Sequence comparisons were performed using Sequencher software and publicly available Clustal W alignment algorithms

ants at the sites where F-actin projections emerge, which MedChemExpress SB 743921 suggests that spontaneous cell polarity would result from the stochastic activation of the guidance pathway G-protein-independent guidance pathways. We observed that PTEN was localized spontaneously at the rear edge in WT STA cells, and PI3K-dependent F-actin polymerization occurred at both the leading edge and at the rear edge. The elongation pattern indicated that the cells amplify shallow gradients of spontaneously produced PIP3 and maintain cell polarity through PI3K and PTEN. Moreover, the switching of ordered patterns suggests that cells stochastically choose one of the three ordered patterns and change it to another pattern in order to ensure overall random exploration during spontaneous cell migration. In contrast, chemotactic cells dominantly select the elongation pattern due to signals from G-proteins and then move toward the source of the chemoattractant by coordinating cell movement with the selected elongation pattern. Hence, cell polarity in chemotaxis could be considered as the property that cells dominantly choose an elongation pattern. Recent studies have shown that mutants lacking PI3K and/or PTEN do not sustain a polarized cell shape but can exhibit precise chemotaxis. Although cell polarity that is sustained by PI3K and PTEN in chemotaxis could be related to the elongation pattern of cell shape, neither the cell polarity nor the elongation pattern may be necessary for chemotaxis. Biological function of the transition of ordered patterns of cell shape We observed that the ordered patterns of cell shape stochastically transit from one pattern to another. This stochastic transition could add randomness to the motion of Dictyostelium. In terms of the advantage of randomness, we note similarities between the stochastic change of 9776380 flagella rotations of bacteria and the stochastic transition of ordered patterns of Dictyostelium cells. Motile bacteria such as Escherichia coli have flagella that are rotating structures driven by the proton motive force. Although Dictyostelium and E coli do not use identical locomotory apparatus, both forage with the aid of stochastically switching between two characteristic states, a fairly straight motion and a turning motion. For the fairly straight motion, bacteria rotate flagella in a clock-wise manner, and Dictyostelium cells maintain the elongation pattern of cell shape for at least 10 min. Moreover, for the turning motion, bacteria tumble by counterclockwise rotation of flagella, and Dictyostelium cells change into the rotation or oscillation pattern that lasts the order of 1020 min. Ordered Shape and Motion Stochastic switching of these ordered patterns allows cells to do overall random exploration. Regarding the efficiency of searching behavior, Li 9776380 et al. have conducted the numerical simulation of the amoeboid motion in which a cell finely directs the motion with a persistent time of approximately 9 min. By comparing to the random walk, they found that the fairly straight motion of 9 min in the amoeboid motion allows cells to cover more area in a given time. This non-random motion results in the 1.6 to 2.4 fold increase of the efficiency greater than random walk. In our study, the coordination of the ordered patterns with cell movement suggests that the ordered patterns of cell shape attribute to the non-random motion in foraging behavior, e.g., the straight motion directed by the elongation pattern could realize the fairly str