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ADF/cofilin is a family of actin-binding proteins which disassembles actin filaments. Three highly conserved and highly (70%-82%) identical genes belonging to this family have been described in humans and mice: * CFL1, coding for cofilin 1 (non-muscle, or n-cofilin) * CFL2, coding for cofilin 2 (found in muscle: m-cofilin) * DSTN, coding for destrin, also known as ADF or actin depolymerizing factor Actin-binding proteins regulate assembly and disassembly of actin filaments.〔Cooper, G. M. and R. E. Hausman. ''The Cell: A Molecular Approach,'' 3rd ed. Washington DC: ASM Press 2004 pp.436-440.〕 Cofilin, a member of the ADF/cofilin family is actually a protein with 70% sequence identity to ADF, making it part of the ADF/cofilin family of small ADP-binding proteins. 〔 〕 The protein binds to actin monomers and filaments, G actin and F actin, respectively. Cofilin causes depolymerization at the minus end of filaments, thereby preventing their reassembly. The protein is known to sever actin filaments by creating more positive ends on filament fragments.〔 Cofilin/ADF(destrin) is likely to sever F-actin without capping 〔 and prefers ADP-actin. These monomers can be recycled by profilin, activating monomers to go back into filament form again by an ADP-to-ATP exchange. ATP-actin is then available for assembly.〔 ==Structure== Cofilin binds monomeric (G-actin) and filamentous actin (F-actin). Its binding affinities are higher for ADP-actin over ADP-Pi and ATP-actin. Its binding changes the twist of F-actin. The structure of ADF was first characterized in 1980 by James Bamburg. Four actin histidines near the cofilin binding site may be needed for cofilin/actin interaction, but pH sensitivity alone may not be enough of an explanation for the levels of interaction encountered. Cofilin is accommodated in ADP-F actin because of increased flexibility in this form of actin. Binding by both cofilin and ADF(destrin) causes the crossover length of the filament to be reduced. Therefore, strains increase filament dynamics and the level of filament fragmentation observed.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「cofilin」の詳細全文を読む スポンサード リンク
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