Cytoplasmic dynein is a well-defined conserved motor protein complex that moves cargo along microtubules, performing essential functions mainly related to intracellular transport and cell division. Investigations into the different dynein subunits reveal that these components possess multiple essential roles independent of the dynein complex. Mutations in the dynein complex have been linked to several neurodegenerative disorders and cancer; therefore, understanding dynein or its subunits’ function is essential for identifying novel therapeutic targets in these diseases.

The primary objective of this PhD study was to elucidate novel functions of dynein light chain 1 (DLC-1) and to investigate its regulation, utilizing the model organism Caenorhabditis elegans.

In Paper I, DLC-1 was found to play a novel role in maintaining the appropriate plasma membrane localization of the engulfment receptor CED-1. These investigations further revealed previously unknown functions for CED-6 and CED-7 in CED-1 localization. We suggest that the mechanism relies on endocytosis, as DLC-1 had been previously shown to participate in endocytic uptake, and as CED-6 and CED-7 function redundantly with clathrin and adaptors of clathrin-mediated endocytosis.

In Paper II, a novel regulator of DLC-1, termed Suppressor of Aph-One (SAO-1), was identified. This study presents evidence that SAO-1 specifically regulates DLC-1 expression in the germline cytoplasm, thereby protecting DLC-1 from proteasomal degradation. However, the precise molecular mechanisms underlying this regulation have yet to be fully elucidated.