ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Rahul Baroi is first author on ‘ Mitochondrial phosphatase PPTC7 promotes EGFR recycling by facilitating VPS4A endosomal localization’, published in JCS. Rahul is a PhD student in the lab of Dr SubbaReddy Maddika at the BRIC Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India, investigating how extra-mitochondrial activity of PPTC7 regulates cargo trafficking.
Rahul Baroi
How would you explain the main findings of your paper in lay terms?
When we travel in a city, quite often we get stuck in the traffic. To maintain a proper traffic system, we frequently employ traffic-controlling police to operate it. The cellular endosomal trafficking system is also like a busy city, with many biochemical events going on at a particular time. Enzymes (such as kinases and phosphatases) can act as a kind of traffic police. Often, some extracellular ligand molecules will bind to their receptor on the cell surface and travel to a destination within the cell. Sometimes they travel to the lysosome and get degraded, whereas other receptors travel back to the membrane through a process called receptor recycling. In our study, we have found that a phosphatase named PPTC7, which dephosphorylates a trafficking-related protein called vacuolar protein sorting-associated protein 4A (VPS4A), makes sure that VPS4A will be appointed to act at the early endosome to perform its responsibility of controlling receptor traffic.
Were there any specific challenges associated with this project? If so, how did you overcome them?
One of the most important challenges was to identify the substrate for PPTC7. We tested different substrates one by one and found VPS4A to be the potential substrate. Identifying the dephosphorylation sites on VPS4A was also challenging, as we have identified a new site that was not mentioned in the available databases (such as PhosphoSitePlus). We took a mass spectrometry-based approach to identify various phosphorylation sites on VPS4A.
When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?
We always celebrated when an experiment worked well for us. Confirming the substrate and identifying the phosphorylation site were the key moments for me for this project. We tested various substrates and sites, and we initially suspected other proteins to be the substrate, but when we confirmed that VPS4A is dephosphorylated by PPTC7 at serine residue 335, it was a turning point for this project. Now, I can call it a ‘eureka' moment.
Why did you choose the Journal of Cell Science for your paper?
JCS is one of the most renowned journals that deals with wider aspects of cell biology. We have identified a new phosphorylation site on VPS4A that is involved in its regulation, discovering an extra-mitochondrial function of a protein that was only known to have mitochondrial substrates until now. We feel that publishing in JCS will enable this story to reach various research groups in the field of cell signaling and vesicular trafficking.
Have you had any significant mentors who have helped you beyond supervision in the lab? How was their guidance special?
My supervisor Dr SubbaReddy Maddika has played an important role in shaping my academic career. His mentorship has always driven me to think out of the box and work outside my comfort zone. In addition to mentorship, he has provided encouragement for extra-curricular activities, endless support for science, the freedom to perform experiments, scientific discussions and lab presentations, which have helped a lot to sharpen my career.
What motivated you to pursue a career in science, and what have been the most interesting moments on the path that led you to where you are now?
I graduated from Presidency University, Kolkata, India, and had a mostly research-driven curriculum. My first lab exposure happened when I applied for a 2 month internship program at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India, in a Drosophila evolutionary biology lab. I also later had research experiences at the Saha Institute of Nuclear Physics, Kolkata, India, in the metabolomics lab and at Presidency University in the yeast genetics lab. All these exposures helped me to be motivated to pursue research. During my MSc degree, cell biology and genetics were my favorite topics. The way those curricula were designed helped me to generate a quest for science and choose my current lab at the Centre for DNA Fingerprinting and Diagnostics.
Who are your role models in science? Why?
Every research field has its impact, be it basic science or translational research. My role model is Acharya Jagadish Chandra Bose (Assistant Professor of Physics, Presidency College) who made a significant contribution in the field of plant physiology. He carried out his research at Presidency College (now Presidency University, Kolkata). Despite having technological issues and limited resources, he made a great impact in the field of plant physiology.
What's next for you?
I want to remain in science as an administrator, so I am planning accordingly.
Tell us something interesting about yourself that wouldn't be on your CV
Other than doing science, I like to cook and play badminton, and I also have some interest in Indian music.
Rahul Baroi's contact details: BRIC Centre for DNA Fingerprinting and Diagnostics, Inner Ring Road, Uppal, Hyderabad 5000039, Telangana, India.
E-mail: [email protected], [email protected]
