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Alumni Profile: John Sakon

John Sakon at a Neural Science Lab at New York University

John received his doctorate in physics from North Carolina State University in November, 2010 under the supervision of Prof. Keith Weninger. His dissertation was entitled "Detecting the conformation of individual proteins in live cells using single molecule fluorescence resonance energy transfer." He is currently a postdoctoral fellow in the Center for Neural Science at New York University where he does cognitive neuroscience research on memory in nonhuman primates.

How did you end up pursuing your degree in physics at NC State?
I did my first research in an NSF Research Experience for Undergraduates summer program through the Center for Space and Planetary Sciences at Oklahoma State University. I was never in love with physics from a classroom perspective but I really enjoyed my first taste of research. I ended up going back for a second summer to continue my work and even got a publication out of it. This, combined with senior research I did at the College of William and Mary, made me think that pursuing a career in science research would be fulfilling. Fortunately, I was able to come to NC State and join Keith's lab almost right away and start working on new projects.

Can you explain your PhD thesis?
As far as I know, the technique we developed made me the first person to watch a single protein fold in a live cell. We used a technique called single molecule FRET, where we strategically attached fluorescent dyes to a protein that would give off a differential signal depending on whether it was in its folded or unstructured state. The major hurdle was achieving enough signal to noise to image these single dyes within the optically noisy environment of a live cell. In the end, we were able to not only tell that individual proteins we microinjected into cells were folding (and therefore incorporating themselves into the cellular machinery), but because we were imaging single molecules we were able to track them diffusing throughout the cell and measure how long they stayed in their folded state. This kind of information is generally known as protein dynamics, and is starting to unlock how our cellular machinery is able to achieve the myriad molecular functions in our body. And, unlike previous work, achieving this in a live cell was an important step because proteins typically won't act the same outside of their native environment, as dozens of accessory proteins and other molecules influence their function in vivo.

What did the physics department offer that helped your research career?
For one thing, it was important for me to start doing research right away. I TAed for a semester, which was a good learning experience, but for me my motivation in graduate school was doing science. And I don't think I was unique in the department in starting research early on. I also liked the class structure where we were allowed to take 4 of our 10 classes outside of the department. While I still received a core physics background, the biochemistry and neuroscience courses I took had a big influence on my future career.

What about NC State in general [helped your research career]?
There is tons of research at NCSU and throughout the region. I mean for my first project I worked with Robert Nemanich's lab on a biophysics question that turned into a material science finding that we were able to publish. A lot of the research for that project involved the creation of nanocrystalline diamond films at Centennial Campus and doing radiation experiments in Dennis Brown's lab in NCSU biochemistry (where I also learned a lot of my cell culture techniques involved in my thesis). Later in my graduate career I developed an interest in neuroscience and was able to contribute to a project with George Augustine's [neurobiology] lab at Duke. They would purify synaptic vesicles and proteins for me to test on our microscope and I could just pick them up, throw them on ice and drive them back over to Raleigh in like 30 minutes. Ha.

Speaking of neuroscience, how did a physicist get interested in that topic in the first place?
I mean ever since my first research in my REU program—which was in a microbiology lab—I developed an interest in biological research. I knew right away when I came to NCSU that I wanted to do biophysics and Keith's lab had some really interesting projects. The proteins I studied were heavily involved in the brain and when I started to learn the field I became interested in how our molecular machinery influenced our everyday lives. I began reading about some fascinating work by Joe LeDoux (who's actually in my current department) and Eric Kandel and by the end of my graduate career I was reading nothing but papers about memory and neuroscience in general. From there I started seriously considering moving into the field. In particular, I wanted to move from the microscale to the macroscale and start studying something in our everyday lives. Memory research is really interesting in this way.

How did your background in physics help your new research career in neuroscience?
In all kinds of ways. As you hear from anyone physicists have a great background for success in any field. Figuring out how to solve an advanced physics problem is hard and requires a lot of perseverance. That obviously carries over to research, as the kind of person that finds a way to make things work in their physics studies is not going to give up so easily when the research isn't working. While I'm not doing molecular neurobiology-I could have stepped into a microscopy lab without missing a beat—there were definitely some skills that still carried over. In particular, learning to program in Matlab became a big part of analyzing my thesis data, and I've come to find it's one of the most important skills there is for analysis in electrophysiology. Also, frankly, I should mention that any time I tell someone my PhD is in physics there's this instant respect for my background despite the fact it wasn't in neuroscience. In fact, I meet former physicists in neuroscience all the time and they seem to be overwhelmingly successful.