Studying protein structure and cells’ complexity can lead to understanding human disorders of all kinds. Aaron Joiner has chosen this research route.
Dave Burbank
Dave Burbank

Joiner Collage_edit.jpg

“Our work in yeast is important because if we ever hope to understand the complexity of a human cell, we first need…to understand the simplified version of events in model organisms such as yeast.”
Beatrice Jin; Dave Burbank
Beatrice Jin; Dave Burbank


Joiner and five more graduate students in Chris Fromme’s lab study how certain proteins move between organelles or move from inside a cell to outside of it.
Dave Burbank
Dave Burbank


Joiner studies TRAPPIII, transport protein particle, using Lego to describe the research; “There is a base set of Lego—protein structures—and you add pieces to it.”
Dave Burbank
Dave Burbank


Balancing research with other areas of his life, Joiner is a graduate school ambassador, works on diversity initiatives, and is an avid cyclist with a goal of cycling around all of the Finger Lakes. “I’ve done three of them so far.”
Dave Burbank
Dave Burbank

Cell Traffic—Think Grand Central Station

by Molly Karr '18

Before Aaron Joiner arrived at Cornell as a graduate student studying biochemistry, molecular, and cell biology, he had taken several practice MCATs and decided against going to medical school and had spent six months doing research at the Smithsonian Tropical Research Institute in Panama City, Panama.

Joiner, who hails from Beloit, Wisconsin, studied biochemistry at Beloit College, a liberal arts school near his hometown. He had never given much thought about applying to graduate school until after shadowing several physicians. He then realized he wanted to pursue a different field.

“When I found out I would get tuition waived and get paid to pursue a PhD, I wanted to go for it,” says Joiner, who explains that he chose Cornell due to its excellent focus on careers, rotational program, financial offerings, and proximity to nature.

“I’m a very practical person. I wanted to go to a school with rotations so that I could sample different labs and research topics before deciding on what I liked. Another big factor for me was choosing a school that offered the most competitive financial care and centered on career exploration. The BEST (Broadening Experiences in Scientific Training) program here shows graduate students what careers are out there, other than being an academic professor,” explains Joiner.

Choosing a Lab to Study One Node, TRAPPIII, of the Cells’ Transportation System

At Cornell, students in Joiner’s program work in three different labs during their first year for 10 weeks each. By the end of the academic year, the students decide which lab suits their interests—personal and academic—best. Joiner, who is in his fourth year of graduate school, works in J. Christopher Fromme’s lab, Molecular Biology and Genetics/Weill Institute for Cell and Molecular Biology. He began in 2015.

“Our lab focuses on a set of proteins called guanine nucleotide exchange factors, which serve as one of the modes of regulation for vesicular trafficking events. These proteins function as a switch point, where they can help decide when and where to form and transport vesicles,” says Joiner, who specializes in a protein complex called TRAPPIII (transport protein particle).

Along with five other graduate students, Joiner studies how certain proteins or lipids are moved between organelles or from the inside to the outside of the cell. In all eukaryotic cells, this process occurs through vesicles—which are like a pouch full of proteins—that travel through the Golgi complex, affectionately referred to by the Fromme lab as the Grand Central Station of the cell.

First, Think Lego—Then, TRAPPIII Complex

For those who haven’t researched the intricate and complicated details of proteins, Joiner uses Lego as a helpful metaphor. “There is a base set of Lego—the protein structures—and you add pieces to it. We are trying to understand the base set; it would give us a lot of information for how it actually functions. Then, other labs can build off of it,” says Joiner, whose goal is to solve the atomic level structure of the TRAPPIII complex.

Joiner uses x-ray crystallography and more recently cryoelectron microscopy to study the atomic structure of proteins. He uses Saccharomyces cerevisiae (more commonly called Bakers’ yeast) as a model organism to understand how a cell is working. “Although we study the proteins in yeast, higher eukaryotes, such as dogs and humans, have them too. Our work in yeast is important because if we ever hope to understand the complexity of a human cell, we first need to be able to understand the simplified version of events in model organisms such as yeast,” says Joiner.

Why Understanding a Protein’s Structure Is Important

One of the most interesting aspects to Joiner’s research is that, until very recently, the TRAPPIII complex had only been thought to function in a pathway called autophagy (a process where a cell can create more nutrients by eating parts of itself). However, Joiner and a fellow collaborator in the lab found that the protein complex actually was involved in the secretory pathway as well.

Why is this work important? Joiner explains that understanding the structure of a protein directly corresponds to understanding how it actually functions. “There is so much information in the structure of a protein, and with it, you can make all sorts of mutations and direct its functions,” stresses Joiner.

“Knowing the structure of the engine helps you understand how the engine functions. Similarly, knowing the structure of a protein helps you understand how the protein functions.”

Take, for instance, a car. If you are told how the engine works, you might be able to understand the basic idea. However, if you are told how the engine works and shown exactly which pieces are doing what and how they are doing it, you will understand it much more clearly. “Knowing the structure of the engine helps you understand how the engine functions. Similarly, knowing the structure of a protein helps you understand how the protein functions,” explains Joiner.

A Day in the Lab with Joiner—What Makes It Interesting

No two days in the lab are exactly the same for Joiner. One morning, he could be trying to purify a protein to use it in a crystallization screen and by afternoon he might be manipulating the DNA sequence of a specific gene to make a mutation in it. The following day, he could be using fluorescence microscopy to identify the specific localization of a certain protein in a cell. “Because our lab uses a wide range of techniques to answer our scientific questions, the variation in what I have to do on a day-to-day basis makes the work really interesting,” says Joiner.

Besides the actual research, Joiner chose Fromme’s lab due to his mentorship style and encouragement of his student’s various passions. “Fromme isn’t going to count hours that I am in the lab, but rather he cares about how productive I am and what I am learning. I also wanted someone who would be supportive of my activities outside of the lab, who would want me to do those things. Chris is very encouraging of extracurricular activities, even getting on board with some of the diversity recruitment himself,” says Joiner.

Outside the Lab—Balancing Life as a PhD Student

“A lot of my time outside the lab is spent on diversity initiatives. I’m a graduate school ambassador. I am involved in trying to recruit the next generation of Cornellians and to make sure that the student body is more diverse. I also volunteer for the Upward Bound program, which helps underserved high school students prepare for college. It’s a program that is near and dear to my heart. I was a part of it in high school,” says Joiner, who has also founded a shadowing program for participants in Cornell’s STEP program (another college preparatory program for high school students) to show younger students what it’s really like to work in a lab and to encourage them to pursue higher education.

With all of the complex, stimulating research Joiner has worked on in the Fromme lab these past two years, it has been the mentorship that has been the most rewarding experience. “That’s a really fulfilling thing for me—to use my research as a tool to guide and recruit younger students,” explains Joiner.

One of the most difficult aspects of Joiner’s graduate experience at Cornell did not tie to his research, but rather dealt with a perceived lack of belonging. “My first year was a tough transition. On top of adjusting back to an academic lifestyle, I noticed that I was the only person of color in my classes. After this realization, I began to struggle with imposter syndrome, which is the idea that you feel like you don’t necessarily belong or deserve to be at the place you’re at,” says Joiner.

It took some time for Joiner to realize his worth and that he did truly belong as a graduate student at Cornell. Making sure he balanced his research with the other activities he enjoyed in life helped to ease the transition process and establish a healthy work-life balance.

In addition to working with the diversity initiatives at Cornell, Joiner is an enthusiastic runner and cyclist, and he loves basketball. “I have found that you can be very happy while getting your PhD, as long as you make time for yourself. For me, I go outside and run the trails near campus. One of my personal goals is to cycle around all of the Finger Lakes, and I’ve done three of them so far,” says Joiner.

According to Joiner, one of the key elements of mental and academic success as a graduate student is to be upfront about what you really enjoy doing and plan how you go about obtaining your goals.

“If you’re honest with yourself in terms of what you would need adviserwise, researchwise, resourcewise, and healthwise in order to be successful, and you make a conscience effort to get those things, you can have a great time. No matter where you go for graduate school, the first semester is always rough, but I think that if overall, you’re not happy while you’re working toward your PhD, then you’re not doing it right,” says Joiner.