Visualizing the Multistep Process of Protein Aggregation in Live Cells

• DOI: 10.1021/acs.accounts.1c00648
• Publication Date: 2022-01-18T13:13:33Z
• Authors: Songtao Ye; Chia-Heng Hsiung; Yuqi Tang; Xin Zhang
• Keywords: 0301 basic medicine; Amyloid; Protein Aggregates; Protein Folding; 03 medical and health sciences; Spectrometry, Fluorescence; Hydrolases; Cells; Humans; Biosensing Techniques; Fluorescent Dyes

Protein aggregation is a biological phenomenon in which aberrantly processed or mutant proteins misfold and assemble into variety of insoluble aggregates. Decades studies have delineated the structure, interaction, activity either their natively folded structures aggregates such as amyloid fibrils. However, intermediate species exist between these two extreme states protein folding landscape. Herein, we collectively term misfolded oligomers, including soluble oligomers preamyloid that are formed by unfolded proteins. While extensive tools been developed to study fibrils, research understand properties activities has limited lack methods detect interrogate live cells.In this Account, describe our efforts development chemical allow for characterization multistep process, particular living cells. As start journey, attempted develop fluorogenic method wherein could turn on fluorescence probes conjugated protein-of-interest (POI). To end, produced series destabilized HaloTag variants, formulating primary component AgHalo sensor, misfolds when cells subjected stress. When covalently with solvatochromic fluorophore, misfolding conjugate would activate fluorescence, resulting observation oligomers. Following work, extended scope detection from any via AggTag method, POIs genetically fused self-labeling tags (HaloTag SNAP-tag). Focusing molecular rotor-based fluorophores, applied modulated fluorescent (FP) chromophore core prototype probes, enable multiple Next, further distinguish using classes different emission toward conformations. goal, physical organic chemistry computational discover new category triode-like π orbitals an electron density regulator donor-acceptor linkages used control rotational barriers fluorophores excited states. This mechanism allows us rationally design desired responses viscosity, thus extending application method.In summary, work direct monitoring differentiation other conformations cells, enabling many currently unanswered questions aggregation. Future directions quantitative analyses process. Further, needed quantify formation maturation RNA condensates form membraneless organelles.