Meet Dr. Jean-Ju Chung

Written by Dr. Zhibing Zhang (SSR’s Diversity Committee) in celebration of AAPI Heritage Month

Dr. Jean-Ju Chung

The Asian American and Pacific Islander (AAPI) Heritage Month is annually celebrated in the United States during the month of May. This commemoration recognizes the contributions and influence of Asian Americans and Pacific Islander Americans to the history, culture, and achievements of the United States. In celebration of AAPI Heritage Month, Dr. Zhibing Zhang (SSR’s Diversity committee) sat down with Dr. Jean-Ju Chung from Yale School of Medicine to learn about her work, career, and thoughts on the challenges she faced during the pandemic. Dr. Jean-Ju Chung is an Associate Professor of Cellular and Molecular Physiology at Yale School of Medicine. She currently leads a research lab focusing on uncovering the role of ion channels in reproductive physiology.

My research program triangulates the following: mechanistically deep understanding of cellular signaling in mammalian fertilization, male infertility,  and translational application of this knowledge to develop new approaches for male infertility treatment and innovative contraceptives. My laboratory seeks to understand cellular signaling via ion channels and transporters in sperm capacitation and fertilization. My early work explored the composition and function of the primary sperm calcium channel, CatSper, which is essential for hyperactivated motility and male fertility in mammals.

We discovered the CatSper channel is a multi-protein complex that organizes linearly arranged Ca2+ signaling nanodomains. Furthermore, we demonstrated that the molecular change and spatial arrangement of the CatSper nanodomains reflect motility and fertility of sperm cells. We are investigating channel assembly, trafficking, and activity modulation using a multi-disciplinary approach, including human and mouse genetics, comparative genomics and proteomics, biochemistry, electrophysiology, and advanced imaging. Based on the accumulated knowledge, we are currently expanding our research to develop CatSper modulators. My laboratory also investigates genetic basis of human male infertility and the underlying molecular mechanisms. Male infertility accounts for approximately half the cases of human infertility; half of these cases have no known cause and are projected to have a genetic basis. We have identified novel human variants associated with male infertility and studied the underlying molecular mechanisms, broadening the spectrum of sperm phenotypes and providing valuable insights into key mediators of human sperm development and male infertility pathogenesis.

1. What is your current position, and what does it entail?

Associated Professor in the Department of Cellular & Molecular Physiology at Yale School of Medicine.

2. Can you talk a little bit about yourself, where are you from? What first attracted you to the world of science? And how did you get to be in your current position?

I was born in Boston, USA (left when I was two and half) and grew up in Seoul, South Korea. So I would say I am made in USA but still from Korea as my identity is Korean. The beginning of my journey into science was quite simple and childlike. Watching Jane Goodall and her fascinating work with Chimpanzees on the National Geographic Channel was the first thing that attracted me to science as a child, and I wanted to study animal behavior. Live demonstrations in science class were rare in Korea at that time, so when I happened to see the breathing demonstration with freshly cut lungs from a lamb by chance during my visit to the Boston Museum of Science during my school vacation between elementary and middle school – my first time to get to see the model of the DNA double helix and the whole process from fertilization to birth as well! – was an eye-opener and still remains a vivid memory. I think it was around this time that I decided to become a ‘biologist’ and insisted on majoring in Molecular Biology instead of going to medical school, which was supposed to be decided by high school graduation in Korea. I loved my lab experience during my undergraduate and master’s studies, but felt that the cultural norm and environment was not really encouraging for female students to pursue academic careers, as the number shows: there was only 1 female faculty out of a total of 50 biology-related faculty members at Seoul National University at that time. So I decided to do my Ph.D. abroad, and I kind of came back to the U.S. My interest moved from organisms to organs to cells and molecules and how they work, especially ion channels and membrane receptors and how they signal. When I came across the sperm calcium channel, CatSper, in David E. Clapham’s lab, I kind of felt that I had turned around to come to the junction of my two interests – reproduction and signaling – because I studied GnRH hormone and retinoid action in neuroendocrinology as a master’s student, and here I am.

3. What impact has the pandemic had on your daily activities and your research?

Now I start my day with a pretty good coffee and end my day with a massage at home, because I ended up buying an espresso machine and massage chair for the long hours in front of the computer during pandemic shutdown. Like many labs in other institutions, my lab shut down for three months in year 2020. The shutdown and the slow recovery of bench time after reopening has two extreme impacts on my postdocs – the increased reading and thinking time for a senior postdoc was a blast in his manuscript writing. The loss of momentum in the initial learning curve and socialization of two other junior postdocs who just joined 3-4 months before the shutdown was not really positive – one left academia and joined industry during the shutdown and the other would attend an in-person conference for the first time this summer. I have been still doing bench work myself although to somewhat decreasing levels before pandemic, now I rarely find my time on bench.

4. Have you gained any valuable lessons from life during the pandemic?

A lot of soul searching: how fragile we are in the face of nature and how powerful science is to protect us. How precious the freedom of travel and interact with others is to our personal and scientific lives. How pervasive systemic bias, inequities and injustice are in society and how we as an individual, as a lab, as an institution can recognize and make an effort to improve them.

5. What are you most excited to do over the next year?

I’m excited that I would have more time to myself, to do research, and travel in a year or two as both of my kids go to college by then!

6. What words of inspiration would you like to share with the future generation of scientists?

But, he thought, I keep them with precision.
Only I have no luck any more.
But who knows? Maybe today. Every day is a new day.
It is better to be lucky. But I would rather be exact.
Then when luck comes you are ready.

7. Are there ways in which you think your heritage has affected your perspective or career trajectory?

Certainly, the innate Korean passion for education and the determination to maintain our culture and language throughout our long history and through many crises would be the foundation of my perseverance for all those long years and hours of training during my PhD and postdoctoral years. Being a Korean woman faculty in the sciences (especially in a US elite institution as a non-native speaker) has certainly been a lonely and marginalized experience that has made me more mature and understanding of people from diverse backgrounds. It has also been a rewarding experience because I know – whether I want to or not – that there are many (female) students who look up to me and see my presence and position as a signal of possibility, and I understand the meaning and weight of that.

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