5 research outputs found
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Zebrafish behavioural profiling identifies GABA and serotonin receptor ligands related to sedation and paradoxical excitation.
Anesthetics are generally associated with sedation, but some anesthetics can also increase brain and motor activity-a phenomenon known as paradoxical excitation. Previous studies have identified GABAA receptors as the primary targets of most anesthetic drugs, but how these compounds produce paradoxical excitation is poorly understood. To identify and understand such compounds, we applied a behavior-based drug profiling approach. Here, we show that a subset of central nervous system depressants cause paradoxical excitation in zebrafish. Using this behavior as a readout, we screened thousands of compounds and identified dozens of hits that caused paradoxical excitation. Many hit compounds modulated human GABAA receptors, while others appeared to modulate different neuronal targets, including the human serotonin-6 receptor. Ligands at these receptors generally decreased neuronal activity, but paradoxically increased activity in the caudal hindbrain. Together, these studies identify ligands, targets, and neurons affecting sedation and paradoxical excitation in vivo in zebrafish
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Influenza M2 generates negative gaussian curvature through lipid tilt anisotropy; Advances in zebrafish chemobehavioral phenomics reveal novel neuroactive
The twin subjects of this dissertation may seem far flung, but they are unified by a commonpurpose. I like stories that start with molecules and end with things everyone has directly
experienced. That is, Iâm interested in bridging the gaps between macro-scale physiology
and molecular sciences, that we might give an account of our immediate experiences on a
solid foundation. Each project involved completely different collaborators and methods,
but both were integral to my time at UCSF and directed by the same underlying curiosity.
One crucial question at this meso-scale interface is how proteins deform and ultimately
determine the fate of membranes. An exemplary membrane-deforming protein is the
M2 proton channel, produced by influenza to help the virus escape the host cell. I
combined molecular dynamics simulations with diverse experimental measurements to
better understand the structural principles that allow M2 to bind curved membranes and
facilitate the release of new virions. In unbiased simulations, I find that M2 spontaneously
loses its initial four-fold symmetry to become at most two-fold symmetric. This dynamical
property seemed potentially connected to its ability to accommodate negative Gaussian
curvature (a saddle-shaped membrane geometry). Additional simulations agree with
continuum membrane calculations that two-fold symmetry is better adapted to saddleshaped
membranes, suggesting that symmetry degeneration is a key part of M2âs function in
viral egress. Therapeutics may one day be able to alter this property and inhibit influenza
egress. These findings may be generalizable to other viroporins like the SARS-CoV2 E
protein.
Another key meso-scale question is how neuroactive drugs give rise to behavioral changes in
animals. I helped develop a platform for investigating drug-induced behavioral phenotypes
in larval zebrafish at scale in order to begin quantitative mapping between chemical matter
(drugs) and simple but fundamental behaviors like sedation and habituation. We find
that known drugs habituation modifiers (like MK-801) are effective in the larval zebrafish
model, and identified several new lead compounds from libraries with similar effects. Such
drugs may hold promise as treatments for addiction and neurodegeneration
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Extending chemical perturbations of the ubiquitin fitness landscape in a classroom setting reveals new constraints on sequence tolerance.
Although the primary protein sequence of ubiquitin (Ub) is extremely stable over evolutionary time, it is highly tolerant to mutation during selection experiments performed in the laboratory. We have proposed that this discrepancy results from the difference between fitness under laboratory culture conditions and the selective pressures in changing environments over evolutionary timescales. Building on our previous work (Mavor et al., 2016), we used deep mutational scanning to determine how twelve new chemicals (3-Amino-1,2,4-triazole, 5-fluorocytosine, Amphotericin B, CaCl2, Cerulenin, Cobalt Acetate, Menadione, Nickel Chloride, p-Fluorophenylalanine, Rapamycin, Tamoxifen, and Tunicamycin) reveal novel mutational sensitivities of ubiquitin residues. Collectively, our experiments have identified eight new sensitizing conditions for Lys63 and uncovered a sensitizing condition for every position in Ub except Ser57 and Gln62. By determining the ubiquitin fitness landscape under different chemical constraints, our work helps to resolve the inconsistencies between deep mutational scanning experiments and sequence conservation over evolutionary timescales
Extending chemical perturbations of the ubiquitin fitness landscape in a classroom setting reveals new constraints on sequence tolerance
Although the primary protein sequence of ubiquitin (Ub) is extremely stable over evolutionary time, it is highly tolerant to mutation during selection experiments performed in the laboratory. We have proposed that this discrepancy results from the difference between fitness under laboratory culture conditions and the selective pressures in changing environments over evolutionary timescales. Building on our previous work (Mavor et al., 2016), we used deep mutational scanning to determine how twelve new chemicals (3-Amino-1,2,4-triazole, 5-fluorocytosine, Amphotericin B, CaCl2, Cerulenin, Cobalt Acetate, Menadione, Nickel Chloride, p-Fluorophenylalanine, Rapamycin, Tamoxifen, and Tunicamycin) reveal novel mutational sensitivities of ubiquitin residues. Collectively, our experiments have identified eight new sensitizing conditions for Lys63 and uncovered a sensitizing condition for every position in Ub except Ser57 and Gln62. By determining the ubiquitin fitness landscape under different chemical constraints, our work helps to resolve the inconsistencies between deep mutational scanning experiments and sequence conservation over evolutionary timescales
Recommended from our members
Extending chemical perturbations of the ubiquitin fitness landscape in a classroom setting reveals new constraints on sequence tolerance.
Although the primary protein sequence of ubiquitin (Ub) is extremely stable over evolutionary time, it is highly tolerant to mutation during selection experiments performed in the laboratory. We have proposed that this discrepancy results from the difference between fitness under laboratory culture conditions and the selective pressures in changing environments over evolutionary timescales. Building on our previous work (Mavor et al., 2016), we used deep mutational scanning to determine how twelve new chemicals (3-Amino-1,2,4-triazole, 5-fluorocytosine, Amphotericin B, CaCl2, Cerulenin, Cobalt Acetate, Menadione, Nickel Chloride, p-Fluorophenylalanine, Rapamycin, Tamoxifen, and Tunicamycin) reveal novel mutational sensitivities of ubiquitin residues. Collectively, our experiments have identified eight new sensitizing conditions for Lys63 and uncovered a sensitizing condition for every position in Ub except Ser57 and Gln62. By determining the ubiquitin fitness landscape under different chemical constraints, our work helps to resolve the inconsistencies between deep mutational scanning experiments and sequence conservation over evolutionary timescales