Project Summary / Abstract
Elucidating the molecular mechanisms that respond to membrane voltage changes at neuronal synapses and
link these changes to the appropriate cellular responses is critical to physiology, as neural circuitry must
maintain homeostasis while adapting to novel conditions, as well as in relation to neurological and
neurodegenerative diseases, many of which ultimately result from defective synaptic transmission. Drosophila
melanogaster has emerged as a powerful genetic model for dissecting such mechanisms. While significant
progress has been made in identifying the structural components of synapses, as well as the molecules used
by pre- and postsynaptic cells to communicate across the synaptic cleft, the mechanism by which these
cellular processes integrate with transient changes in membrane voltage remain poorly understood. The
current proposal will address this knowledge gap by focusing on how a noncanonical localized form bone
morphogenetic protein (BMP) signaling at synapses serves as a sensor for membrane voltage, and the
potential for this form of signaling to serve as an adapter between transient membrane voltage changes and
more stable cellular alterations. We will test three central hypotheses: 1) that local BMP signaling responds to
voltage changes at synapses; 2) that synaptic BMP signaling dynamically rises and falls in response to acute
changes in membrane voltage; and 3) that synaptic BMP signaling complexes interact with a distinct suite of
regulatory and effector molecules. These hypotheses will be tested by using a combination of in vivo genetics,
gene editing, immunofluorescent microscopy, electron microscopy, molecular biology, biochemistry, and
electrophysiology methods. The short-term impact of these studies will be novel insights into the molecular
machinery linking membrane voltage changes with cellular and molecular alterations at Drosophila
neuromuscular junction synapses. Ultimately, these studies may identify evolutionary conserved regulatory
mechanisms with an important role in synaptic physiology in humans, and potentially contribute to our
understanding of how disruptions in these cellular processes underlie the pathophysiology of neurological and
neurodegenerative disease states.