDilp2-mediated insulin signaling activates anterograde transport of Rab4 vesiclesVps34 regulates anterograde velocity, run length and flux of Rab4 vesiclesLocal PI(3)P signaling on Rab4 vesicles regulates their motility in the axonsPI(3)P production upon acute insulin stimulation recruits Klp98A on Rab4 vesicles