Actin Polymerization | G-Actins

Actin is a family of globular multi-functional proteins that form microfilaments.
An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells. It can be present as either a free monomer called G-actin (globular) or as part of a linear polymer microfilament called F-actin (filamentous), both of which are essential for such important cellular functions as the mobility and contraction of cells during cell division.
Nucleating factors are necessary to stimulate actin polymerization. One such nucleating factor is the Arp2/3 complex, which mimics a G-actin dimer in order to stimulate the nucleation (or formation of the first trimer) of monomeric G-actin. The Arp2/3 complex binds to actin filaments at 70 degrees to form new actin branches off existing actin filaments. Arp2/3-mediated nucleation is necessary for directed cell migration.Also, actin filaments themselves bind ATP, and hydrolysis of this ATP stimulates destabilization of the polymer.
The growth of actin filaments can be regulated by thymosin and profilin. Thymosin binds to G-actin to buffer the polymerizing process, while profilin binds to G-actin to exchange ADP for ATP, promoting the monomeric addition to the barbed, plus end of F-actin filaments.
F-actin is both strong and dynamic. Unlike other polymers, such as DNA, whose constituent elements are bound together with covalent bonds, the monomers of actin filaments are assembled by weaker bonds. The lateral bonds with neighbouring monomers resolve this anomaly, which in theory should weaken the structure as they can be broken by thermal agitation. In addition, the weak bonds give the advantage that the filament ends can easily release or incorporate monomers. This means that the filaments can be rapidly remodelled and can change cellular structure in response to an environmental stimulus. Which, along with the biochemical mechanism by which it is brought about is known as the "assembly dynamic.

[@ayeshajabeen6557]

in very short period of time has given a proper lecture.

[@hussainbiology]

thanks Ayesha for appreciation..Glad to know that it helps ✌️

[@azerty5590]

Really nice drawing, very clear and synthetic ! Thank you !

[@JYOtiRaNJanMANgaRaj]

Thank you 🙏

[@hussainbiology]

You’re welcome 😊

[@fannyvercherin4045]

Good job, that's help me a lot ! Plus thanks to have write the explication in the description box for people who don't understand English very well as me for example ;)

[@hussainbiology]

thanks for appreciation

[@krutikajoshi9667]

Easily explained with good presentation
Thank you 😊

[@hussainbiology]

Most welcome 😊

[@loneusman6504]

Doing good job......

[@Yolohipsteryolo]

Very good presentation template. Very clear. Thank you!

[@hussainbiology]

thanks for appreciation..Glad to know that it helps ✌️

[@ahaitshamsheikh9518]

Sir we know that minus end undergoes disassembly leading to treadmilling ,then how is the mechanism for minus end addition operational or how is this addition or dissociation operational at minus end.

[@drmksu38]

god gives some people Explanation talent thank you very much

[@hussainbiology]

Thanks Maryam for appreciation....Glad to know that it helps ✌️

[@mohdshahwaj5454]

Than you sir... ❤
Realy concepts clearing video....

[@hussainbiology]

thanks for appreciation

[@shirin6855]

Thank you so much!!!

[@hussainbiology]

You are welcome ✌️

[@chloedeckor2243]

Thankyou!💓

[@bonaparte6431]

Just as a note, it would be helpful to know which end of the G-actin monomer binds to the plus end and minus end respectively

[@hussainbiology]

thanks for appreciation..Glad it helps ✌️

[@shayekhabedin4462]

thanks so much!

[@hussainbiology]

You are welcome ✌️

[@Bossbabe448]

Actin can bind to both atp and adp

[@obrienconlan1]

You are a god

[@hussainbiology]

thanks buddy....Lots of love

[@madoaj653]

Hello there! Really nice videos. Could you please answer me I need to know if I can get these pictures that you are making

[@hussainbiology]

hi... For which video ???

[@pakkhan8391]

👍👍

[@shivanshsingh748]

polymerization mekanismas