A Versatile Semester-Long Course-Based Undergraduate Research Experience using Optogenetics and RNAi to Identify Genes Important for Synapse Function.

Compared to traditional teaching laboratory activities, course-based undergraduate research experiences (CUREs) can increase student engagement and confidence, improve scientific literacy, enhance critical thinking, and promote accessibility in STEM. Here we describe a versatile CURE for an upper-level Neurobiology course that incorporates genetic, molecular, cellular, and behavioral experiments into a semester-long investigation to identify genes important for glutamate synapse formation or function in . Following introduction to the CURE approach and basic techniques, students construct their own low-cost optogenetics rigs, which we describe in detail here, to activate a mechanosensory escape reflex via photostimulation.

Regulation of AMPA receptor trafficking by secreted protein factors.

AMPA receptors (AMPARs) mediate the majority of fast excitatory transmission in the brain. Regulation of AMPAR levels at synapses controls synaptic strength and underlies information storage and processing. Many proteins interact with the intracellular domain of AMPARs to regulate their trafficking and synaptic clustering.

Low-Density Lipoprotein Receptor LRP-2 regulates GLR-1 glutamate receptors and glutamatergic behavior in .

We identified the Low-Density Lipoprotein (LDL) Receptor Related Protein-2 (LRP-2) in a RNAi screen for genes that regulate glutamatergic behavior in . loss-of-function mutants have defects in glutamatergic mechanosensory nose-touch behavior and suppress increased spontaneous reversals induced by GLR-1(A/T), a constitutively-active form of the AMPA-type glutamate receptor GLR-1. Total and surface levels of GLR-1 are increased throughout the ventral nerve cord of mutants suggesting that LRP-2 promotes glutamatergic signaling by regulating some aspect of GLR-1 trafficking, localization or function.

The WD40-Repeat Protein WDR-20 and the Deubiquitinating Enzyme USP-46 Promote Cell Surface Levels of Glutamate Receptors.

Reversible modification of AMPA receptors (AMPARs) with ubiquitin regulates receptor levels at synapses and controls synaptic strength. The conserved deubiquitinating enzyme (DUB) ubiquitin-specific protease-46 (USP-46) removes ubiquitin from AMPARs and protects them from degradation in both and mammals. Although DUBs are critical for diverse physiological processes, the mechanisms that regulate DUBs, especially in the nervous system, are not well understood.