How Would You Explain Lipids to Someone Who Had Never Heard of Them?
When I want to explain my research to someone not from a science background, I normally opt to talk about it through a fundamental process that I am sure they will have heard of. Cell division is usually the best vehicle, and it segues nicely into a discussion about what I want to do in research in the long term if the conversation goes that far.
I start by explaining that we can draw an analogy between a cell and a house. If one were an alien and wanted to study houses, the things that move and go in and out of the house would probably be the first things that would gain one’s attention; the water, electricity, people and so on. However, I suggest, if you put the materials that allowed all of those things to happen together, a house would not emerge. A pile of pipes, windows, wires and so on is the contents of a skip and not Hampton Court Palace.
In terms of the raw material, the difference between the pile of stuff and the Tudor-Baroque masterpiece I mentioned can be summed up as the bricks. This is where I draw it back to lipids: they are a lot like bricks, I say. They are the bricks of the cell. Individually, they are unexciting and almost pointless. When put together in a coherent manner, great structures can emerge—everything, in fact, from a royal residence in Surrey, to a two-up-two-down in the east Midlands.
That is a neat explanation and usually satisfying, and that does not last longer than half a glass of merlot. Sometimes their interest goes further, and so I take the opportunity to push things up a notch; I take a slightly different approach. I explain that in terms of cells, we know a lot about DNA and how it behaves when cells divide. I mention Rosalind Franklin. Then I mention that proteins have been studied extensively and that we know that they make up some important molecular machinery of the cell. I mention that Nobel prizes have been won by British scientists for work on individual proteins in this story (Sir Tim Hunt and Sir Paul Nurse). Then comes the gap in our knowledge: the cell membrane.
Despite a great deal of research effort into cell division and related processes, like vesicle budding, I say that we know little about how membranes expand, bend and divide in living cells (in vivo). There is evidence about lipid behaviour from studies of model systems, and so we are confident of the basics. We understand about different types of lipid and the different sorts of assemblies they form. I also say that we know there are an amazing number of distinct lipids but we do not know how these might change in the process of cell division.
However, breaking news sheds light on the role of lipids in living systems. Some recent work by Atilla-Gokcumen et al.  has indicated that the concentration of certain lipids does change during the cell cycle. This exciting work, that became available to read in the journal Cell in January 2014, reports that eleven lipids with known chemical structures accumulate in dividing cells. This set includes phosphatidylinositol, several sphingolipids, phosphatidic acid, and a phosphatidylserine as well as two pseudo-lipids (a triglyceride and a sterol derivative).
This discovery shows that lipids may have a physical role in the process of cell division. This is a significant step forward; much of the evidence to date has been limited to model systems [2,3], has been theoretical discussion  or a best guess based on thermodynamics .
One of the reasons this discovery is important is that it is not an end in itself. Like virtually all good science, it opens up a multitude of options. It invites investigation of the behaviour and interactions of those lipids that increase in concentration in the run up to cell division. It begs the question of which lipids decrease in concentration during this process, and why. It invites fresh consideration of the evidence about those lipids that have been highlighted. It also invites interest in what changes to the lipid profile occur in other mammalian cells, and even in simpler organisms (I am working on bacteria at present, for example).
We have therefore had our appetite partly satiated and partly whetted, all at once. We have learnt a bit more about the physical process of cell division, with its connections to everything from cancer to the repair of a paper cut, and more fundamentally, that a class of molecules traditionally thought unexciting, may be on the brink of celebrity.
 G. E. Atilla-Gokcumen, E. Muro, J. Relat-Goberna, S. Sasse, A. Bedigian, M. L. Coughlin, S. Garcia-Manyes, U. S. Eggert, Cell, 2014, http://dx.doi.org/10.1016/j.cell.2013.12.015.
 X. Mulet, R. H. Templer, R. Woscholski and O. Ces, Langmuir, 2008, 24, 8443–8447. http://pubs.acs.org/doi/full/10.1021/la801114n.
 S. Furse, N. J. Brooks, A. M. Seddon, R. Woscholski, R. H. Templer, E. W. Tate, P. R. J. Gaffney, O. Ces. Soft Matter, 2012, 8, 3090-3093. DOI: http://dx.doi.org/10.1039/c2sm07358g.
 S. Furse, S. Liddell, C. A. Ortori, H. Williams, D. C. Neylon, D. J. Scott, D. A. Barrett, D. A. Gray. , Journal of Chemical Biology, 2013, 6, 63-76. DOI: 10.1007/s12154-012-0090-1 .
 H. T. McMahon, J. L. Gallop; Nature, 2005, 438, 590-596.
One response to “How Would You Explain Lipids to Someone Who Had Never Heard of Them?”
You must log in to post a comment.
[…] Ben-Zvi et al. ), it cannot replace PI in its functions—PI has been found to be significant in cell division but it is also the precursor to several important signalling lipids. However, when the pool of […]