Biophysical Society Conference | Tahoe 2024

Molecular Biophysics of Membranes

Poster Abstracts

3-POS Board 1 CHANGES IN ENVIRONMENTAL CONDITIONS DIFFERENTIALLY AFFECT SNAP-25 ISOFORMS Tanner M Blocker 1 ; Thomas D Weed 1 ; Jason T Carlson 1 ; Joseph H Jackson 1 ; Jarom S Sumsion 1 ; Samuel W Shumway 1 ; Hunter S Malquist 1 ; Dixon J Woodbury 1 ; 1 Brigham Young University, Cell Biology and Physiology, Provo, UT, USA In the brain, neurons communicate via releasing and detecting neurotransmitters. Release occurs through exocytosis following fusion of synaptic vesicles to neuronal cell membranes. This process is driven by formation of a dynamic quaternary protein structure known as the SNARE complex. SNAP-25 contributes two (of four) alpha helical domains to the SNARE complex. Neurons express SNAP-25 in two isoforms, SNAP-25A (25A) and SNAP-25B (25B) which appear to function similarly. These two isoforms vary by just 9 amino acids and are expressed differently depending on brain region and the developmental stage of the neuron (Bark et al. PNAS, USA. 92:1510). The amino acid sequences of 25A and 25B and their effect on SNARE complex stability have been studied (Nagy et al, 2005, Molecular Biology of the Cell, Vol. 16:5675). However, the difference in secondary structures of 25A and 25B remains unclear. Using circular dichroism (CD) spectroscopy, we show that SNAP- 25A and 25B are differentially altered by temperature, redox state, and alcohol. We hypothesize these differences provide neurons alternative responses depending on environmental stresses encountered during stages of development and in different regions of the brain.

80