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Researchers Identify BeeR, a Novel Protein That May Enhance Drug Delivery in Cancer Care
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BeeR is a bacterial protein from the family Verrucomicrobiota that influences cell shape and division.
Cancer drugs are ever evolving between new agents and new treatment approaches. Continuing in these efforts, researchers from King’s College London and the University of Washington identified a previously unknown bacterial protein whose structure is being utilized to create protein nanoparticles that carry anticancer medications to tumors more selectively. Their findings provide foundational knowledge that could inform more innovative development of targeted therapies for cancer and other diseases.
Close-up of actin and myelin filaments weaved together | Image Credit: © Shutter2U - stock.adobe.com
Actin is the most abundant protein in the majority of human cells and plays a critical role in cell structure and function. When in the presence of adenosine triphosphate (ATP), the molecules come together to form filaments. In eukaryotic cells, this activity serves as the foundation for many cellular functions, such as signal transduction, intracellular transport, cell migration, muscle contraction, and cell division.1,2
To identify actin-like proteins, the team used metagenomics data and identified BeeR (Bacterial elongated entwined Rail-like protein) as a distinct family of bacterial proteins known as Verrucomicrobiota. BeeR has a similar function to actin and can form filaments in the presence of ATP to control cell shape and division. However, using cryo-electron microscopes, researchers discovered it has notable differences in its atomic structure. Rather than forming filaments, BeeR forms a rigid tube, with a hollow cavity at its center.1,2
“Not only are the BeeR structures tubular, but they also have a cavity at their center that is big enough to contain drug molecules. Since we can easily control the assembly and disassembly of the tube with ATP, it gives us a simple method to deliver and release the drugs at the desired location,” explained Julien Bergeron, MD, senior lecturer in the Randall Centre for Cell & Molecular Biophysics at King’s College London, who led the research.2
The structural features of BeeR, including a diameter of approximately 80 Å and a central cavity of about 25 Å, suggest that it may provide a more rigid filament compared to other actin homologs. The protein has a flexible and unstructured region at its beginning that does not fold into a fixed shape. This disordered region seems to stop multiple protein filaments from clustering together. However, the specific biological functions of the BeeR filaments remain to be fully understood.1,2
The study of bacterial actin homologs, such as BeeR, expands clinical understanding of actin-like proteins and their variations. By elucidating their structures and functions, researchers can gain insights into how these proteins contribute to cellular organization and behavior. The identification of BeeR as a distinct actin homolog with a unique structure has significant implications for the development of targeted therapies, providing structural insights that can help inform more innovative drug design.1
“At this time, we don’t know the function of BeeR,” adds Dr Bergeron. “Nonetheless, the identification of an actin-like protein forming a tubular structure transforms our understanding of the evolution of this critically important family of proteins.”2
