actin

¹

[ ak-tuhn ]

noun

, Biochemistry.

1. a globulin that is present in muscle plasma and that in connection with myosin plays an important role in muscle contraction.

actin-

²

1. variant of actino- before a vowel:

   actinism.

actin

/ ˈæktɪn /

noun

1. a protein that participates in many kinds of cell movement, including muscle contraction, during which it interacts with filaments of a second protein, myosin

actin

/ ăk′tĭn /

1. A protein found in all eukaryotic cells, forming filaments that make up a main component of the cell's supporting matrix or cytoskeleton . Actin and the protein myosin together make up the contractile units (called sarcomeres ) of skeletal muscle fibers.

Word History and Origins

Origin of actin¹

1940–45; perhaps act + -in ²

Word History and Origins

Origin of actin¹

C20: from act + -in

Example Sentences

"Oi don't loike th' way he is actin', Frankie," whispered Barney.

From Project Gutenberg

Can't you hear millions spoke of without actin' like a blasted whistlin' buoy?

From Project Gutenberg

And when he quit he went off toward home, slappin' his fists together and actin' as if he didn't see the road across his bows.

From Project Gutenberg

Ed was actin at Niblo's Garding, which looks considerable more like a parster than a garding, but let that pars.

From Project Gutenberg

I don't know what them skunks think they can do, actin' in this way.

From Project Gutenberg