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. Anuttoma Ray is first author on ‘ Regulated dynamic subcellular GLUT4 localization revealed by proximal proteome mapping in human muscle cells’, published in JCS. Anuttoma conducted the research described in this article while a Postdoctoral researcher in Dr Timothy McGraw's lab at Department of Biochemistry, Weill Cornell Medicine, Cornell University, New York, USA. She is now an Editor at Cactus Communications, Princeton, NJ, USA, where she leverages her skills and expertise for the scientific community to drive the creation of high-quality, research-based manuscripts for academic publishing.

Anuttoma Ray

How would you explain the main findings of your paper in lay terms?

Type 2 diabetes is a chronic metabolic disorder characterized by persistent high glucose levels in the blood and is caused by resistance to insulin. Under normal conditions, after a meal, the blood glucose level in our body increases, which stimulates the secretion of the hormone insulin. Insulin then stimulates uptake of glucose into fat and muscle cells to lower blood glucose levels through regulation of the insulin-responsive glucose transporter protein GLUT4. Regulation of glucose transport is thus determined by the amount of GLUT4 at the plasma membrane (surface) of the cells as well as its translocation to the surface of fat and muscle cells from intracellular compartments. Interestingly, GLUT4 redistribution to the plasma membrane is impaired upon insulin resistance and in type 2 diabetes. Apart from insulin, exercise also stimulates glucose uptake in skeletal muscle via contraction, and this uptake is also dependent upon translocation of GLUT4 to the plasma membrane. Exercise stimulates an enzyme, AMPK, in muscle cells which drives GLUT4 translocation and glucose uptake. The molecular and mechanistic overlaps between insulin-stimulated and contraction-stimulated signaling inputs to GLUT4 are not well understood. In this study, we aimed to explore the underlying molecular mechanisms downstream of insulin and AMPK signaling in human muscle cells.

Our results show that AMPK promotes redistribution of GLUT4 to the plasma membrane by regulating the molecular mechanisms of exocytosis and endocytosis. Additionally, using advanced techniques, we created a high-resolution whole-cell protein map of GLUT4 localization. This allowed us to visualize the GLUT4 trafficking itinerary in human skeletal muscle cells and see how that itinerary is altered by AMPK signaling.

This GLUT4 protein atlas will thus provide us with the structural framework for future studies of molecular mechanisms controlling GLUT4 trafficking. These new insights, which show that regulation of GLUT4 translocation leads to increased glucose uptake in response to AMPK signaling, should facilitate the discovery of modulators that will help us to therapeutically target and treat Type 2 diabetes.

Were there any specific challenges associated with this project? If so, how did you overcome them?

For this project, we worked with a human muscle cell line, which previously had never been used in our lab. As a result, we were totally unaware of how these cells would behave under different conditions and treatments. Thus, a lot of trials and standardizations for optimization of experimental conditions were required to get meaningful results.

Moreover, a year into the project, the COVID-19 pandemic struck. Lockdowns and restrictions to laboratory access posed a substantial challenge in maintaining the continuity of the workflow and cell culture work, which was imperative for this project. Additionally, this was a highly mentally challenging phase for me due to a personal loss in the family. Nevertheless, I chose to focus on my project as much as possible in an attempt to overcome these obstacles.

When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?

During this study, we had some interesting developments at various stages of our research that kept us enthusiastic and motivated. One such instance was when we discovered that AMPK regulation of GLUT4 in human muscle cells occurs via regulation of both inhibition of GLUT4 endocytosis and acceleration of GLUT4 exocytosis. Previous studies have shown that, in rat muscle cells, AMPK increases GLUT4 plasma membrane expression by inhibiting endocytosis only, whereas in fat cells, insulin increases GLUT4 plasma membrane expression by increasing exocytosis. Moreover, our current study also showed that in these muscle cells, insulin-induced signaling only increased exocytosis. Thus, our observation of a dual effect of AMPK regulation on GLUT4 trafficking was very unique, and it greatly motivated us to explore this model system further.

Why did you choose Journal of Cell Science for your paper?

Journal of Cell Science is an internationally renowned peer-reviewed journal that is known to publish cutting-edge research articles with impactful findings in the field of cell biology. We chose Journal of Cell Science for our paper as we believed it to be the ideal platform for disseminating the novel findings of our study among its wide and diverse scientific audience.

Airyscan high-resolution microscopy image showing immunofluorescence co-colocalization (white arrows) of HA-GLUT4-GFP with the Golgi marker, GOLGA4, in a day 3-differentiated SKM cell (binucleated). Scale bar: 20 µm.

Airyscan high-resolution microscopy image showing immunofluorescence co-colocalization (white arrows) of HA-GLUT4-GFP with the Golgi marker, GOLGA4, in a day 3-differentiated SKM cell (binucleated). Scale bar: 20 µm.

Have you had any significant mentors who have helped you beyond supervision in the lab? How was their guidance special?

I would like to mention my PhD mentor, the late Dr Parmender Mehta. He played an instrumental role in shaping and guiding my scientific career. He helped me to hone my scientific thinking and writing skills, always motivating me to stay positive. I also want to thank my postdoctoral mentor, Dr Tim McGraw. His enthusiasm for science and unparalleled expertise in diverse areas of biology is really admirable. Both my mentors have instilled in me a desire to pursue science for the love of knowledge and truth and not necessarily for the rewards, which I believe is truly wonderful.

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?

Ever since my school days, when I was first introduced to science, I have always felt an inner attraction towards it. Science evokes a curiosity and excitement in me which no other subjects do. Biology especially fascinated me. The term ‘cloning’ awed me from the moment I learned of it, through the cloning of ‘Dolly the sheep’, which was a worldwide phenomenon at that time. This inspired me so much that I did my Master's thesis project on cloning of microRNAs. My education introduced me to the fascinating world of the biosciences and I learned that bioscience is a discipline that has the potential to benefit the entire community at large. The next big step of my scientific career came when I decided to pursue my PhD in the USA in biochemistry and molecular biology. My doctoral thesis work focused on investigating the molecular mechanisms that regulate the trafficking and assembly of connexins into gap junctions in the pathogenesis of pancreatic and prostate cancer. My PhD training introduced me to the diverse field of bioscience and the intricacies of academic research. There seemed to be no end to the process of acquiring knowledge when I realized the vastness of what we are yet to learn and discover. The next pivotal stage in my career was acquiring a postdoctoral position at Cornell University, where I got an opportunity to work on a project on diabetes, which led to this publication. Moreover, getting to work on this project in close collaboration with Pfizer was an added motivation for me. This position allowed me to hone my overall scientific skills and aptitude in the best possible way.

What's next for you?

I've recently transitioned out of academia as I am enthusiastic about exploring newer career avenues that align with my education and overall experience. After my postdoctoral career, I have decided to move into the field of scientific communication and publications, where I look forward to applying my acquired skills in various ways, taking on new challenges, and interacting with diverse science professionals, while continuing to contribute to the scientific community.

Tell us something interesting about yourself that wouldn't be on your CV

Had I not gone into academia, I would definitely have become an athlete. I take keen interests in various sports, and participated in various tournaments during my school, college and university days, even through my PhD. When not at work, I love travelling and exploring new places with my husband. I am also a hard-core animal lover, and I always do my bit to make their lives better.

What changes can improve the professional lives of early-career scientists?

Availability of adequate funding in the form of start-up grants can significantly improve the professional lives of early-career scientists. In this way, they can focus more on their research instead of always worrying about acquiring funds.

Anuttoma Ray's contact details: Cactus Communications Inc., Princeton, NJ, USA.

E-mail: anuttomaray@gmail.com

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et al. 
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2023
).
Regulated dynamic subcellular GLUT4 localization revealed by proximal proteome mapping in human muscle cells
.
J. Cell Sci.
136
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jcs261454
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