Definition of External Regulators in Biology

Regulators

• According to a 2004 press release issued by the Salk Institute for Biological Sciences, regulators are proteins that guide a cell to grow, replicate or perform an action. For example, the Salk Institute has discovered one such protein that switches stem cells on or off in the human brain.

Internal and External

• There are two main types of regulators: internal regulators and external regulators. Internal regulators are proteins found exclusively in a cell. Therefore, cellular action from an internal regulator is only performed when the internal proteins react in a certain way. External regulators, however, are proteins that come from outside the cell. These proteins serve as messages that dictate what the cell must do.

Importance

• External regulators are unique because the proteins come as outside messages. The proteins are usually from hormonal and cellular feedback, giving the cell a new set of instructions. The most common orders from these external regulator proteins are to expand or slow down the cell cycle. The cell cycle is the replication process of cells. When more cells are needed, such as when fighting an infection, the external regulators tell immune cells (e.g., white blood cells) to make more of themselves.

Danger

• Protein errors, such as those due to genetic abnormalities or carcinogens, may result in cancerous behavior in a cell. This is because the cell's external regulators keep telling it to expand and replicate when it is not needed. This is essentially the nature of cancer--too many external regulators telling cells to expand to a point where tissue and other cells are damaged.