Isoform 4 of Dynactin subunit 1

Dynactin subunit 1 (DCTN1) isoform 4 is a large cytoplasmic protein (138.75 kDa) that functions as a component of the dynactin complex, a regulatory cofactor essential for dynein-mediated microtubule-based transport (UniProt: Q14203-4). The dynactin complex plays critical roles in intracellular cargo transport, organelle positioning, and cell division across diverse cellular contexts.

DCTN1 is widely expressed and dysfunction has been associated with neurodegenerative conditions affecting motor neuron and axonal transport systems. The protein's role in cytoplasmic dynein regulation makes it relevant to neuronal homeostasis and axonal integrity maintenance.

In Alzheimer's disease, DCTN1 isoform 4 shows increased abundance in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.606 (Chaparral AD proteomics). This upregulation was detected across subcellular fractions in TMT-labeled quantitative proteomics analysis of human AD brain, suggesting potential compensatory dynein-mediated transport responses or altered cytoskeletal dynamics in AD pathology.