How is mucus formed in us and in other mammals?

Scientists have discovered that the protein that makes our saliva so slippery has been created over and over again from other proteins.

What do slime slugs and cute baby drool have to do with each other? Both contain protein musin. This is so useful that it has appeared in mammals many times during evolution from completely different proteins. This is evidenced by genetic research from the University of Buffalo (USA), that in science magazine science progress has been published.

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hair brush

Mucins have many functions, but the most well-known is that they cause the typical slip of body glue. This is necessary, for example, to allow food to slide smoothly through the esophagus into your stomach. It also acts as a protective barrier against pathogens.

Part of the myosin protein is made up of a constantly repeating chain of building blocks (amino acids), also known as repeat the name of the thing. These repeats have a kind of bump made up of sugar molecules. In fact, mucin is similar to a hairbrush. This typical shape gives the protein its slippery texture.

Surprise

The researchers, led by Omer Jokkomen and Stefan Ruhl, wanted to know how the structure of this hairbrush came about. They first took a closer look at a small saliva protein in humans called MUC7. This is the same volume of MUC10 found in mice. Were the proteins possibly ‘family’ to each other in the evolutionary tree? The somewhat disappointing answer: No.

After additional research, the researchers found a surprise: MUC10 is not similar to MUC7, but it is similar to PROL1, which is found in human tears. So while PROL1 is not mucin at all. The only difference between the two similar proteins is that MUC10 has the shape of a hairbrush, which is the typical characteristic of mucin.

This finding led Gokcumen, Ruhl and their colleagues to conclude that PROL1 was converted from non-mucin to mucin during mouse development. So kind of recycling. Such recycling may be necessary, for example, in cases of mucus deficiency in certain tissues or organs.

The next step was to compare the genes of several myosins to see if there were more instances of molecular recycling. This turned out to be the case: Of the 49 mammalian species examined, at least 15 were shown to have ‘reborn’ proteins such as myosin at some point in evolution.

very important

“A surprising discovery,” says infection researcher Karen Strijbis, a mucin specialist, of Utrecht University. Usually, genes arise from a copy of a gene with a similar function. The article convincingly demonstrates that new myosin genes have evolved in this way in many animal species.”

“The research shows that there is strong evolutionary pressure to give each animal species its own optimal mucus composition,” she continued. “A wonderful study confirms that mucus is extremely important for human and animal health.”

mucus buildup

The researchers note that they have conducted somewhat limited research. They only looked at certain parts of the mammal’s overall genetic package. So it is possible that there were more proteins converted to myosin. It might also be interesting to continue the research to see if this recycling process also occurs in other animals (non-mammals) that use mucus in their bodies – and there are very few of them.

Do we humans benefit from this knowledge? Yes, we now know that some proteins can be converted into mucus by the body under certain conditions. This mechanism may play a role in diseases in which mucus builds up, including cystic fibrosis, or tumors that grow from mucous cells. If this is indeed the case, it may provide scientists with starting points for new treatment approaches.

Sources: science progressAnd the University at Buffalo by EurekAlert!