Scientists have found a protein that causes albinism.
Biologists from brown University in the US found that the activity of the protein TPC2 contributes to reducing the production of melanin. The discovery not only helps scientists to understand what influences the color of the eyes, skin and hair of a person, but will bring them closer to unraveling the origin of albinism.
In late 2014 the researchers found that melanosomes (organelles that contain melanin and some other pigments) use ion channels OCA2, one of the varieties of transport proteins to increase the production of melanin. A new study showed that TPC2 is a “counterweight” OCA2.
Before opening it was known that the TPC2 gene is associated with pigmentation. In particular, two mutations of this gene influenced the appearance of the inhabitants of Northern Europe, light skin and hair. However, the mechanism of action of protein on pigmentation was unknown. The protein encoded by the TPC2 gene, removes positive ions of sodium from the melanosomes. Because of this, the environment inside organelles becomes more acidic and the enzyme regulating the melanin production, is suppressed. Elena Oancea, the study’s lead author, commented: “the Presence of several ion channels in the cell allows you to adjust the pH (acid-alkaline balance) depending on conditions”.
In the study, biologists have studied cells of mouse skin cells and eyes of frogs, as they melanosome larger than in human cells. Scientists noticed electrical activity in the membrane of organelles, corresponding to the flow of positive ions.
When researchers blocked TPC-channels, the current is stopped. They also noted that cells with reduced levels of protein TPC2 have more melanin. “Because TPC2 is a negative regulator of pigmentation, TPC2 blockers can be used to compensate for defects in pigmentation,” explained Oancea. The results of the study can help in the search for a cure for albinism.
