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Life Inside a Cell
Roland Piquepaille writes "Harvard University has decided to use animations as a tool to enhance the performance of its students in biology. And it selected XVIVO's animation studio to take Harvard University students on a 3D journey. Among other realizations, the company delivered an eight minute animation titled 'The Inner Life of the Cell,' which was presented at Siggraph 2006 in a condensed form. This extraordinary animation explores 'the mechanisms that allow a white blood cell to sense its surroundings and respond to an external stimulus.' Harvard University expects a performance improvement of its biology students of almost 30% by using such visualization tools."
A down-on-his-luck American guy having a deep philosophical discussion with two Mexican cockroaches in a jail cell south of the border. If I'm not mistaken, I think Hemingway wrote that.
Well, I am a bit of a biologist (I'm a med student with a masters in physiology), so I'll see if I can't provide a bit more detail...
The initial shot of a blood vessel is way bigger than a capillary (more like an arteriole), but those are certainly WBCs crawling along the inside. Those aren't cilia, but rather a variety of different cell adhesion molecules (CAMs), and cell recognition proteins.
The "platforms" floating around on the exterior surface of the cells are likely lipid rafts (which are quite fascinating, actually - a select, extremely hydrophobic lipid type accumulates around some proteins, and in some cases seems to dictate how and where they move around the exterior of the cell. In fact, they seem to be connected to the cytoskeleton on the inside of the cell - really cool stuff).
Most of what we see from here on out is not specific to WBCs, but rather processes that all cells go through. Those are actin microfilaments which form a mesh for structural support on the outer edge of the cell (near the membrane). Throughout the cell there are microfilaments, intermediate filaments, and microtubules, which give the cell structure, and more importantly, a framework for the movement of various organelles and vesicles around the inside of the cell (as we see in a little bit).
These are actin filaments being assemble initially (and then cleaved, and disassembled), and then after that microtubules are formed. They actually form in a very ordered linear manner like this. MT's form in long sheets that then fold over and seal to form a tube, then upon disassembly chip off, almost like shards of glass. MT's frequently fracture/shatter, while actin just breaks.
The part with the vesicle being towed along the MT is very cool - the parent post is quite right about the unrealistic steadiness of this molecule, but of course this is really the case for all the molecules. That tow molecule is probably either a kinesin or a dynein - these molecules are kind of like myosin (myosin and actin are what allow your muscles to contract), and one moves in one direction down a MT and the other moves in the opposite direction. We also see a distance shot of some centrioles (which are also composed of microtubules). Centrioles serve to anchor the microtubules that connect to the chromosomes and pull them apart during cell division. There are MT strands shooting out in all directions from the centrioles. One side anchors them to the cellular membrane and the other connects to centromere of the chromosomes.
Yep, those are definitely mRNA's shooting out of the nuclear pores. They form a ring as the two ends form a complex that initiates translation of the mRNA into protein. The ribosomes then latch on and start cranking out protein. As the protein emerges from the ribosome we can see it start it folding process. Protein folding is a very complicated and intricate process. If a protein is misfolded it may simply not work, or it may cause a disease state. Creutzfeldt-Jakob disease (caused by mad cow disease in some instances) is caused by misfolded proteins that then cause other proteins to misfold (it's a prion encephalopathy).
We then see some sort of protein-protein interaction occurring randomly out in the cytosol of the cell. This could be any number of things, but looks to me like a signaling protein interaction. That newly formed protein dimer could then float off and effect some other cellular process (presumably something those two proteins couldn't do by themselves). Also, that big gray thing in the background that they float by - if I had to wager a guess, I'd say that was a mitochondria.
We then see a protein fold through a membrane in the rough ER.
We then see what looks like vesicles budding off of the ER and floating off, presumably to the Golgi apparatus, which is what we see next, right after more of the vesicle being towed again. The Golgi preps things for extracellular and intracellular transport. The golgi often sends the proteins it modifies