Dynactin

[1][2] Dynactin was identified as an activity that allowed purified cytoplasmic dynein to move membrane vesicles along microtubules in vitro.

[4] The main features of dynactin were visualized by quick-freeze, deep-etch, rotary shadow electron microscopy.

It appears as a short filament, 37-nm in length, which resembles F-actin, plus a thinner, laterally oriented arm.

[5][6] Dynactin consists of three major structural domains: (1) sidearm-shoulder: DCTN1/p150Glued, DCTN2/p50/dynamitin, DCTN3/p24/p22;(2)the Arp1 filament: ACTR1A/Arp1/centractin, actin, CapZ; and (3) the pointed end complex: Actr10/Arp11, DCTN4/p62, DCTN5/p25, and DCTN6/p27.

[7] The C-termini of the p150Glued/DCTN1 dimer are embedded in the shoulder, whereas the N-terminal 1227 amino acids form the projecting arm.

[7] DCTN2 (dynamitin) is also involved in anchoring microtubules to centrosomes and may play a role in synapse formation during brain development.

[9] Arp1 has been suggested as the domain for dynactin binding to membrane vesicles (such as Golgi or late endosome) through its association with β-spectrin.

PEC subunits p62/DCTN4 and Arp11/Actr10 are essential for dynactin complex integrity and dynactin/dynein targeting to the nuclear envelope before mitosis.

[19] In addition, dynactin has been shown to play an essential role in maintaining nuclear position in Drosophila,[36] zebrafish[37] or in different fungi.