Sensitization of Dictyostelium chemotaxis by phosphoinositide-3-kinase-mediated self-organizing signalling patches.

摘要: The leading edge of Dictyostelium cells in chemoattractant gradients can be visualized using green fluorescent protein (GFP) tagged to the pleckstrin-homology (PH) domain cytosolic regulator adenylyl cyclase (CRAC), which presumable binds phosphatidylinositol-(3,4,5)triphosphate [PtdIns(3,4,5)P3]. Uniform cyclic AMP (cAMP) concentrations induce persistent translocation PHCrac-GFP from cytosol multiple patches, are similar single patch at a cAMP gradient. We show that determines probability formation (half-maximal effect 0.5 nM cAMP) but not size, lifetime or intensity indicating patches self-organizing structures. A pseudopod is extended area cell with about 10 seconds after formation. Cells treated F-actin inhibitor latrunculin round without pseudopodia; uniform still induces localized PHCrac-GFP. Inhibition phosphoinositide-3-kinase (PI3K) activity LY294002 inhibits and chemotaxis towards nanomolar has no higher concentrations. Thus, very low serve as spatial cue for formation, enhances sensitivity amplitude chemotactic movement.