Investigation of SYD-2 Liprin-alpha Ubiquination by the Anaphase-Promoting Complex in C. elegans Motor Neurons

Taylor Prechtel Butler University, Lauryn Campagnoli Butler University, Daniel Lester Butler University, Kristen Rush Butler University
Faculty Sponsor(s): Jennifer Kowalski Butler University
Proper nervous system function relies on a tight balance of excitatory to inhibitory (E:I) signaling, which is regulated by the activity of numerous synaptic proteins. Ubiquitination is one process used to control protein levels and activity. E:I imbalances and ubiquitin (Ub) system defects are present in several neurological disorders. We use the neuromuscular junction (NMJ) in Caenorhabditis elegans roundworms as a model to study Ub and E:I balance. At the C. elegans NMJ, excitatory acetylcholine (Ach) signaling causes muscle excitation and inhibitory GABA signaling causes muscle relaxation. We previously used aldicarb assays, which measure net muscle excitation, to characterize the role of a conserved Ub ligase, the Anaphase-promoting complex (APC), in controlling E:I balance in GABA motor neurons. Our data support a model in which the APC indirectly promotes GABA release to prevent excess muscle contraction by acting to down-regulate an intermediate substrate(s). SYD-2 is a potential substrate of the APC that localizes to presynaptic sites and contains APC recognition sequences (D-boxes). Previous behavioral and imaging experiments support the hypothesis that SYD-2 acts downstream of the APC at the NMJ. If our hypothesis is correct, I expect ub-SYD-2 levels to fall and overall SYD-2 abundance to increase in animals lacking APC function. Biochemical experiments are underway using GFP-Trap Beads and Tandem Ubiquitin Binding Entities (TUBES) to isolate Ub-tagged GFP::SYD-2 and Western blotting techniques for protein identification. These studies are critical to determine if SYD-2 is a neuronal substrate for the APC.
Oral Presentation

When & Where

09:15 AM
Gallahue Hall 105