Dr. Xiaofan Li, a newly minted PhD, recently graduated from the Molecular, Cellular and Integrative Biosciences (MCIBS) program. Xiaofan did her dissertation work in the lab of Dr. Tim Jegla a molecular neuroscientist. Xiaofan got her BSc in Applied Biology, with a minor in Geography, from Hong Kong Baptist University. Recently, we caught up with Xiaofan to learn about her thesis research, and future plans.
Xiaofan’s research focuses on voltage-gated potassium (K+) channels. These channels are tetrameric transmembrane proteins, and pass K+ ions in and out of the cell. These ion channels are found in the brain, and heart, among other organs, and regulate electrical signaling. Xiaofan’s first project was to determine when during the evolution of the nervous system, the voltage-gated K+ channel evolved. Specifically, if it evolved before or after the first appearance of neurons. To study this, Xiaofan used two organisms, ctenophores (comb jellies) and cnidarians (sea anemone, jellyfish). She has discovered that the 8 families of voltage-gated K+ channels were already defined in the common ancestor of parahoxozoans, which include cnidarians (see diagram), and family-specific features of channel functions were also in place. Ctenophores differ from parahoxozoans in that their channels do not fall into one of the 8 subgroup families of voltage-gated K+ channels. Ctenophore channel sequences still possess homologous features to two of the three superfamilies of parahoxozan genes, which indicates that the divergence of ctenophores happened during the diversification of prototypical voltage-gated K+ channels, but before the channels we are familiar with were established.
Another project Xiaofan worked on is looking at phosphoinositide modulation of an EAG (ether-a-go-go) family voltage-gated K+ channel. Phosphoinositides are a group of low-abundance phospholipids found on eukaryotic membranes. These phospholipids can interact with proteins to modulate their activity, or localize them to specific membrane compartments. Specifically, Xiaofan looks at the effect phosphoinositide PIP2 has on EAG family channels. Previously, PIP2 has been shown to affect voltage-gated K+ currents and alter neuronal excitability, but they have not been tested on EAG family channels yet. Xiaofan discovered that phosphoinositides modulate the Elk1 channel, by inhibiting voltage activation and stabilizing the open state channel after voltage activation. Both of these modifications lead to an attenuated change in channel activity in response to voltage variation. This acts as a buffer to further change in transmembrane voltage. You can ready more about both of these projects here.
In the future, Xiaofan plans to go into academia to research and teach. She hopes to conduct research on how the brain works, and how scientists can use that knowledge to understand and predict human behavior. When not in the lab, Xiaofan enjoys playing the piano and ice skating.
Advice for new graduate students?
To be successful in graduate school, Xiaofan suggests that grad students spend time thinking and planning about what they really want to achieve, in both the long and short term. Additionally, students should be proactive and communicate with their adviser regularly, find opportunities to practice writing and presentation skills, and keep learning new things in your field that interest you. Learn from colleagues, seminars, and conferences. It is also important to relax and have fun as well. Grad school is a long journey, and you do not want to die of stress midway!