Katie DeLong

All Publications

• SNARE disassembly requires Sec18/NSF side loading. Nature structural & molecular biology Khan, Y. A., White, K. I., Pfuetzner, R. A., Singal, B., Esquivies, L., Mckenzie, G., Liu, F., DeLong, K., Choi, U. B., Montabana, E., Mclaughlin, T., Wickner, W. T., Brunger, A. T. 2025

  Abstract

  SNARE (soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor) proteins drive membrane fusion at different cell compartments as their core domains zipper into a parallel four-helix bundle. After fusion, these bundles are disassembled by the AAA+ (ATPase associated with diverse cellular activities) protein Sec18/NSF and its adaptor Sec17/α-SNAP to make them available for subsequent rounds of membrane fusion. SNARE domains are often flanked by C-terminal transmembrane or N-terminal domains. Previous structures of the NSF-α-SNAP-SNARE complex revealed binding to the D1 ATPase pore, posing a topological constraint as SNARE transmembrane domains would prevent complete substrate threading as suggested for other AAA+ systems. Using mass spectrometry in yeast cells, we show N-terminal SNARE domain interactions with Sec18, exacerbating this topological issue. We present cryo-electron microscopy (cryo-EM) structures of a yeast SNARE complex, Sec18 and Sec17 in a nonhydrolyzing condition, which show SNARE Sso1 threaded through the D1 and D2 ATPase rings of Sec18, with its folded, N-terminal Habc domain interacting with the D2 ring. This domain does not unfold during Sec18/NSF activity. Cryo-EM structures under hydrolyzing conditions revealed substrate-released and substrate-free states of Sec18 with a coordinated opening in the side of the ATPase rings. Thus, Sec18/NSF operates by substrate side loading and unloading topologically constrained SNARE substrates.

  View details for DOI 10.1038/s41594-025-01590-w

  View details for PubMedID 40604310

  View details for PubMedCentralID 2488960

• Dpr10 and Nocte are required for Drosophila motor axon pathfinding. Neural development Lobb-Rabe, M., DeLong, K., Salazar, R. J., Zhang, R., Wang, Y., Carrillo, R. A. 2022; 17 (1): 10

  Abstract

  The paths axons travel to reach their targets and the subsequent synaptic connections they form are highly stereotyped. How cell surface proteins (CSPs) mediate these processes is not completely understood. The Drosophila neuromuscular junction (NMJ) is an ideal system to study how pathfinding and target specificity are accomplished, as the axon trajectories and innervation patterns are known and easily visualized. Dpr10 is a CSP required for synaptic partner choice in the neuromuscular and visual circuits and for axon pathfinding in olfactory neuron organization. In this study, we show that Dpr10 is also required for motor axon pathfinding. To uncover how Dpr10 mediates this process, we used immunoprecipitation followed by mass spectrometry to identify Dpr10 associated proteins. One of these, Nocte, is an unstructured, intracellular protein implicated in circadian rhythm entrainment. We mapped nocte expression in larvae and found it widely expressed in neurons, muscles, and glia. Cell-specific knockdown suggests nocte is required presynaptically to mediate motor axon pathfinding. Additionally, we found that nocte and dpr10 genetically interact to control NMJ assembly, suggesting that they function in the same molecular pathway. Overall, these data reveal novel roles for Dpr10 and its newly identified interactor, Nocte, in motor axon pathfinding and provide insight into how CSPs regulate circuit assembly.

  View details for DOI 10.1186/s13064-022-00165-5

  View details for PubMedID 36271407

  View details for PubMedCentralID PMC9585758