Tropomodulins are proteins widely expressed in all complex animals that help to regulate the shape of cells by modifying the cytoskeletal filament actin. C. elegans worms lacking the tropomodulin TMD-1 show defects in development of the excretory cell, which acts as a kidney for the worm. The excretory cell extends four canals out from the cell body so that the entire cell looks like a great letter H stretching the length of the worm. In tmd-1 mutants, canals extend partially or not at all, and develop a dramatic crinkled appearance. The mechanism for this interference is unknown; however several possibilities are being explored. Excretory canals are often affected by mutations in genes, also needed in neuronal axon guidance. Knocking down one of these guidance proteins, MIG-10, produced a similar phenotype to that of the tmd-1 mutants. However, further experiments did not uncover any neuronal guidance defects in tmd-1 mutants. Instead, it is more likely that TMD-1 is essential for vesicle trafficking within the excretory canal. In this function TMD-1 may facilitate canal extension by providing membrane components to the growing canal tips. Insight into tropomodulin’s role in single-celled tube formation can further our understanding of how these tubes form in many organisms.
"Characterizing the Role of the Actin-binding Protein, TMD-1/tropomodulin in C. elegans Excretory Cell Morphogenesis,"
Proceedings of GREAT Day: Vol. 2013, Article 9.
Available at: https://knightscholar.geneseo.edu/proceedings-of-great-day/vol2013/iss1/9