Exploring a protein’s turf with TIRF

Investigating Otoferlin

Otoferlin is a protein required for hearing. Mutations in its gene sequence have been linked to hereditary deafness, affecting 360 million people globally, including 32 million children. Recently graduated PhD candidate Nicole Hams has spent the last few years working to characterize the activity of Otoferlin using TIRF microscopy. There are approximately 20,000 protein-coding genes in humans, and many of these proteins are integral to processes occurring in cells at all times. Proteins are encoded by genes, which are comprised of DNA; when mutations in the gene sequence occur, diseases can arise. Mutations in DNA that give rise to disease are the focus of critical biomedical research. “If DNA is the frame of the car, proteins are the engine,” explains Nicole. Studying proteins can provide insight into how diseases begin and progress, with the strategic design of therapies to treat disease founded on our understanding of protein structure and function.

Studying proteins

Proteins are difficult to study because they’re so small: at an average size of ~2 nanometers (0.000000002 meters!), specific tools are required for visualization. Enter TIRF. Total Internal Reflection Fluorescence is a form of microscopy enabling scientists like Nicole to observe proteins tagged with a fluorescent marker. One reason TIRF is so useful is that it permits visualization of samples at the single molecule level. Fluorescently-tagged proteins light up as bright dots against a dark background, indicating that you have your protein.

Another reason why proteins are hard to study is that in many cases, parts of the protein are not soluble in water (especially if part of the protein is embedded in the fatty cell membrane). Trying to purify protein out of a membrane is extremely challenging. Often, it’s more feasible for scientists to study smaller, soluble fragments of the larger protein. Targeted studies using truncated, soluble portions of protein offer valuable information about protein function, but they don’t tell the whole story. “Working with a portion of the protein gives great insight into binding or interaction partners, but some information about the function of the whole protein is lost when you study fragments.” By studying the whole protein, Nicole explains, “we can offer insight into mechanisms that lead to deafness as a result of mutations.”

Challenges and rewards of research

Nicole cites being the first person in her lab to pursue single molecule studies as a meaningful achievement in her graduate career. She became immersed in tinkering with the new TIRF instrument, learning from the ground up how to develop new experiments. Working with cells containing Otoferlin, in a process known as tissue culture, required Nicole to be in lab at unusual hours, often for long periods of time, to make sure that the cells wouldn’t die. “The cells do not wait on you,” she explains, adding, “even if they’re ready at 3am.” Sometimes Nicole worked nights in order to get time on the TIRF. “If you love it, it’s not a sacrifice.”

Why grad school?

As an undergraduate student studying Agricultural Biochemistry at the University of Missouri, Nicole worked in a soybean lab investigating nitrogen fixation, and knew she wanted to pursue research further. She had worked in a lab work since high school, but didn’t realize it was a path she could pursue, instead convinced that she wanted to go to medical school. Nicole’s mom encouraged her to pursue research, because she knew that it was something she enjoyed, and her undergraduate advisor (who completed his post-doc at OSU) suggested that she apply to OSU. She feels lucky to have found an advisor like Colin Johnson, and stresses the importance of finding a mentor who is personally vested in their graduate student’s success.

Besides lab work…

In addition to research, Nicole has been actively involved in outreach to the community, serving as Educational Chair of the local NAACP Chapter. Following completion of her PhD, Nicole intends to continue giving back to the community, by establishing a scholarship program for underrepresented students. Nicole remembers a time when she was told and believed that she wasn’t good enough, and while she was able to overcome this discouraging dialogue, she has observed that many students do not find the necessary support to pursue higher education. Her goal is to reach students who don’t realize they have potential, and provide them with resources for success.

Tune in on December 3rd  at 7pm to 88.7 KBVR Corvallis or stream the show live right here to hear more about Nicole’s journey through graduate school!

Thanks for reading!

Full Interview Here

Earlier in the show we discussed current events, specifically how the tax bill moving through the House and Senate impact students. Please see our references and sources for more information.

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