Q & A - Leonora Martinez-Nunez
What sparked your interest in the life sciences?
I grew up in Mexico in the ‘90s, and I remember watching the news, and the host was talking about a spreading virus that was affecting the population. He spoke about HIV, and I thought, maybe I can discover a cure if I study chemistry or something like this. I was always interested in something scientific or naturerelated, dinosaurs, dolphins, bugs, or chromosomes. So I studied biology in the local state university and started a journey to become a scientist. Then I went to grad school, where I got a master’s and PhD in Life Sciences with an emphasis in Microbiology.
My interest in finding the cure to HIV changed within the years, and I ended up studying filamentous fungi. How they grow, and all about their cells. After that, I moved from Mexico to the USA, where I got a postdoctoral position to study molecular machines vital cells. Nowadays, I explore the structure of a multiprotein complex required for cells to grow normally and maintain their homeostasis.
Why did you particularly focus on microbiology and fungal cell biology during your PhD?
I wanted to learn more about cells. Microorganisms are some of the most successful cellular systems out there, and I think they are fascinating. I believed this was the right field for me. I was lucky to meet a principal investigator interested in understanding how fungal cells (hyphae) grow and acquire their characteristic tubular shape. She transmitted this interest to me, and she took me in as part of her lab. I felt grateful to find an excellent place to learn some cool science. Fungi have a characteristic cell wall, the outermost layer surrounding fungal cells.
It is composed of carbohydrates mainly and protects the fungus. It allows the organism to interact with the environment, and it also determines how the fungus grows and its tubular shape. What is impressive is that this outer layer is built from within and secreted to the exterior. I was interested in understanding the molecular and cellular mechanisms by which the fungus assembled its cell wall.
My work focused on determining the localization of some of the molecular machines (enzymes) involved in this process. I conveyed a cell wall growth model for the filamentous fungus called Neurospora crassa.
As a post doctoral associate at UMASS medical school, what is it like studying membrane trafficking and exocytosis?
The words that come to my mind are challenging but thrilling. These concepts have been in biology textbooks for many years. Yet, as scientists, we do not fully understand every detail of the molecular mechanisms involved in these vital processes.
Membrane trafficking is the mechanism in eukaryotic cells by which small molecules, like fats (lipids) and enzymes (proteins), are transported throughout the cell to maintain equilibrium (homeostasis) and grow, divide and be successful. The small molecules travel inside spherical compartments called vesicles, mainly composed of lipids.
Transporting vesicles can move from the inside out to deliver their content to the environment following the exocytic pathway. These vesicles fuse with the plasma membrane (outer cell membrane); this process is called exocytosis, and it necessary to rebuild the plasma membrane, signal neighboring cells, and secrete waste.
I study the structure of a big protein complex called the exocyst, required for the last step in exocytosis; lack of the exocyst complex associates with various human diseases. We believe that by knowing the architecture of the proteins involved, we can comprehend better the chronological order of the steps in exocytosis.
If we understand what triggers the protein complex to go from position A to position B, we will better comprehend the whole process. The aim is to create a better, more explicit model of exocytosis.
How do you create your bio-illustrations in 2D and 3D?
I became proficient in using Illustrator and Photoshop programs to create 2D illustrations to explain scientific concepts better. For example, I illustrated the Spike protein on the SARS-CoV-2 virus at the beginning of Covid times. In the lab, we discussed an article describing the structure of the Spike protein characteristic of the viral surface. The Spike protein goes from closed to open to gain access into human cells. I used the structure from the protein databank (PDB 6vyb) derived from the original article and traced the Spike protein outline with one of the “arms” in the up conformation. With illustrator, I got a simple representation of the structure.
I think the bright colors highlight the protein structure’s beauty and helped me forget a bit of the virus’s negative aspects.
I have also learned 3D modeling and illustration using the free software Blender. To make the image of clathrin-coated vesicles (shown on the previous page), a virtual seminar I attended inspired me. In membrane trafficking, a protein called clathrin assembles as a cage-like structure to help form vesicles by surrounding it as a coat. I used the PDB 1XI4 from the protein databank, further process the model in chimera (software for protein visualization), and did the final space-looking illustration in Blender. I wanted to highlight how beautiful this microscopic structure is.
Final thoughts
We have seen how Leonora creates detailed and eye-catching 2D and 3D visuals to help convey biological concepts, such as the stage before exocytosis, and the structure of the spike protein observed on the Covid-19 (SARS-CoV-2) virus. We can notice how the SARS-CoV-2 spike protein illustration above appears aesthetic with bright colors, though this is a contrast to the devastating impacts the virus has brought to humanity since that start of the pandemic. By combining her skills in both science and art, Leonora presents the hidden structures in the microbiological world in a new light.
Bio
Leonora Martinez-Núñez is a Mexican postdoctoral researcher with a PhD in Microbiology working in the field of membrane trafficking and structural biology in the US. Leonora considers herself a scientific illustrator and scientific visualization enthusiast.
She combines her passion for art and illustration with her science expertise to create scientific visuals, or bio-illustrations, to better understand and explain scientific concepts. Her goal is to celebrate science by highlighting the beauty in microscopic, almost invisible things and showing their complexity to the world.
Links
Website: https://www.leonoramartinez.com/contact
Instagram: @radiant_molecules