ac·tin

[ak-tuhn]
noun Biochemistry.
a globulin that is present in muscle plasma and that in connection with myosin plays an important role in muscle contraction.

Origin:
1940–45; perhaps act + -in2

Dictionary.com Unabridged

actin-

variant of actino- before a vowel: actinism.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2013.
Cite This Source Link To actin
00:10
Actin is always a great word to know.
So is interrobang. Does it mean:
the offspring of a zebra and a donkey.
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
Collins
World English Dictionary
actin (ˈæktɪn) [Click for IPA pronunciation guide]
 
n
a protein that participates in many kinds of cell movement, including muscle contraction, during which it interacts with filaments of a second protein, myosin
 
[C20: from act + -in]

actino- or (before a vowel) actin-
 
combining form
1.  indicating a radial structure: actinomorphic
2.  indicating radioactivity or radiation: actinometer
 
[from Greek aktino-, from aktis beam, ray]
 
actin- or (before a vowel) actin-
 
combining form
 
[from Greek aktino-, from aktis beam, ray]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
American Heritage
Medical Dictionary

actin ac·tin (āk'tĭn)
n.
One of the protein components found in muscle, existing as F-actin or G-actin, into which actomyosin can be split and which acts with myosin in muscle contraction.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
American Heritage
Science Dictionary
actin   (āk'tĭn)  Pronunciation Key 
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Example sentences
One of them causes a host protein called actin to clump together into long
  filaments.
These little guys crawl rather than swim, and the amazing thing is they have no
  actin.
One that churns out actin and myosin, which link up to form units that can
  expand and contract, will become a muscle cell.
Myosin is the molecular motor of muscle contraction: when it receives a
  particular chemical signal, it tugs on actin.
Copyright © 2013 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature
FAVORITES
RECENT