Question

What protein complex links dynein to cargo?

Answer 1

The protein complex that links dynein to cargo is Dynactin. Dynactin is a multi-subunit complex that was first identified as a biochemical activity required for dynein-driven vesicle movement along microtubules. Dynactin is a large protein complex (1 MDa), composed of more than 20 subunits per complex. Dynactin is a large protein complex linked to the retrograde motor dynein, and it is thought to link the motor to its cargo and/or increase the processivity of the motor. Dynein is largely inactive in the cytoplasm and that a variety of adapter proteins activate processive motility by linking dynactin to dynein only when the motor is bound to its proper cargo. A diverse array of cargoes including membranous organelles, synaptic vesicle precursors, signaling molecules, growth factors, protein complexes, cytoskeletal components, and even the sodium and potassium channels required for action potential propagation are actively transported from their site of synthesis in the cell body through the axoplasm to intracellular target sites in the axon and synapse.

Functional aspects of Dynactin with respect to Dynein are as follows;

1. Dynactin acts as a cargo adaptor.

2. It acts as a processivity enhancer.

3. Dynactin binds microtubules and is involved in cellular and axonal transport.

4. Dynein/dynactin complex could play a role in neurodegeneration.

5. The dynein–dynactin complex is a critical component of fast retrograde transport of vesicles and organelles.