Short- and long-term memory of moving amoeboid cells
Fig 5
Cells memorize the polarity axis by pseudopod activity and sGC activity in the front.
a. Wild-type cells expressing LimE-GFP (detecting F-actin) and myosin II-RFP. A de novo pseudopod can generate a new polarity axis. b. Pseudopod activity in the front before and after the extension of a de novo pseudopod. Measured were the pseudopod frequency (in 1/s), pseudopod growth rate (in μm/s) and their product. Data are the means and SEM of 98 de novo pseudopods. ***, significantly different from the data value for all pseudopods at P<0.01; *, significant at P<0.05. c. Localization of sGC guanylyl cyclase. The left panel shows enrichment of sGC-GFP in the F-actin cortex of protrusion. This cortical localization is lost upon deletion of the N-terminus of sGC [29], or by addition of the F-actin polymerization inhibitor Latrunculin A (LatA). d. basal in vivo cGMP levels of gc-null cells expressing full length sGC or the N-terminal deletion mutant ΔN-sGC, and basal cGMP and cAMP levels of wild-type AX3 cells in the absence or presence of 10 μM LatA. Data are the means and SD of four determinations in triplicate. e. Localization of Rap1-GFP (using Ral-GDS-GFP and cytosolic-RFP [22]) and myosin II (with myosin II-GFP in cells under agar [33]). f. Fluorescent intensity of Ral-GDS-GFP minus cytosolic-RFP (Ψ) representing Rap1-GTP levels at the boundary of the cell (mean and SEM of 10 cells). Fluorescent intensity of myosin II-GFP in the cortex relative to the intensity in the cytosol (mean and SEM of 5 cells).