Finding More Gifts in the Cellular Stocking
Improving techniques are allowing biochemists to find surprising new things in cells. Here are some recent examples.
Researchers watch biomolecules at work: Method development advance allows deeper insight into cellular processes (Science Daily): “If we want to open a Christmas season walnut, we usually use a nutcracker,” this article begins, leading into a discussion of a new magnetic technique developed at the University of Bonn to measure distances within large molecules. Looking at a large protein named cytochrome P450, “With our method, we were able to precisely measure the distance between two areas of the cytochrome to a fraction of a millionth of a millimeter,” they boast.
How to see living machines (Phys.org): To get our attention, this article begins, “It sounds like something out of the Borg in Star Trek. Nano-sized robots self-assemble to form biological machines that do the work that keeps one alive. And yet something like this really does go on.” In Illustra’s new film Origin, Paul Nelson says that even the simplest known cell is made up of molecular machines, and lots of them. This article doesn’t dispute that. “These molecular machines are so complex, yet so tiny, that scientists today are just starting to understand their structure and function using the latest microscopes and supercomputers.” The best model yet is coming from three universities. The article tells how they peer deeper and deeper into the cell with modern methods. “For the first time, structures have been detailed of the complex groups of molecules that open up human DNA,” they say.
Multi-institutional collaboration uncovers how molecular machines assemble (Science Daily): We’ll just tease with the opening paragraph about what takes place in your cells every hour. Biochemists at Salk and Scripps want to slow them down enough to see what’s going on:
Ribosomes — macromolecular machines consisting of RNA and proteins that twist, fold and turn — are responsible for making all of the protein within a cell and could hold the key to deciphering a range of diseases. Despite the intricacies of ribosomes, cells are able to churn out 100,000 of them every hour. But because they assemble so speedily, researchers haven’t been able to figure out how they come together.
Atlas of the RNA universe takes shape (Phys.org): Biochemists have known about the big molecules—DNA and proteins—for decades, but it wasn’t that long ago when a “hidden universe” of small RNA molecules came into view. Understanding these small segments of RNA transcribed by genes is part of a “revolution in biology” going on. Not just pieces of flotsam in the cell, “they act as a subtle and extremely sophisticated network of gene regulators,” cell biologists are learning.
Small but mighty: Tiny proteins with big roles in biology (Science Daily): Another hidden universe in the cell is just coming to light: the frontier discovery of “microproteins” or polypeptides. They’ve been hard to detect till now, but Salk scientists located one called “NoBody” that has an important role in the degradation of spent messenger RNA (mRNA). These spent mRNAs join with proteins to form P-body granules, the first step in mRNA recycling. It turns out the process doesn’t work without NoBody around. That sounds like a “Who’s on first?” joke, but this real microprotein is on the cusp of unlocking a whole unseen universe of other microproteins with important functions in the cell. So far they have found 400.
Following the magnets (PNAS): Bacteria have little magnets inside that help them navigate. In this paper, “Measuring spectroscopy and magnetism of extracted and intracellular magnetosomes using soft X-ray ptychography,” an international team is investigating how magnetotactic bacteria assemble crystals of magnetite into sensors for movement. “Our results help us to understand how the cells biomineralize magnetosomes and their function in the cell ecophysiology,” they say, outlining the significance of their work. “In addition to demonstrating a large improvement in spatial resolution relative to earlier nonptychography studies, the results presented provide insights into magnetosome biomineralization.”
Following the Model T to see how cells move (Phys.org): A team in Sweden is following T cells around to learn how they move. “To be able to move, the cell must attach itself to a surface and use its front to push to exert the force it needs,” they know. To do this, the cell has to convert chemical energy into mechanical force. That’s a difficult trick. It has taken this team three years just to find out how one protein part becomes active.
The process of DNA packaging in cell nucleus revealed (Phys.org): How do you get almost 7 feet of DNA packing into a tiny cell nucleus? It’s one of the wonders of biological design how cells coil up several times into supercoils that make up chromosomes. Russian scientists are learning how different cell types pack their DNA to keep the genes they need accessible. The hierarchical layering is loose enough to allow for flexibility. This article also discusses epigenetic inheritance.
A surprising finding shines new light on the largest group of human proteins (Medical Xpress): The large family is the C2H2-zinc finger set of proteins, important for controlling gene activity in many ways. The surprise is that “there’s almost as much diversity in the protein-protein interactions as there is in the DNA binding sequences,” Toronto scientists say. “It tells us that the way the C2H2-ZF proteins work is almost certainly more complicated than we would have expected.”
Pore architecture of TRIC channels and insights into their gating mechanism (Nature): Like to build your muscles? You have no idea what is going on inside those muscle cells. Just read the abstract of this paper to see a tiny bit of what goes on when you flex. For starters, “Intracellular Ca2+ signalling processes are fundamental to muscle contraction, neurotransmitter release, cell growth and apoptosis. Release of Ca2+ from the intracellular stores is supported by a series of ion channels in sarcoplasmic or endoplasmic reticulum (SR/ER).” You get the picture. Read more if you dare.
How about some moving pictures? Had enough talk? Let’s watch some new video clips Phys.org announced. If you click on the links, you can watch three videos by CellDance that won awards at the ASCB (American Society for Cell Biology) meeting in San Francisco:
- “Cell Division Live and Up Close”
- “The Big Squeeze: What Dendritic Cells Do to Fight Infection”
- “Discovery Inside Living Cells in Multicellular Organisms”
Read the Phys.org article for film descriptions. The article sums up the videos in an awesome way:
Jagesh Shah of Harvard Medical School, who serves as PIC’s Executive Producer for Celldance Studios, hailed this year’s videos. “Our storytellers and their producers have put together a magnificent set of ‘cell stories’ told in spoken word, animation and, of course, live microscopy,” says Shah. “Live cell microscopy can evoke the wonder and awe of complex molecular processes as it reveals the beautiful cellular dance of life. This year, all three contributions deepen that wonder and awe.“
Even these beautiful whole-cell images, though, fail to capture the intricate work going on at the molecular level. These are just a few recent reports in a rapid-fire series of discoveries coming from biochemistry labs around the world. The ability to see cells at work is a gift that keeps giving.
Notice that in living cells, the closer you look, the more complex things get. In man-made designs, it’s the opposite: things get less complex as you look closer. That’s the awesome wonder in God’s creation – and the daunting challenge for materialists.