What can amoebas teach us about mitochondrial dynamics?
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What can amoebas teach us about mitochondrial dynamics?
Understanding how our cells function is vital for addressing some of today’s most challenging diseases, from genetic disorders to neurodegenerative conditions. At the heart of each cell is a network of structures known as mitochondria, which are essential for powering cellular activities. At the University of Central Arkansas in the US, Professor Kari Naylor is studying mitochondrial dynamics, exploring how these processes affect human health and revealing key insights into cellular function and disease.
Talk like a cell biologist
Amoeba — a single-celled organism
Cytoskeleton — a network of protein fibres in a cell that helps maintain its shape, organisation and movement, and influences mitochondrial dynamics
Dictyostelium discoideum — a species of amoeba that shares many characteristics with human cells, making it useful for studying cellular processes in cell biology research
Fission — the process by which a mitochondrion splits into two separate mitochondria
Fusion — the process by which two mitochondria combine to form a single mitochondrion
Genetic mutations — changes in the DNA sequence of a gene
Live-cell imaging — a method of observing living cells in real-time to study their processes and behaviours
Mitochondria — a cell structure that generates chemical energy
Mitochondrial dynamics — the continuous processes of mitochondrial fission and fusion that help maintain mitochondrial function and structure
Neurodegenerative disorder — a disease that causes the progressive deterioration of nerve cells, such as Parkinson’s disease
Mitochondria are often called the ‘powerhouses’ of a cell because they convert nutrients into the energy that powers the cell’s functions. However, their role extends beyond producing energy. Mitochondria also help protect cells from toxic by-products created during energy production, regulate calcium levels, and play a part in cell death – processes essential for maintaining overall cell health and survival.
Understanding how mitochondria maintain their structure and function is of great significance. When something goes wrong with mitochondrial dynamics, serious diseases can develop, including blindness, muscle atrophy and neurodegenerative disorders like Parkinson’s disease. Professor Kari Naylor, a cell biologist at the University of Central Arkansas, is investigating these processes to understand how mitochondria function and how defects in their dynamics can lead to disease.
How do mitochondria maintain their structure?
Mitochondria rely on a series of processes called mitochondrial dynamics to keep their structure intact. These dynamics include fission, where a mitochondrion splits into two, and fusion, where two mitochondria combine. This continuous division and merging allows the mitochondria to stay functional and move to where the cell needs energy most.
“To function correctly, mitochondria must have the correct shape,” explains Kari. “Much like you cannot stab a piece of food if your fork is shaped like a spoon.” If mitochondria lose their shape due to disruptions in fission or fusion, they cannot perform their essential roles properly. For example, in the disease dominant optic atrophy, the mitochondria are unable to fuse correctly, leading to blindness.
What causes mitochondrial defects?
There are many reasons why mitochondrial dynamics can be disrupted. “Genetic mutations, for instance, can cause defects in fission and fusion processes, leading to serious diseases,” says Kari. “We do not understand every defect that results from the disruption of mitochondrial dynamics, but specific genetic mutations that block fusion can result in childhood blindness or muscle atrophy.”
How do Kari and her team study mitochondria?
Kari’s research focuses on Dictyostelium discoideum, a species of amoeba, to better understand mitochondrial dynamics. This organism is widely used in cell biology because it shares many characteristics with human cells. “We use advanced microscopy techniques to study the shape and rates of division, fusion and movement of D. discoideum mitochondria after we mutate the organism’s genes or introduce chemicals that change other cell activities,” says Kari. By observing how mitochondria behave under different conditions, Kari and her team can learn more about the processes that keep cells healthy.
A key part of Kari’s research is understanding how mitochondrial dysfunction contributes to neurodegenerative disorders like Parkinson’s. Mitochondria need to divide and fuse properly to maintain their structure and function. If there is not enough fission, mitochondria can become tangled together, while insufficient fusion leads to clumps of mitochondria that struggle to move within the cell. This reduced movement can cause damage to the cell’s energy supply. These mitochondrial problems are thought to play a role in the progression of Parkinson’s disease.
Kari and her team are also examining the role of the cell’s skeleton, known as the cytoskeleton, in regulating mitochondrial dynamics. The cytoskeleton helps maintain the shape and movement of mitochondria and other cell components. “It is known that mitochondrial dynamics are dependent on the cytoskeleton in mammals and yeast, but not much is known about the cytoskeleton’s role in dynamics in D. discoideum,” explains Kari. “To determine this role, we need to analyse the interactions between the cytoskeleton and the mitochondria during mitochondrial dynamics.” By using live-cell imaging, the researchers can observe how the cytoskeleton interacts with mitochondria in real-time. This approach allows them to better understand how disruptions in these interactions might affect mitochondrial function and contribute to cellular diseases.
Reference
https://doi.org/10.33424/FUTURUM543
All photos © Naylor Lab
What role do students play in Kari’s research?
Kari’s research group is primarily composed of undergraduate students. As well as contributing to research, Kari’s students also lead community involvement and public outreach events. This experience provides students with essential skills and a solid foundation for their future careers in cell biology. “My undergraduates publish papers, write theses, and move on to become doctors, scientists, teachers and more,” says Kari.
What has the team discovered?
Kari’s research in mitochondria dynamics has already revealed some intriguing findings. “So far, we have demonstrated that D. discoideum does indeed carry out mitochondrial dynamics like in human cells,” says Kari. “Unexpectedly, we have also shown that the proteins that mediate mitochondria dynamics in humans don’t do so in D. discoideum.” This surprising finding provides a new perspective for understanding how mitochondrial dynamics have evolved.
Looking ahead, Kari’s team aims to uncover more about how a cell’s cytoskeleton influences mitochondrial behaviour in D. discoideum. By exploring these interactions, Kari’s team hopes to gain deeper insights into cellular function. Additionally, the team is developing new microscopy techniques to observe the proteins involved in mitochondrial division, fusion and movement more closely. These advancements will enhance our understanding of mitochondrial dynamics and contribute to broader scientific knowledge about cellular processes, their evolution and disease treatment.
Professor Kari Naylor
Department of Biology, University of Central Arkansas, USA
Field of research: Cell biology
Research project: The molecular mechanism of mitochondrial dynamics in Dictyostelium discoideum
Funder: US National Science Foundation (NSF)
About cell biology
Cell biology is a branch of biological science focused on the study of cells – the basic building blocks of life. This field explores the structure, function and behaviour of cells, including how they grow, divide and interact with their environment. Cell biology is integral to understanding numerous biological processes and is foundational for fields such as genetics, biochemistry and medicine.
Working in cell biology is incredibly fulfilling, especially when it comes to discovering and applying new knowledge. Researchers in this field get to explore the microscopic world of cells, uncovering how they operate and interact. This can lead to breakthrough insights into how our bodies function and how diseases develop. What many cell biologists find most rewarding is watching their research lead to real-world impacts, such as new treatments or diagnostic tools. “I am in the field of basic science, which means I ask how cells do what they do,” says Kari. “I love to see other people take my research and turn it into applied research and develop new treatments for diseases.” This impact on improving human health and advancing scientific knowledge provides a strong sense of accomplishment and purpose.
The field of cell biology is constantly evolving, presenting numerous opportunities for the next generation of scientists. Advances in technology and new discoveries open up new research fields and applications continually. Emerging areas such as cell signalling, cellular metabolism and novel cell death mechanisms offer exciting research opportunities. “Every day, new organisms and cellular processes are discovered that we need to understand,” says Kari. “For example, when I was in college, we learnt about apoptosis — programmed cell death. At the time, we thought this was the only way cells could protect the body from damaged cells. Now, we know there are many other processes, such as ferroptosis, pyroptosis and necroptosis, just to name a few.” This dynamic environment ensures that cell biology remains a rewarding field, offering opportunities for those interested in contributing to innovative research and advancing our understanding of life at the cellular level.
Pathway from school to cell biology
“To pursue a career in cell biology, I recommend taking biology, chemistry and physics,” says Kari. “As you progress to more advanced levels, taking microbiology, cell biology and biochemistry are also very useful.”
Getting involved in lab work or summer internships is a great way to apply what you have learnt in class and build valuable practical skills to prepare you for a successful career in the field.
Find out about any events held at your local university or college. For example, the University of Central Arkansas holds a range of events to give high school students an insight into undergraduate studies.
Explore careers in cell biology
Kari recommends exploring professional societies, such as the American Society for Cell Biology and the American Society for Microbiology, that offer resources, networking opportunities and professional development for those in the field.
Subscribing to newsletters and podcasts from institutions like the Johns Hopkins Bloomberg School of Public Health can help you keep up with the latest research.
According to Salary.com, the average annual salary for a cell biologist in the US is $58,000.
Q&A
Meet Kari
What experiences have shaped your career as a cell biologist?
I did not know what I wanted to do for a career, but I always loved my science classes. My favourite was microbiology, so I decided to major in it. I was hired to prepare materials for an entry level biology course, and then, a new faculty member hired me to help her do research. I had no idea what I was saying yes to, but I loved it so much that I decided to go to graduate school. In graduate school, I joined a cell biology lab studying mitochondrial dynamics and was a teaching assistant. These experiences showed me that I loved research but wanted significant teaching as well, so I looked for a university that prioritised teaching and also supported research labs.
What are your proudest career achievements?
My proudest moments are when my students find their own path. One example is when one of my undergraduate research students decided to earn a master’s degree with me, and then went on to get a doctorate. In his doctoral programme, he decided that research wasn’t right for him, and now he runs his own brewery at a restaurant in Florida. I am so proud that I played a role in him finding his way and his own success.
What are your aims for the future?
I have been at the University of Central Arkansas for 18 years now, and my aims are to continue doing what I am doing: finding funding to support my students, teaching and mentoring, and finding ways to make the university even better for staff and students.
How do spend your free time?
I read, quilt, hike and support my children in all their activities!
Do you have a question for Kari?
Write it in the comments box below and Kari will get back to you. (Remember, researchers are very busy people, so you may have to wait a few days.)
Learn more about the fundamentals of cell biology:
www.futurumcareers.com/an-educational-journey-through-cell-biology
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