A new microbiology study revealed the intricate workings behind cellular permissiveness in detail for the first time. Researchers managed to study the protein that is responsible for the way skin cells behave when they must take various chemicals from the outside environment without letting harmful substances get in.
 

The scientists working with the Department of Life Sciences at Imperial College London's Division of Molecular Biosciences, who carried on these experiments, identified a protein, dubbed microbacterium hydantoin permease (Mhp1), which plays a crucial role in changing the permeability of the cellular membrane to outside substances. Regularly, the oily membrane around skin cells prevents anything from passing through the three layers of the skin. The only way for foreign bodies to get through is as a result of lesions or burns in the skin itself.

 
Mhp1 is part of a wider class of proteins, known as "transporters", which play huge roles in all physiological processes taking place inside the human body. Digestion is possible because of them, as well as breathing, when the oxygen in the blood is carried by these proteins to every single organ. Cellular excretion is also carried out by these tiny transporters, which deposit all unneeded metabolic byproducts into the blood stream.
 

In order for the experiment to yield positive results, the protein was analyzed in various stages, so that researchers could analyze exactly what happened inside over various periods of time. Professor So Iwata, member of the College and author of the current study, used the Membrane Protein Laboratory (MPL) facility to study the amplified genetic expressions of Mph1, in cultures of E. coli bacteria. The main goal is to observe if and how the protein bound to hydantoin, a class of molecules closely resembling amino-acids.

 
"Our research has revealed the detailed molecular function of an important membrane protein. We now know how the protein facilitates the movement [of] hydantoin across the cell membrane without letting any other substances through at the same time," said Iwata, after the team discovered that Mph1 only opened for a little bit – as long as it took for hydantoin to move in - before closing and allowing the engulfed substance to move on.