In an interesting paper in last week’s PNAS, Yingchun Wang and colleagues have done something interesting: dissected apart the pseudopodium from the remainder of the cell body in chemotactic cells, for proteomic analysis. This is extremely useful, as it may help to characterize the polarized spatial distributions of multiple signaling networks. And there’s quite a bit of evidence already to suggest that the leading/front edge, or pseudopod, of migrating cells is a functional subdomain, with separate mechanisms at work to turn specific cell behaviors on or off.
Wang et al. used L-[alpha]-lysophosphatidic acid (LPA) gradients in a modified trans-well assay (using microporous membranes), to “trap” the pseudopodia away from the cell body. Subsequent mass spectrometry identified the protein components.