Dynein

Part of speech: noun

Definitions

1. A large motor protein that walks along microtubules inside cells, using energy from ATP to move cargo and drive movements such as cilia beating
2. A protein complex that converts chemical energy into mechanical movement by traveling along the microtubule tracks found within cells
3. An enzyme-like molecular motor responsible for transporting materials and powering flagella and cilia by moving along cellular microtubules

Etymology: Dynein is a biology coinage, so its story is one of deliberate construction rather than long drift. It is built from "dyne," a unit of force in the centimetre-gram-second system, and the "-in" ending that chemists attach to proteins. The unit itself comes from the Ancient Greek "dynamis," meaning "force" or "power," the same root behind "dynamic" and "dynamite." The surprising link is that a unit named for the Greek idea of power ended up naming a molecular machine. Cells use dynein to move cargo along microtubules and to make cilia and flagella beat, so the protein really is a force-generator at the smallest scale. The word thus carries its Greek ancestor's sense of force into a field where the Greeks could never have imagined it.