Dictyostelium Cells Migrate Similarly on Surfaces of Varying Chemical Composition

Abstract

During cell migration, cell-substrate binding is required for pseudopod anchoring to move the cell forward, yet the interactions with the substrate must be sufficiently weak to allow parts of the cell to de-adhere in a controlled manner during typical protrusion/retraction cycles. Mammalian cells actively control cell-substrate binding and respond to extracellular conditions with localized integrin-containing focal adhesions mediating mechanotransduction. We asked whether mechanotransduction also occurs during non-integrin mediated migration by examining the motion of the social amoeba Dictyostelium discoideum, which is thought to bind non-specifically to surfaces. We discovered that Dictyostelium cells are able to regulate forces generated by the actomyosin cortex to maintain optimal cell-surface contact area and adhesion on surfaces of various chemical composition and that individual cells migrate with similar speed and contact area on the different surfaces. In contrast, during collective migration, as observed in wound healing and metastasis, the balance between surface forces and protrusive forces is altered. We found that Dictyostelium collective migration dynamics are strongly affected when cells are plated on different surfaces. These results suggest that the presence of cell-cell contacts, which appear as Dictyostelium cells enter development, alter the mechanism cells use to migrate on surfaces of varying composition.

The interplay of cell–cell and cell–substrate adhesion in collective cell migration

“…Bright-field and IRM images of AX3 cells on glass are shown in figure 1a. As we previously reported [14], cells partially adhere to glass surfaces. (Regions of adherence appear dark in IRM images.…”

“…For example, it has been shown in vivo that fibre-like structures in the ECM can provide directional guidance and direct multicellular streams [3,9]. We previously showed that cell-surface adhesion can also affect collective migration: D. discoideum cells exhibit different collective migration patterns on surfaces with different inherent adhesivities [14]. However, it is not well understood how cellsurface adhesion affects collective migration, or how touching cells achieve highly coordinated motion.…”

Shear force-based genetic screen reveals negative regulators of cell adhesion and protrusive activity

“…Dictyostelium cells are not known to form stable focal adhesions although they express homologs of talin, vinculin, and paxillin which localize to the basal surface in puncta with F-actin (1,(50)(51)(52). Because Dictyostelium cells need to migrate over a variety of surfaces in their natural environments, their substrate adhesion is thought to be largely nonspecific (53)(54)(55). For the seven validated mutants reported there was a strong correlation between flatness and adhesion.…”

Adhesion strategies ofDictyostelium discoideum– a force spectroscopy study

“…based on fluorescence and RICM studies. 81,83 They could show that the equilibrium of protrusive forces and adhesion forces allows D.d. to adhere and maintain shape on a multitude of substrates, while multicellular development and the occurrence of cell-cell contacts significantly interfere with this equilibrium.…”