Engineers at Penn have developed an innovative method that transcends the inherent limitations of traditional light microscopy to illuminate the tiniest of protein assemblies, facilitating the identification of proteins linked to disorders such as Alzheimer’s, and paving the way for the exploration of novel treatments.
In their study published in Cell Systems, Lukasz Bugaj, an Assistant Professor of Bioengineering, introduced CluMPS (Clusters Magnified by Phase Separation). This revolutionary molecular mechanism reveals itself by forming distinct aggregates when it encounters specific protein assemblies, even as small as a few nanometers across. Essentially, CluMPS operates as a binary switch, activating in the presence of the protein clusters it is designed to detect.
Under conventional circumstances, identifying such minuscule clusters is a cumbersome process. "With CluMPS, you eliminate the need for anything more than a basic laboratory microscope," explains Bugaj. This mechanism combines with the protein of interest to generate condensates significantly larger than the original clusters, resembling the vibrant formations seen in a lava lamp. "Its straightforwardness is a major advantage," remarks Bugaj. "Without requiring specialized expertise or equipment, one can easily ascertain the presence of tiny clusters within cells."
Revolutionizing Disease Treatment and Pharmaceutical Research
- The ability to identify protein assemblies of such diminutive size holds tremendous promise for advancing the treatment of diseases including Alzheimer’s, ALS, and cancer.
- It enables scientists to verify whether medications are effective in eradicating the protein clusters that contribute to disease within cells.
"A clear indication is essential to ascertain the success of a treatment," according to Bugaj. "Identifying large clusters is straightforward, but pinpointing smaller ones is considerably more challenging. Now, we have the means to enhance this signal, allowing us to observe which treatments successfully break down these clusters."
The visualization of protein clusters facilitated by CluMPS is depicted through red and cyan dots. Credit: Thomas R. Mumford
Beyond facilitating drug development, CluMPS offers insights into protein behavior, enriching our understanding of cellular processes. "There exists a vast, yet undiscovered world of protein clustering at the microscale, which is crucial but currently not well understood," states Bugaj.
Addressing Technical Hurdles
A significant obstacle that CluMPS addresses is the inability of light wavelengths, which are broader than the smallest protein clusters, to adequately visualize these assemblies. "Blue light has a wavelength of approximately 400 nanometers," notes Bugaj. "Anything smaller than half of this wavelength cannot be accurately located with a standard microscope," making it nearly impossible to observe clusters only tens of nanometers in size.
In the development of CluMPS, Bugaj collaborated with Elizabeth Rhoades, a Chemistry Professor at Penn Arts & Sciences. Rhoades’ lab confirmed that CluMPS accurately identifies targeted protein clusters without producing false positives. "This collaboration was immensely gratifying," comments Rhoades, "as it allowed us to apply our lab's techniques to authenticate this innovative tool in live cells, clearly distinguishing between clusters and individual proteins."
Thomas R. Mumford, a doctoral candidate in Bugaj’s team and the primary author of the study, was instrumental in devising and conducting experiments. "It was imperative to understand how CluMPS interacts with protein clusters to induce condensation," reflects Mumford, ensuring that future users grasp the tool’s functionality. "We had to prove that we were indeed detecting small clusters," adds Bugaj, "Collaborating with Tom and the Rhoades lab to design experiments that conclusively demonstrated this was incredibly fulfilling."