Biology subjects

Bauer, J. A.

Publications and source records attributed to Bauer, J. A..

3 recordsLinked to original sources

bioRxiv2025

High Throughput Screening Identifies a Small Molecule Trafficking Corrector for Long-QT Syndrome Associated KCNQ1 Variants

Congenital long QT syndrome (LQTS) promotes risk for life-threatening cardiac arrhythmia and sudden death in children and young adults. Pathogenic variants in the voltage-gated potassium channel KCNQ1 are the most frequently discovered genetic cause. Most LQTS-associated KCNQ1 variants cause loss-of-function secondary to impaired trafficking of the channel to the plasma membrane. There are currently no therapeutic approaches that address this underlying molecular defect. Using a high throughput screening paradigm, we identified VU0494372, a small molecule that increases total and cell surface expression, and trafficking efficiency of wildtype (WT) KCNQ1 as well as three LQTS-associated variants. Additionally, 16-hour treatment of cells with VU0494372 increased current density for WT KCNQ1 and the LQTS-associated variant V207M. VU0494372 had no impact on KCNQ1 transcription, degradation, or thermal stability. We identified a potential direct interaction site with KCNQ1 at or near the binding site of the KCNQ1 potentiator ML277. Together, these findings demonstrate that small molecules can increase the expression levels and cell surface trafficking of KCNQ1 and introduce a potential new pharmacological approach for treating LQTS.

biochemistry↗

bioRxiv2025

Pharmacological Tools to Modulate Ordered Membrane Domains and Order-Dependent Protein Function

Ordered membrane nanodomains colloquially known as "lipid rafts" have many proposed cellular functions. However, pharmacological tools to modulate protein affinity for rafts and to manipulate raft formation are currently lacking. We screened 24,000 small molecules for compounds that impact the raft affinity of a known raft-preferring protein, peripheral myelin protein 22 (PMP22), in giant plasma membrane vesicles (GPMVs). Hits were counter-screened against another raft protein, MAL, and also tested for their impact on raft stability. We identified three chemically distinct tools for manipulating lipid rafts. Two compounds were seen to both decrease PMP22 raft partitioning and to destabilize ordered domains (VU0607402 and VU0519975) while a third (primaquine diphosphate) increased PMP22 partitioning and stabilized ordered domains. While discovered in a PMP22-focused screen, all three were seen to modulate raft formation in a protein-independent manner by altering lipid-lipid interactions and membrane fluidity. Acute treatment of live cells with the raft destabilizing compound, VU0607402 was seen to modulate TRPM8 channel function, highlighting the utility of this compound in live-cell experiments for dissecting the role that membrane order and fluidity play in cell signaling. These compounds provide novel pharmacological tools for probing lipid raft properties and function in biophysical experiments and in living cells.

biophysics↗

bioRxiv2024

Small-molecule modulators of lipid raft stability and protein-raft partitioning

Development of an understanding of membrane nanodomains colloquially known as "lipid rafts" has been hindered by a lack of pharmacological tools to manipulate rafts and protein affinity for rafts. We screened 24,000 small molecules for modulators of the affinity of peripheral myelin protein 22 (PMP22) for rafts in giant plasma membrane vesicles (GPMVs). Hits were counter-screened against another raft protein, MAL, and tested for impact on raft, leading to two classes of compounds. Class I molecules altered the raft affinity of PMP22 and MAL and also reduced raft formation in a protein-dependent manner. Class II molecules modulated raft formation in a protein-independent manner. This suggests independent forces work collectively to stabilize lipid rafts. Both classes of compounds altered membrane fluidity in cells and modulated TRPM8 channel function. These compounds provide new tools for probing lipid raft function in cells and for furthering our understanding of raft biophysics. TeaserCompounds have been discovered that modulate the affinity of membrane proteins for lipid rafts as well as raft formation.

biophysics↗