|
|
|
|
|
|
|
|
|||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
|
Fig. 5. Proposed model of the effects of a stable rear of the cell on chemotaxis, cell-cell contact and cell streaming. (A) The strong spatiotemporal gradient at the rising flank of a cAMP wave induces a dominant pseudopod in both wild-type and gc-null cells. Wild-type cells suppress pseudopod formation in the posterior half of the cell. gc-null cells have an increased number of lateral pseudopodia, but their contribution to cell movement is relatively small during this phase. During the second half of the wave, wild-type cells maintain their polarized cell shape and extend pseudopodia only in the front. In the absence of a gradient-induced dominant pseudopod, the increased number of lateral pseudopodia in gc-null cells lead to a rapid decrease of directional cell migration during the second half of the cAMP wave. (B) The polarity of wild-type cells that is acquired during the first half of the wave results in a persistent orientation towards the aggregation centre in the second half of the wave. By contrast, gc-null cells, which do not properly polarize, lack the orientation towards the aggregation centre during the back of the wave. This decreased orientation leads to movement in apparently random directions and an increased tendency to break out of cell streams.
|
