Body Design Extends to the Cell

From the whole body to each individual cell
we appear engineered for a purpose

Everything in balance? How a molecular switch controls lipid metabolism (University of Basel, 4 July 2023). A molecular switch: what does that sound like? Exactly what it means in engineering: a control mechanism to start or stop a process. This switch is named “Arf1” and it tells mitochondria to let lipids in, so that they can be converted into stores of the energy molecule, ATP. Its activity helps regulate our fat metabolism.

“Arf1 is a familiar protein to us. We already know that it has several functions in the Golgi apparatus, the cell’s sorting station. We have now discovered that Arf1 also plays a role in regulating energy metabolism in the mitochondria”, explains Dr. Ludovic Enkler, first author of the study. “Arf1 ensures the transport of lipids from lipid droplets to mitochondria.” The researchers assume that Arf1 alters the environment of the contact site between the lipid droplets and mitochondria, enabling lipids to enter the mitochondria.

When the body signals a need for energy, Arf1 allows lipids to enter the mitochondria. Once the energy demand is met, the transport is stopped. “Thus, the system only works when the feedback loop of the energy requirements works,” says Ludovic Enkler.

When Arf1 fails to bark, the whole body’s fat storage can get out of balance, leading to obesity and cardiovascular disease.

Scientists reveal how collagen’s weak sacrificial bonds help protect tissue (Heidelberg Institute for Theoretical Studies via Phys.org, 3 July 2023). Sacrifice can be a good design strategy. When a predator catches a lizard by the tail, the lizard can sacrifice the tail and escape. Did you know that collagen, the most abundant protein in the body, uses a sacrifice strategy? That’s what researchers at the University of Heidelberg found.

Scientists at the Heidelberg Institute for Theoretical Studies (HITS) have revealed how the rupture of weak sacrificial bonds within collagen tissue helps to localize damage caused by excessive force, minimize negative impacts on the wider tissue, and promote recovery.

The weaker bonds, being first to go, distribute the energy and keep the damage localized. Otherwise tissue damage might be catastrophic. Instead, repair mechanisms have a quicker and faster job after the stress is removed. What does the team think of this design?

“Collagen’s remarkable crosslink chemistry appears to be perfectly adapted to handling mechanical stress,” says Frauke Gräter, who led the research at HITS. “By using complementary computational and experimental techniques to study collagen in rat tissue, our findings indicate that weak bonds within the crosslinks of collagen have a strong propensity to rupture before other bonds, such as those in the collagen’s backbone. This serves as a protective mechanism, localizes the detrimental chemical and physical effects of radicals caused by ruptures, and likely supports molecular recovery processes.”

‘Traffic control’ system for mucin and insulin secretion identified (Center for Genomic Regulation via Phys.org, 3 July 2023). Traffic control implies a knowledge of a result and a strategy for maintaining efficient flow of materials. That’s what’s involved in the creation of insulin and mucus, two protein-based materials that have vital roles in the body.

Mucins, the main component of mucous, form a protective barrier and lubricant on our body surfaces such as the respiratory and digestive tracts. Humans secrete roughly one liter of mucins per day, which are released by specialized cells in a controlled manner to ensure the right quantity for proper bodily functions.

One only has to recall the last bad cold to remember the messy consequences of too much mucus flowing. In healthy times, the amount (a liter a day) is carefully regulated within cells. To get outside where it is needed, it has to go through the gatekeeper.

Cells store proteins like mucins and insulin in sacs or “granules.” When the cell needs to release these substances, the granules attach to the cell’s outer layer, the membrane, and release their contents outside. The study found that a protein known as tetraspanin-8, present on the cell membrane, acts like a gatekeeper during secretion, deciding which granules containing mucin or insulin get to attach to the membrane and when.

This implies that the gatekeeper gets signaling from the outside to know the amount needed, and is able to respond with just-in-time delivery of the right amount. The article compares the process to “controlled management” within a city. It guarantees that “just the right number of mucins or insulin is released based on bodily needs,” one of the researchers said.

These three reports admired the good design of the cellular systems and strategies involved, having nothing to say about evolution. Another story from the University of Munich, though, explored reasons for bitter taste receptors outside the oral cavity, but wandered off the route into Darwin fantasyland along the way. The article speculated that “endogenous substances may have influenced the evolution of bitter taste receptors,” etc. Gong!

Scientists, if you are reading this, please leave this kind of storytelling on the cutting room floor. Just tell us what is going on and how it works. It must be working well, because humans can live with all these cells performing their functions for over a century. Remember Paul Nelson’s Rule: if something works, it’s not happening by accident.

If this much detail goes into every one of the trillions of cells in our bodies, and extends up into the tissues, then the organs, then the organ systems, then the whole body, consider the implications. It means we were designed for a purpose. Do you have a purpose in life other than merely existing? Our heart beats to pump blood around the body, but what is the blood for, if not for a purpose beyond the circulatory system? Our lungs take in oxygen not just for respiration but for that system to perform a larger purpose. Mucins keep our airways clean for more than just cleanliness. Our neurons deliver proteins across synapses not just as idle activity, but to help us think about why we are here on this planet. Discovering our purpose brings fulfillment, gratitude and joy. Are you searching for your purpose? Start here and follow the signs.