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About the Institute

Profile of John Rubinstein

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Dr. John Rubinstein

Dr. John Rubinstein, PhD

  • Scientist, Molecular Medicine
  • Assistant Professor, Departments of Biochemistry and Medical Biophysics, University of Toronto

1. Where are you from? /Where did you study?
I grew up in the greater Toronto area (GTA), in what used to be called North York and I attended the Academy Program at Earl Haig Secondary School. I did my B.Sc. at the University of Guelph where I started in biology and ended up with a degree in physical sciences. Then, I went to Cambridge, England where I did my PhD in the Medical Research Council laboratories working with Sir John Walker, who won the Nobel Prize for Chemistry in 1997, and Richard Henderson, who is a pioneer in the techniques that I use in my lab. I stayed in Cambridge for a short post-doctoral fellowship after my PhD and then came back to Toronto for another short post-doctoral fellowship before taking a position as a scientist here at SickKids.

2. What are you researching right now?
Our lab uses electron cryomicroscopy, a type of microscopy that is able to image molecules with the potential for atomic resolution, to look at structures of membrane protein complexes. These are large assemblies of proteins that exist in cell membranes. Most of our work has been looking at membrane protein complexes that either make adenosine-5'-triphosphate (ATP), the cell’s energy currency, or use ATP to pump protons to acidify compartments in cells. These are actually closely related types of membrane protein complexes. These complexes have various functions in healthy cells and also in disease processes. For example, osteoclasts, the cells that make up bone minerals, use the proton pumps to dissolve bone minerals. If the activity of osteoclasts isn’t properly balanced by the activity of the cells that deposit bone minerals, the disease osteoporosis can occur. Some types of cancer cells use the proton pumps to acidify the extracellular environment in order to invade surrounding tissues and spread. Macrophages, a type of white blood cell, use these proton pumps to try to destroy bacteria that they trap within themselves. But certain bacteria shut down the pump and thrive inside the macrophage. Understanding how these protein complexes function is essential for understanding how these disease processes occur.     

3. Who is your all-time favourite scientist, and why?
If I had to choose one, I would choose Louis Pasteur, but not for the reason that most people would think. Pasteur is most famous for pasteurization, the process of heating food to delay spoiling. However, he also did some extremely elegant experiments that combined physics, biology and chemistry. In one of these experiments he looked at how a solution of the chemical tartaric acid rotated polarized light when it was extracted from yeast but didn’t rotate light when it was synthesized in a laboratory by chemists. He realized that crystals of solid tartaric acid from yeast always had a very specific asymmetric shape, while from the lab they had the same specific shape but also the mirror image of that shape. He separated the left- and right-handed crystals and showed that he could use them to make solutions that rotated polarized light in either direction. From there, he proposed that the chemical tartaric acid could have a left- or right-handed symmetry. This was an amazing deduction when very little was known about molecular structure and it has to be my favorite single experiment of all time.

4. What in your opinion is the single most important scientific breakthrough, and why?
This is an even harder question to answer than the previous one, but I would pick John Dalton’s development of modern atomic theory. He figured out that matter is made up of atoms. Not only is that essential to our understanding of matter, but more importantly it defined how a lot of modern science works. In order to understand something we try to understand its building blocks, whether they are atoms, photons, genes, or cells. Once you understand these building blocks you can start to understand how they fit together to make the system that you are interested in. I think that approach was first taken successfully with the study of matter and its division into atoms.

5. What are your major interests outside the lab?
In high school we had the option of doing a marine biology field study where we could learn how to scuba dive and go to Jamaica and of course I took this opportunity. Since then, I’ve been an avid scuba diver and diving instructor and I’m still involved in teaching scuba diving at the Hart House Underwater Club at the University of Toronto. At every university I’ve studied or worked at, one of the first things I do when I arrive is find the scuba diving club. I also very much enjoy cooking and baking – it’s like doing experiments that you can eat!

6. Why science?
Both of my parents have PhDs in physics and I have several other relatives who are physicists. Seeing the world as a scientist has always been a natural thing. I guess my rebellion as a teenager was deciding to study biology, but then as I went through university I realized that looking at biology through the lens of physics was an extremely powerful and rewarding approach.

7. Why SickKids?
SickKids is an interesting place. It’s a high-powered research institute where you can really get things done, but it’s also a friendly and supportive environment. It’s nice to work with colleagues who treat you as friends and also have the potential to do important science.

8. What is the most controversial question in your field right now?
I have a biological background where we are interested in membrane protein complexes and a technological expertise where we are interested in developing a type of microscopy so that we can see what protein complexes look like at extremely high resolution. With the technology, there is the question of how far we can actually go. In theory, we should be able to see the atomic structure of these protein complexes but in practice no one has gotten there yet. There are people who think we are already reaching the limit of the technique and then there are the optimists, like me, who think that we can take things much further and learn even more about protein structure.

9. What are you reading right now?
I recently discovered the American writer Barbara Kingsolver and I’ve been working my way through her novels. I first read The Lacuna, which won The Orange Prize for Fiction, and I’m now reading The Poisonwood Bible. She is incredibly talented.

10. If you could give one piece of advice to someone considering a research career, what would it be?
It’s a funny time in research because with the economic downturn funding sources have decreased. It’s hard to predict what things will look like in a few years. However, I think for someone who is really driven to do research there will always be opportunities, so if you have the drive you should go for it.

11. What does the Research & Learning Tower mean to you?
One of the most important skills for a scientist to have is knowing when and whom you should ask for advice. But knowing who to ask doesn’t help if you don’t have an opportunity to talk to that person. In The Research & Learning Tower, the people who you would want to ask will be nearby and accessible. We’ll all have the opportunity to bump into each other in the coffee rooms and hallways and ask the questions we need to ask. This will continue to drive our science forward.

July 2011

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