Talk:Microfilament

@ intro -- function

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This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Jmun002. Peer reviewers: Jmun002.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 04:03, 17 January 2022 (UTC)

Untitled
This needs to be simplified for laypeople learning biology. 69.248.145.222 (talk) 02:41, 26 November 2007 (UTC)

I think this whole actoclampin-stuff is highly speculative! —Preceding unsigned comment added by 193.174.111.250 (talk) 15:52, 14 February 2008 (UTC)

Stress fiber
Anyone knows the relation between microfilament and the term "stress fiber" (redirects here)? (130.243.161.203 (talk) 08:36, 14 October 2008 (UTC))
 * "Stress fibers are a specific cytoskeletal organization of actin monomers. These fibers are involved in cell shape a structural functions of the cell. Actin monomers form long polymers, which attach to the plasma membrane at focal adhesions. Contraction of the actin stress fibers allows the cell to exert tension on the substratum, an important part of controlling morphogenesis. Formation of stress fibers and focal adhesion complexes are a key regulatory event in cell growth and cell movement such as migration and invasion."--Tycho (talk) 15:56, 14 October 2008 (UTC)

Reply to 'Stress fiber': The above definition is incomplete, boarding on incorrect. Actin is a globular protein (~43 kDa). It polymerizes, forms into an ordered filament structure which has two protofilaments wrapping around each other, to form a single 'actin filament' also known as a 'microfilament'. Microfilament is an old term that originated before protein composition of the filaments was understood. Actin filament is the typically accepted terminology in scientific circles now. A stress fiber is a higher order structure. It is bundle of actin filaments, crosslinking proteins (proteins that bind two or more filaments together) and myosin II motors. The above definition sounds like contraction takes place in the actin filament itself. That is incorrect, the myosin motors in the stress fibers move, sliding actin filaments past one another, so the fiber can contract. The process of stress fiber dynamics is currently be rigorously studied and is not well understood. In order for contraction to generate forces the fibers must be anchored to something. Stess fibers can anchor to the cell memberane, and frequently the sites where this anchoring occurs are also connected to structures outside the cell (the matrix or some other substrate). These connection sites are called focal adhesion. Many proteins are required for proper focal adhesion production and maintenance. Contraction against these fixed external substrates is what allows the force generated by myosin motors and filament growth and rearrangement to move and reshape the cell. This is an extremely simple description of the process but, at least for now, adequate for this forum. —Preceding unsigned comment added by Limbodave81 (talk • contribs) 19:16, 24 March 2009 (UTC)

No mechanical force generated by treadmilling???
As far as I understand treadmilling involves elongation in the barbed end and shortening in the pointed-end, so that the filament in total moves. Since both processes are energetically favorable, this means force must be generated. This is also the explanation I've heard for one of the steps in cell crawling. The energy ultimately comes from the ATP hydrolization. See Alberts for all that.

related to this - for some reason the paragraph about ATP hydrolization appears in the article AFTER this section but it seems to me it should appear BEFORE.

Any comment? Dan Gluck (talk) 19:46, 9 September 2009 (UTC)

Since no comment arrived, I changed the section accordingly Dan Gluck (talk) 08:56, 26 September 2009 (UTC)

The information looks valid. All the references are given which does mean that it had been peer reviewed. Most of the references are from the science articles website, which is trust worthy. It does give a detailed information about Microfilament.

"''Actin treadmilling and actin gene regulation represent a linear signal transduction pathway in which actin treadmilling regulates actin gene transcription""  — Preceding unsigned comment added by Jmun002 (talk • contribs) 04:24, 21 November 2016 (UTC)

More information on "Actin acts as a track for myosin motor motility" is recommended. The explanation is well briefly written but, it should have a little more information about few more classes of myosin and how they are different. — Preceding unsigned comment added by Jmun002 (talk • contribs) 04:58, 21 November 2016 (UTC)