Uniform cAMP Stimulation of Dictyostelium Cells Induces Localized Patches of Signal Transduction and Pseudopodia

Marten Postma, Jeroen Roelofs, Joachim Goedhart, Theodorus W.J. Gadella, Antonie J.W.G. Visser, Peter J.M. Van Haastert*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


The chemoattractant cAMP induces the translocation of cytosolic PH crac-GFP to the plasma membrane. PHcrac is a green fluorescent protein fused to a PH domain that presumably binds to phosphatydylinositol polyphosphates in the membrane. We determined the relative concentration of PHcrac-GFP in the cytosol and at different places along the cell boundary. In cells stimulated homogeneously with 1 μM cAMP we observed two distinct phases of PHcrac-GFP translocation. The first translocation is transient and occurs to nearly the entire boundary of the cell; the response is maximal at 6-8 s after stimulation and disappears after ∼20 s. A second translocation of PHcrac-GFP starts after ∼30 s and persists as long as cAMP remains present. Translocation during this second response occurs to small patches with radius of ∼4-5 μm, each covering ∼10% of the cell surface. Membrane patches of PH crac-GFP are both temporally and spatially closely associated with pseudopodia, which are extended at ∼10 s from the area with a PH crac-GFP patch. These signaling patches in pseudopodia of homogeneously stimulated cells resemble the single patch of PH crac-GFP at the leading edge of a cell in a gradient of cAMP, suggesting that PHcrac-GFP is a spatial cue for pseudopod formation also in uniform cAMP.

Original languageEnglish
Pages (from-to)5019-5027
Number of pages9
JournalMolecular Biology of the Cell
Issue number12
Publication statusPublished - 1 Dec 2003
Externally publishedYes


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