RAS

“RAS” stands for Rat Sarcoma—named after the rat sarcoma virus in which it was first discovered. In human biology, RAS refers to a family of genes (like HRAS, KRAS, and NRAS) that produce RAS proteins, which are small GTPases (enzymes that bind and hydrolyze GTP). These proteins are critical regulators of cell signaling, especially in the RAS/MAPK pathway.

What does RAS do?

RAS proteins act like molecular switches inside cells:

• When “on” (bound to GTP), they activate signaling pathways that promote cell growth, division, and survival.
• When “off” (bound to GDP), the signals stop.

This process is tightly regulated under normal conditions.

Why is RAS important in RASopathies?

Mutations in RAS or genes that regulate it lead to overactive signaling, even when it’s not supposed to happen. This causes cells to behave abnormally—leading to the developmental issues seen in RASopathies, or to uncontrolled cell growth in cancers.

So in short:

• RAS = Rat Sarcoma (original discovery name)
• Function = cell signaling control
• Problem = mutations cause overactive signaling → developmental disorders (RASopathies) or cancer

Want to see a visual or simple diagram of how the RAS/MAPK pathway works?