Biochemical controls: handling stress (Introduction)

by David Turell , Monday, October 16, 2023, 18:59 (402 days ago) @ David Turell

Cells have special programmed mechanisms:

https://phys.org/news/2023-10-peering-cells-stress.html

"This "heat shock response" of cells is a classic model of biological adaptation, part of the fundamental processes of life—conserved in creatures from single-celled yeast to humans—that allow our cells to adjust to changing conditions in their environment.

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"In the new study, published October 16, 2023, in Nature Cell Biology, they combined several new imaging techniques to show that in response to heat shock, cells employ a protective mechanism for their orphan ribosomal proteins—critical proteins for growth that are highly vulnerable to aggregation when normal cell processing shuts down—by preserving them within liquid-like condensates.

"Once the heat shock subsides, these condensates get dispersed with the help of molecular chaperone proteins, facilitating integration of the orphaned proteins into functional mature ribosomes that can start churning out proteins again. This rapid restart of ribosome production allows the cell to pick back up where it left off without wasting energy.

"The study also shows that cells unable to maintain the liquid state of these condensates don't recover as quickly, falling behind by 10 generations while they try to reproduce the lost proteins.

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"Ribosomes are crucial machines inside the cytoplasm of all cells that read the genetic instructions on messenger RNA and build chains of amino acids that fold into proteins. Producing ribosomes to perform this process is energy intensive, so under conditions of stress like heat shock, it's one of the first things a cell shuts down to conserve energy.

"At any given time though, 50% of newly synthesized proteins inside a cell are ribosomal proteins that haven't been completely translated yet. Up to a million ribosomal proteins are produced per minute in a cell, so if ribosome production shuts down, these millions of proteins could be left floating around unattended, prone to clumping together or folding improperly, which can cause problems down the line. (my bold)

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"Using these combined imaging tools, the researchers saw that the orphaned proteins were collected into liquid-like droplets of material near the nucleolus (Pincus used the scientific term "loosely affiliated biomolecular goo"). These blobs were accompanied by molecular chaperones, proteins that usually assist the ribosomal production process by helping fold new proteins. In this case, the chaperones seemed to be "stirring" the collected proteins, keeping them in a liquid state and preventing them from clumping together.

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"'I think a very plausible general definition for cellular health and disease is if things are liquid and moving around, you are in a healthy state, once things start to clog up and form these aggregates, that's pathology," Pincus said. "We really think we're uncovering the fundamental mechanisms that might be clinically relevant, or at least, at the mechanistic heart of so many human diseases.'" (my bold)

Comment: this study shows how cells function constantly at very high speeds, allowing mistakes to occur. In theodicy discussions the issue of God's responsibility can be answered by realizing the molecules are free-floating and changing shapes automatically. Unintentional mistakes will occur and are not God's fault. Here is where proportionality offers a response. The cells make millions of proteins per minute. With an occasional mistake now and then a percentage of disease will eventually appear. This is what critics of God complain about. These are not God's direct mistakes. If the cells did not operate at these speeds life would not exist. What is important is to recognize God's goodness in giving us life. God recognized the problem and gave the cells editing systems. But they have the same problem, very high speed is needed, so even those editing systems can fail producing eventually an aggregate of diseases. Understanding the logical point of proportionality answers the criticisms in theodicy.