Tropomyosins

Part of speech: noun

Definitions

1. Several fibrous proteins found in muscle cells that help control how actin and myosin interact during contraction
2. Proteins that wrap along the actin filaments of muscle tissue and govern when the muscle is able to contract
3. Regulatory muscle proteins that block or expose binding sites on actin, thereby switching muscle contraction on and off

Etymology: Tropomyosins are the plural of tropomyosin, a protein found in muscle and other cells. Its name is built from two parts. The second, "myosin," is the name of the protein that drives muscle contraction. The first comes from Ancient Greek "trópos," meaning "turn." The name points to what the protein does: it sits along the thin filaments of muscle and turns on or off the interaction between actin and myosin, so the contraction can begin or stop. Because the word is a compound of a Greek element and an existing scientific name, it is a technical coinage rather than an old word that drifted into science. Its meaning is fixed by its role in biology, so the Greek sense of "turn" is preserved in the name rather than in everyday use.