AMPylation and Neurotransmitter Recycling
AMPylation, the covalent addition of adenosine 5'-monophosphate (AMP) to hydroxyl groups, is a recently appreciated post-translational modification by which bacterial Fic domain proteins regulate small GTPases. To explore the function of eukaryotic Fic domains we generated fic null mutants. We discovered a role of AMPylation in the Drosophila visual system: Fic-mediated AMPylation in glia is necessary for normal recycling of the histamine neurotransmitter. How AMPylation of glial proteins contributes to neurotransmitter recycling is a focus of our investigations.
Drosophila Fic is an ER protein highly expressed in the glia of the visual system and enriched in capitate projections, cytosolic “fingers” that glia extends into the axonal endings of photoreceptors.