A Rare Coincidence of Science
Unlikely as it is, two Colby biology professors share a specialization in SUMO protein research
When Robert Augustine and Yee Mon Thu, both assistant professors of biology, were hired to teach at Colby, they were astounded to learn that they had something unusual in common: both study proteins that play a vital role in regulating gene expression and cellular processes like repairing DNA.
Their field, SUMO proteins, is a small one. Even at a large research university, it would be a big surprise to find two scientists working on the same protein. At a small liberal arts college like Colby, it’s almost unthinkable.
“The chances that two people would work on the same protein are incredibly low,” Augustine said.
What the coincidence has meant in practice is that Augustine, who studies mosses, and Thu, who studies yeast and human cancer cells, are enjoying an ethos of camaraderie, teamwork, and synergy in the Arey Life Sciences Building. Their students are, too.
“We can exchange techniques because there are some unique things that are very specific to SUMO,” Thu said. “There’s a very intimate knowledge that SUMO people have, and we have it.”
That’s exciting because the SUMO family of proteins, first discovered almost 30 years ago, is a critical cell modifier. As these proteins are better understood, they have the potential to help with the development of therapies for many diseases, including cancer. They may be instrumental in developing crops that can survive climate change.
“If we understand it, then we can come up with ingenious ways to modify either human cells or plant cells,” Thu said.
Learning about a cellular communication pathway
To understand SUMO proteins, it’s important to know some basics about cell biology. Cells, the basic building block of all living things, fall into one of two categories. There are prokaryotes—for example, single-celled bacteria—that do not have internal compartments such as a nucleus. And there are eukaryotes, which do have compartments.
Although those latter cells can be single-celled, they form animals, plants, fungi, and more complicated organisms, which have something special in common: complex networks of intracellular communication pathways.
“What we mean by this is that internally, cells communicate with each other. They need to [convey] when things are going wrong,” Thu said. “Almost every living thing has this system.”
Controlling the communication networks is where SUMO proteins come into play. SUMO stands for Small Ubiquitin-like MOdifier, and they attach to other proteins in a dynamic process called sumoylation. This way, they change how those proteins work. Think of them as a cellular stress response: they are signal flares that respond to heat shock, DNA damage, drought stress, cold stress, lack of oxygen, and other conditions and initiate a molecular repair process to fix the damage or protect against the stressors.
“Our cells are trying to maintain the status quo so that they don’t acquire so many mutations,” Thu said. “This communication system is part of the DNA damage response.”
A profound potential
Thu’s background is in cancer biology, and she is interested in finding ways to prevent the human genome—the complete set of DNA instructions located within the cell—from going haywire. She and her students use baker’s yeast as a model organism to study the SUMO pathway, and her lab is faintly but unmistakably redolent of fresh bread.
Augustine is a plant biologist who caught the gardening bug as a kid growing up in Brooklyn, N.Y. His family had a little backyard garden plot, which made a nice counterpoint to the concrete and asphalt backdrop of the city. “I grew plants with my dad and have been growing a garden ever since. It just never left me,” he said.
In his lab, he works with Physcomitrium patens, a type of spreading earth moss often utilized for studies on plant evolution and development.
“There’s the potential to have really profound impacts on making the next generation of crops that can survive under the climate change that we’re feeling right now,” he said.
In their labs, Augustine, Thu, and their student assistants are doing research that will add to the body of scientific knowledge and, hopefully, contribute to lasting societal change.
“I think a lot of students really want to get their hands dirty with molecular research,” Augustine said. “They could do it with yeast, or moss, or with a human cell line. Either way, they are going to get that experience they’re seeking.”
Among the mosses
Abby Stathis ’27 is a double major in English and biology. She wanted to do something interesting the summer after her first year, ideally incorporating hands-on research, and Augustine’s lab fit the bill.
“Moss sounds pretty cool. SUMO proteins also sound pretty cool,” she remembered thinking when she applied for the position.
Now, Stathis is working on a research project in which she’s trying to disable some of the enzymes that help SUMO proteins attach to target proteins in moss. She is doing that with the help of CRISPR, a bacterial immune system that scientists have adapted to use as a tool for gene editing.
“My end goal is to see how moss with these dysfunctional enzymes responds to heat stress, compared to moss with enzymes that are functional,” she said.
The process has been fascinating and clarifying in regards to figuring out her own next steps.
“I’ve always known that I’m pretty interested in biology, DNA, and genetics, but I didn’t know if I would enjoy being in a lab,” Stathis said. “I think a big part of learning how to work in a lab is making mistakes, and I do not like to make mistakes. I have to be OK with sometimes having to redo things, and I think I’ve realized that I can be OK with that. And so I think I definitely want to keep doing research.”
Celia Buetens ’26, a double major in studio art and biology, was busy moving moss colonies into their own space on a Petri dish. The mosses on the plate were special. A couple of weeks before, she had transformed them with Cas9, a protein that acts as molecular scissors, and CRISPRs that navigate the scissors to the correct DNA location for gene editing.
“As the moss grows, it’s going to grow into each other,” she explained. “I want to be able to analyze one colony specifically, and so I’m moving colonies into their own space on the plate so they don’t get mixed up.”
Buetens is angling to find a way to decrease the amount of SUMO in the mosses’ cells without totally eliminating the essential protein. She’s thrilled to learn that so far, at least, it looks like her process is working.
“I love working here,” she said of the lab. “This is a lot more extensive than a lab class, because you get a lot more time. You really get to see a beginning and an end, or at least a beginning and a middle, even if you don’t get to see the end. And then it’s cool to be editing DNA. Not a lot of people get to do that, and it’s cool that I’ve done it.”
Down the hall, with the yeasts
Nkechinye Baadi ’25, a biology major, feels the same way about her research. During her first year at Colby, she took biology classes that made her think the subject wasn’t for her. But when she took genetics with Thu, something clicked.
“I am so into science fiction, and so I’m interested in genetics,” Baadi said. “It’s a lot of gene editing, and I’ve always thought that was cool.”
The first independent project that Baadi worked on was “humanizing” yeast by replacing yeast genes that are part of the sumoylation process with human versions.
“I was taking the human version and putting it in yeast to see if the human version would be able to work well in yeast cells,” Baadi said.
It didn’t work, but that’s part of the scientific process, the student said. She was captivated by what she was doing in the lab, which felt like bringing science fiction to life. Baadi stayed as one of Thu’s lab assistants for multiple semesters and has worked on genetic modification projects like cloning, creating chimeric genes by combining portions of two or more genes to create a new gene, and more.
“In classes, you learn a lot about how it works, but then in the lab, you actually do it and see the results,” Baadi said. “I think that not a lot of people are privileged enough to actually be able to see or use those techniques that we use a lot. In cancer biology [class], we were talking about DNA repair mechanisms. I said, ‘Oh, I know this one because I use it all the time.’”
For Cheung “Samuel” Li ’25, a biology major who will be starting a doctoral program this fall at NYU Grossman School of Medicine, the opportunity to work in Thu’s lab means he got a head start on his interest area of cancer research. His senior thesis project uses yeast as a model to mimic the human cancer oncogene, or mutated genes that cause uncontrolled cell growth and division.
Li has appreciated the positive spirit, free of competition and drama, that he has found in the Biology Department, including its SUMO corner. In the summer of 2023, when he was working in Thu’s lab, he and her other assistants met every couple of weeks with Augustine’s assistants to share what they were doing and learning.
“It’s very cooperative,” he said, adding that he has loved doing hands-on research. “Even if the [projects] aren’t successful, they’re still very rewarding. You will get some sort of results, and they will make some kind of contribution in some way.”
For the professors, too, the research they do with their students is full of possibilities. “This field has an outsized impact,” Augustine said.
