Jess Translating Science

Type of article: Profile story

Reading time: 5 minutes

Jessica Desamero, PhD

Growing up, one of Devon Semoy’s pastimes was watching shows on the Discovery Channel and Animal Planet. One memorable nature documentary was Wild Discovery, which showcased a wide range of animals from around the world. From this, he became fascinated with how nature works.

For his undergraduate studies, Semoy attended the University of the West Indies, Mona in Jamaica. Here, he took classes like physical chemistry and molecular biology. He also continued to watch documentaries like Cosmos: A Space Time Odyssey, hosted by renowned astrophysicist Neil DeGrasse Tyson. These classes and documentaries cemented his fascination with science.

By the end of college, Semoy became interested in discovering the world of research. After speaking to various people about graduate school, he decided to pursue a PhD in the United States.

Bacterial DNA Replication and Repair

Semoy received a PhD in Biochemistry from the City University of New York (CUNY) Graduate Center. He worked in the lab of Dr. David Jerulzami, and his PhD research involved the biochemical, biophysical, and structural characterization of proteins involved in DNA replication and repair.

One of Semoy’s PhD research projects involved DNA replication of a chromosome in Vibrio cholerae bacteria, the bacteria that causes cholera. “These bacteria have two chromosomes (belonging to the 10% of bacteria that have their genome split across multiple chromosomes)…It was already known that the main chromosome, chromosome 1, follows the typical mechanism for replication. But it was still somewhat mysterious how the secondary chromosome replicated,” he said.

Chromosome 2 seemed to have its own replicator or initiator protein that started replication. Therefore, Semoy’s project aimed to figure out how this protein exactly interacts with DNA and how the replication complex forms. His structural work was unsuccessful, but his biochemical work was insightful. “We figured out that the initiator protein likes specific sequences on the DNA and that it exists in a monomer-dimer equilibrium, with the monomeric form being competent for DNA binding. We have preliminary evidence that the initiator origin DNA complex forms a higher order protein-DNA complex that could trigger replication,” he said. 

During Semoy’s fifth year of graduate school, he was determined to gain experience in structural biology. Therefore, he also took on a previous graduate student’s project about DNA repair in bacteria. In this project, Semoy used cryogenic electron microscopy (cryo-EM) to freeze biomolecules and determine their 3D shapes at a molecular resolution. “It became a very fruitful endeavor,” Semoy said.

This project particularly focused on proteins involved in nucleotide excision repair (NER). Most other DNA repair pathways are specific for one type of damage, while others target specific base modifications, but NER can recognize a large variety of DNA lesions. “We found that question to be very interesting. How can one protein recognize such a large plethora of damages?” he said. “It doesn’t make sense for this to be a purely chemical recognition (bonding interaction and geometry) process. It must be figuring out some kind of intrinsic feature of DNA.”

From his structural work in this project, he uncovered how. “It turns out to be a very interesting mechanism where it’s distorting the DNA to discern native from damaged DNA, and it seems to go through a very complicated series of steps to do so,” he said. Semoy presented this research at two science communication events at CUNY.

Protein Tyrosine Phosphatases and Their Role in Diseases

Currently, Semoy is a postdoctoral fellow at Columbia University in New York. He works in the lab of Dr. Neel Shah, whose research focuses on protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). PTKs are enzymes that add phosphate groups from tyrosine residues on proteins, while PTPs remove phosphate groups. Both play a role in cell signaling in eukaryotes.

Semoy mainly works with the phosphatase SHP2. “It’s a pretty important protein that’s found in many different cancers…such as acute myeloid leukemia and other blood cancers,” he said. His research aims to characterize SHP2 using biochemical, biophysical, and structural techniques.

Post-translational modifications (PTMs) also play a role in several forms of cancer. Thus, Semoy aims to characterize PTMs on SHP2 as well. “I’ve been trying to develop a stable version of this PTM where it can be installed on a protein. And once it’s stable and specifically installed on the protein, we can really study what the effect of the PTM is,” he said.

The Value of Research

Overall, Semoy loves research for its novelty and problem-based nature. He is also generally interested in learning about how proteins function. Lastly, he believes basic science holds great value in understanding diseases. “If we have a good foundation for basic science, we can really come up with cures or other biomedical applications,” he said. “Knowing that you’re contributing to that very foundational sense for understanding diseases also is a form of inspiration.”

In the future, Semoy hopes to continue with research, either in academia or industry. He also encourages others to do the same. “When you go for a job in research, you can pick which aspects of research are exciting to you. And then you can really shape what your research project will turn out into,” he said. “The ability to just answer your own questions and pursue your own interests, I think that’s a really good thing.”

Even with the age of AI, researchers will still be indispensable. “There’s something really unique about doing research in the sense that it requires some love, some creativity, and intuition.”

Dr. Devon Semoy was interviewed for this article.

The headshot was provided by the interviewee.