Migratory responses in enucleated cells: The forces driving the locomotion movement of unicellular organisms.

Abstract

Locomotion movements are a fundamental characteristic of a variety of species, including prokaryotic and eukaryotic, that has a high impact on essential physiological and pathological processes. For decades, many different authors have focused on studying specific individual processes and their corresponding biomolecular components involved in cellular locomotion movements. Recently, we have shown that locomotion movements are regulated by integrative self-organized molecular processes operating at the systemic level. Here, to verify that said systemic behavior also exists in extreme critical physiological conditions such as those corresponding to enucleated cells, we carried out an extensive study with 200 enucleated cells (cytoplasts) belonging to the Amoeba proteus species. The migratory movements of both enucleated and nonenucleated cells (400 in total) have been individually studied in four different scenarios: in the absence of stimuli, under a galvanotactic field, in a chemotactic gradient, and under complex conditions such as simultaneous galvanotactic and chemotactic stimuli. All the experimental trajectories were analyzed using nonlinear quantitative metrics for individual cell trajectories. The results show that both nonenucleated amoebas and cytoplasts display the same type of dynamic migratory patterns. The locomotion displacements of enucleated cells are a consequence of complex self-organized molecular dynamics, modulated at a systemic-cytoplasmic level. We have also quantitatively detected that enucleation clearly affects the correlation times and the intensity of the migratory responses of cytoplasts. The fact that cytoplasts preserved the dynamic properties of their migratory trajectories when compared with nonenucleated cells suggests that nuclear activity has a minor role in regulating the locomotion displacements of cells.