DCTN1 and amyotrophic lateral sclerosis: Cytoplasmic dynein is a multi-subunit protein complex, with heavy chains having ATPase activity and interacting with light chains to generate the cargo-binding complex and binds to the microtubules to mediate retrograde transport.39,40 To achieve its full functional role, dynein requires dynactin, mutations in the largest subunit (dynactin-1 or DCTN-1) of which were previously linked to ALS.41