ADF / cofilins are a family of proteins that interact with actin , an important cytoskeleton protein. There are three cofilin genes in the human and mouse genome, which are characterized by high evolutionary conservatism:
- CFL1 encoding cofilin-1 (alternative name is non-muscular, English non-muscular cofilin, n-cofilin )
- CFL2 encoding cofilin-2 (alternative name is muscle cofilin, English m-cofilin )
- DSTN , an encoding Destrin , also known as ADF , Eng. actin depolymerizing factor - “actin depolymerization factor”
Cofilin and other proteins of this group regulate the assembly and disassembly of actin filaments [1] . Cofilin belongs to the family of ADP-cofilin proteins; has 70% homology with the sequence of ADP (actin depolymerizing factor, ADF), which actually determines its belonging to ADP-cofilins, a family of small ADP-binding proteins [2] . Cofilin and other proteins of this group regulate the assembly and disassembly of actin filaments. It can bind both with actin monomers (G-actin) and with actin polymer (F-actin) [3] . Cofilin can depolymese “-” - the end of the actin filament, thereby preventing their assembly. Cofilin can break actin filaments into large fragments. These monomers can move and recover to form filaments with ATP cleavage.
Content
- 1 Functions
- 2 Associations with Arp2 / 3 complex
- 3 notes
- 4 References
Functions
Cofilin is an actin-binding factor found in all cells that is necessary for the reorganization of actin filaments. Representatives of the ADP / cofilin family bind G-actin monomers and depolymerize actin filaments using two mechanisms: rupture [4] and increase the rate of actin monomer separation from the active end [5] . For the effective functioning of cofilin, tropomyosin-free “old” actin filaments, in which it is associated with ADP / ADP + F, and an appropriate pH level are required. In the presence of available ATP-G-actin, cofilin accelerates the actin polymerization by breaking actin filaments (providing free ends for polymerization and promoting activation of the Arp2 / 3 complex) [6] . The long-term effect of cofilin in vivo is that it processes old ADP + F-actin, helping to maintain a pool of free ATP-G-actin, providing cytoskeletal remodeling and cell motility. The activity of cofilin depends on pH and is regulated by phosphorylation, as well as with the participation of phosphoinositides [3] .
Associations with Arp2 / 3 complex
The Arp2 / 3 complex and cofilin work together to reorganize the cytoskeleton actin filaments. The Arp2 / 3 complex binds to ATP-F-actin on the side of the growing end of the filament, causing the nucleation (nucleation) of a new F-actin filament [6] , and cofilin initiates the depolymerization that occurs after dissociation of the filament from the Arp2 / 3 complex [1] . They also work together to reorganize microtubules in order to transfer more proteins within the vesicles to continue filament growth [7] .
Cofilin can also bind to proteins such as myosin , tropomyosin , α-actinin , gelsolin and scruin . These proteins compete with cofilin for binding of actin filaments [2] .
Notes
- ↑ 1 2 Cooper, GM and RE Hausman. The Cell: A Molecular Approach, 3rd ed. Washington DC: ASM Press 2004 pp. 436-440.
- ↑ 1 2 McGough, A., Pope, B., Chiu, W., and A. Weeds. (1997) The Journal of Cell Biology 138: 771-781.
- ↑ 1 2 Lappalainen, P. and DG Drubin (1997) Nature 388: 77-82.
- ↑ Ichetovkin I., Han J., Pang KM, Knecht DA, Condeelis JS (2000) Cell Motility and Cytoskeleton. 45 (4): 293-306.
- ↑ Carlier, MF, Laurent, V., Santoloni, J., Melki, R., Didry, D., Xia, GX, Hong, Y., Chua, NH, and D. Pantaloni (1997) The Journal of Cell Biology 136: 1307-1323.
- ↑ 1 2 Ichetovkin I., Grant W., Condeelis J. (2002) Current Biology 12 (1): 79-84.
- ↑ Svitkina, TM, and GG Borisy. (1999) The Journal of Cell Biology 145: 1009-1026.
Links
- ADF / Cofilin Protein - Medbiol.ru