Cell Signals and Creationism

Lately, creationist rhetoric seems to increasingly mention the idea that if scientists really understood evolution, life, and biology, then why don’t they just create it themselves, as a kind of proof of concept? This rhetoric usually includes a statement like: “They can’t even create a simple cell … ”

A repost

This is very annoying, and displays either creationists’ excellent ability to frame their arguments or their utter stupidity. In fact, a cell is the most complicated thing going in biology. A cell is more complicated than an organism that is made up of cells, assuming that you don’t count the complexity of individual cells in that measure. An ecosystem is simple compared to a cell.

Proof of this complexity, confounded by unimaginable smallness of cells and their parts, is the steady pace of discovery of how cells actually work. The most recent finding is from Brown University and it relates to signal transduction. Signal transduction is the means by which cells communicate.

An important part of signal transduction is changing the function of specific proteins so that they either do or do not affect some other protein down the line in a cascade of events. One of the more common ways in which this is done in cell signaling is phosphorylation, in which proteins involved with cell receptors are altered such that the receptors turn on and off. One of the most common phosphorylation process related to signal transduction is known as “Tyrosine phosphorylation” which involves adding a little molecule to a protein in a way that significantly changes the way the protein folds itself up, and thus, how the protein functions (because at this scale, shape equals function). It may have the effect of closing a door or window in the case of a receptor site, but it does so by messing up the door or window so it just becomes part of the wall, in a sense.

While tyrosine phosphorylation is not by any means the most common phosphorylation, it is easy to isolate the phosphorylated molecules, so they are heavily studied.

An important process is when phosphorylation of receptor sites leads to a cascade of events that ultimately changes gene expression and thus, depending on circumstances, an appropriate immune response. The newly reported research identifies a previously not understood step, acetylation, in this cascade of events. Acetylation is a key part of the process, and if it does not happen, then there is no immune response.

It is not like acetylation was not previously known. Acetylation is just like phosphorylation … but instead of adding a phosphorus group to a protein, an acetyl group is added to the protein, again, changing its shape and thus its function. What this new research shows is that there is an acetylation step that is critical in a particuar immune response. Yet one more tiny, yet important part of the very complex workings of a cell is thus identified.

Comments

  1. #1 Stella
    October 8, 2009

    “If you love cells so much, why don’t you marry one?!”

    Creationists sound eerily similar to children.

  2. #2 NoAstronomer
    October 8, 2009

    “A cell is more complicated than an organism that is made up of cells.”

    That was an epiphany I had in high-school. We were studying how the cell wall is constructed to allow stuff in and out.

  3. #3 chris
    October 8, 2009

    Dawkins’ new book has an excellent chapter on how cells do what they do, and how two cells merging at conception eventually become hunderds, or thousands, or millions of specialized cells in an adult body.

    It covers a lot of topics necessarily cursorily, but with enough detail that I now understand much better, to the extent that a person with a degree in history who didn’t pay much attention during high school biology can understand how cells work.

  4. #4 other Chris
    October 8, 2009

    no Chris, you don’t understand how cells work. don’t take it personally. Nobody does. Not even cell biologists understand how cells work. We understand little pieces of how cells work, or have vague big picture ideas of patterns in cell functions, but the overall process is so mind-bogglingly complex that scientists often spend their entire career studying, for example, a single protein, or a part of a protein, or a few amino acids of a protein.

    I’m glad someones studying that stuff, and I’m glad it’s not me.

  5. #5 TL
    October 8, 2009

    If creationists understand God so well, why can’t they just create one themselves?

    …oh, yeah, huh. They did.

  6. #6 Jared
    October 8, 2009

    NoAstronomer, do you mean the cell membrane? Cell walls are plant/archae/bacterial structures while all kingdoms have membranes.

    other chris, I don’t know of any cell biologists that study very specific aspects of a single type of cell; I know many that study specific cell types (bowman’s capsule cells; E. coli; amacrine cells…) but none that specialize in only a specific pathway within those cells.

    As for the complexity of cellular function, part this complexity of cells stems from the myriad of cell types and specializations in eukaryotic organisms. If we instead focus on organisms with only a single cell type (a few species of bacteria) then our understanding of these cells increases considerably. The biggest issue (I think) in cell biology is learning which segments of the DNA are actually expressed in a given cell type and how these segments are regulated.

    As far as “understanding how cells work,” there are some very basic concepts such as signal transduction and genetic regulation which are fairly central. Concepts such as siRNAs, snRNPs, quorum sensing, TATA boxes (or AT-rich sequences for you prokaryotic fans) and so forth are specific cases of regulation, post-transcriptional modification, and so forth, but they follow the basics of affecting expression at some point. While we don’t know every single pathway and every single molecule involved, we do have a fairly decent cursory understanding of cellular responses. The mind-bogglingly complex overall process follows some very easy-to-understand mechanisms with a wide variety of modifications. The difficulty is trying to condense all of these examples into general patterns necessary for an introduction into to the topic while not blatantly contradicting specific examples.

  7. #7 Jared
    October 8, 2009

    I forgot about the researcher that genetically manipulates anaerobic metabolism in yeast and brews his own beer. I somehow don’t think that was coincidental, although he’s been brewing beer since his early college days, I think the beer brewing led him to study yeast metabolism…

  8. #8 Matt
    October 9, 2009

    I completely agree with what you’re saying, it is amazing what goes on in various cell types. I’m taking a physiology class right now and we just got done studying how cells in the nervous system conduct signals. There is an absolute wealth of information that was previously not within my understanding.

    The fact that a single molecule from ATP can break off and cause phosphorylation of a membrane protein which changes structure causing the polarity inside or outside the cell to change (membrane potential) is amazing. Thus allowing the movement of intracellular or extracellular particles. All this to maintain the homeostasis of the cellular environment and this occurs how many times a minute??? This doesn’t include various other methods by which particles move in and out of cells.

    All this because of a single molecule is nothing short of amazing. It’s no wonder creationists don’t understand…..they don’t want to.

  9. #9 Tracy
    October 9, 2009

    It’s odd that the same people that argue that life is too complicated to have evolved also seem to argue that life is so simple we should have been able to make it ourselves by now. But really, I get giddy sometimes thinking about cells. They’re complex. They’re beautiful. I am devout in my pursuit of understanding them. And it is true, they are so complex that many researchers do spend their lives on understanding how one protein functions in one cell type. I’ve spent the last four years studying one protein for my PhD thesis, which has been studied for almost twenty years now, and still, no one knows quite what it does, much less why. Should my publication shed some light on this protein, it will without doubt be found that in another cell type that it does something different, perhaps subtly, perhaps dramatically. It wouldn’t be surprising at all if someone follows up on the research Greg posted about and found that phosphorylation and acetylation have a different effect on that protein in the context of another cell type, or to make it even more complex, it may even have a different effect within the same cell type, depending on the state of the cell. (Is the cell dying, is it in a highly oxidative state, is it about to divide?) Cells and life are tirelessly, endlessly, frustratingly complex. Whether life arose spontaneously, or some greater intelligence we cannot understand gave things a nudge, it seems an insult to the process of creating life to ignore its awesome complexity. (I mean, six days, really? No wonder we’ve got an appendix.)