Uncommon Descent Serving The Intelligent Design Community

How cells signal that they should be killed


And why this cell death or “apoptosis” is essential for survival:

“Every day, ten billion cells die and are engulfed by blood cells called phagocytes. If this didn’t happen, dead cells would burst, triggering an auto-immune reaction,” explains iCeMS biochemist Jun Suzuki, who led the study. “It is important to understand how dead cells are eliminated as part of our body’s maintenance.”

Scientists already know that dead cells display an ‘eat me’ signal on their surface that is recognized by phagocytes. During this process, lipids are flipped between the inner and outer parts of the cell membrane via a variety of proteins called scramblases. Suzuki and his team have already identified several of these lipid-scrambling proteins, but some of their activation mechanisms have been unclear…

Specifically, the scientists found that cell death signals lead to a nuclear protein, called XRCC4, getting cut by an enzyme. A fragment of XRCC4 leaves the nucleus, activating Xkr4, which forms a dimer: the linking of identical pieces into configurations. Both XRCC4 binding and dimer formation are necessary for Xkr4 to ultimately transfer lipids on the cell surface to alert phagocytes.

Kyoto University, “Eat Me: The Cell Signal of Death” at Neuroscience News

Again, a complex signalling system that supposedly just so happened and in this case it doesn’t function for the protection of the cell but for it’s elimination — look, if Darwinism really worked, many gravel pits would be full of newly forming life. They probably have all the ingredients. So why doesn’t survival of the fittest work its magic in creating massive complexity today?

The paper is closed access.

See also: Why do many scientists see cells as intelligent? Bacteria appear to show intelligent behavior. But what about individual cells in our bodies?


Leave a Reply