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Dynactin or Dynein activator complex is a multi-subunit protein found in eukaryotic cells that aids in bidirectional intracellular transport by binding to dynein and kinesin-2 and linking them to the organelle or vesicle to be transported.〔 〕〔 〕 ==Structure and mechanism of action== Dynactin consists of many subunits of which the p150Glued protein (encoded by the DCTN1 gene) is the largest and has been found to be essential for function.〔 This structure of dynactin is highly conserved in vertebrates. There are three isoforms encoded by a single p150Glued gene.〔 〕 The dynactin complex visualized by deepetch electron microscopy appears as a short filament 37-nm in length, which resembles F-actin, plus a thinner, laterally oriented filament that terminates in two globular heads. The dynactin complex consists of three major structural domains: (1) sidearm-shoulder: DCTN1, DCTN2/dynamitin, DCTN3/p22/p24;(2)the Arp1 rod: Arp1/centractin, actin, CapZ; and (3) the pointed end complex: Actr10/Arp11, DCTN4/p62, DCTN5/p25, and DCTN6/p27. Dynactin interacts with dynein directly by the binding of dynein intermediate chains with p150Glued.〔 〕 DCTN2 (dynamitin) is also involved in anchoring microtubules to centrosomes and may play a role in synapse formation during brain development. DCTN4 (p62) binds directly to the Arp1 subunit of dynactin. Arp1 has been shown as the domain for dynactin binding to membrane vesicles (such as Golgi or late endosome) through its association with β-spectrin. The pointed end complex (PEC) has been shown to be involved in selective cargo binding. PEC subunits p62/DCTN4 and Arp11/Actr10 are essential for dynactin complex integrity and dynactin/dynein targeting to the nuclear envelope before mitosis. Dynactin p25/DCTN5 and p27/DCTN6 are not essential for dynactin complex integrity, but are required for early and recycling endosome transport during the interphase and regulation of the spindle assembly checkpoint in mitosis.〔 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「Dynactin」の詳細全文を読む スポンサード リンク
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