Possibly due to high tissue density or Reversine adhesiveness. However, macrophages were able to respond to a wound signal while still respecting the tissue barriers, by taking a longer path through areas that were easier to invade. How the two contradicting signals are balanced in this example is currently unknown. Our predictions could easily be tested by creating maze-like geometries and allowing cells to migrate therein. In fact, two very recent reports have shown how this can be done. In, a simple set of path bifurcations were presented to neutrophils moving under a chemokine gradient. The cells were able to successfully choose the short path. However, this study did not investigate the case where the local chemical cues are insufficient for proper navigation, and the cells indeed followed the steeper gradient. The “frustrated�?situation where this simple strategy would lead to trapping is in our opinion more generic. In, paths were etched in a collagen matrix as a way of creating a more faithful in vitro analog of extracellular matrix ; the authors then studied the migratory capabilities of cancer cells in their construct. Again, the questions of primary concern here were not specifically addressed, as in this case there was no controlled gradient providing directional information. To summarize, we studied amoeboid motion using a computational model for cellular navigation. Our model shows that cells moving in this manner can avoid being trapped at small but not large obstacles. We then demonstrated that a simple marker strategy can improve navigation in complex terrains. This realization provides important clues into mechanisms that might be employed by real cells�?migration in complex environments as well as suggests that location memory should be incorporated into robotic navigation designs. The results can be used in the study of mammalian cell migration and cancer metastasis. Such low and medium-resolution structures are nonetheless informative given that they reveal the arrangement of transmembrane alpha-helices and other secondary structure elements within membrane proteins as well as their supramolecular assembly. Expression systems currently used to produce membrane proteins for structural studies include bacteria, yeast, insect cells, cell-free approaches and mammalian cells. Each system has its advantages but none is optimal for all types of membrane proteins. The Xenopus laevis oocyte expression system could represent one exception given that it has been shown to allow for the robust expression of many functional mammalian channels and solute carriers. This system owes its success to its ability to translate heterologous mRNA and cDNA-derived cRNA efficiently, and to provide most of the necessary cofactors required for the functional expression of recombinant proteins at the cell surface. Due to technical and methodological limitations.