DEFINITION of 'Commercial'. Relating to commerce. In the investment field, the term commercial is generally used to refer to a trading entity engaged in business activities that are hedged by positions in the futures or options markets.
The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. When the receptor is activated, it triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin.
Basically it controls everything that happens inside the cell, it's like a boss of the cell. People also call it the brain of the cell. But, the nucleus does not control everything. There is one part the nucleus cannot control, it is the cell membrane. The cell membrane controls what gets in or out of the cell.