Please find below details of a paper just accepted for Mol Biol of the Cell (MBoC).

The Dictyostelium prestalk inducer Differentiation Inducing Factor-1 (DIF-1) triggers unexpectedly complex global phosphorylation changes

Chris Sugden*, Michael D. Urbaniak@, Tsuyoshi Araki* and Jeffrey G. Williams*

*From the College of Life Sciences, University of Dundee, Dow St., Dundee DD1 5EH, UK. @Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Bailrigg, Lancaster LA1 4YG, UK.

Address correspondence to: Jeffrey G. Williams ([log in to unmask])

Abbreviations: DIF-1, Differentiation Inducing Factor-1; SILAC, Stable Isotope Labeling by Amino Acids in Cell Culture

ABSTRACT

DIF-1 is a polyketide that induces Dictyoselium amoebae to differentiate as prestalk cells. We performed a global quantitative screen for phosphorylation changes that occur within the first minutes after addition of DIF-1 using a triple-label SILAC approach. This revealed a new world of DIF-1 controlled signalling: with changes in components of the MAPK and protein kinase-B signalling pathways, components of the actinomyosin cytoskeletal signalling networks and in a broad range of small GTPases and their regulators. The results also provide evidence that the Ca2+/calmodulin dependent phosphatase calcineurin plays a role in DIF-1 signalling to the DimB prestalk transcription factor. At the global level DIF-1 causes a major shift in the phosphorylation/dephosphorylation equilibrium towards net dephosphorylation. Interestingly, many of the sites that are dephosphorylated in response to DIF-1 are phosphorylated in response to extracellular cAMP signalling. This accords with studies that suggest an antagonism between the two inducers and also with the rapid dephosphorylation of the cAMP receptor that we observe in response to DIF-1 and with the known inhibitory effect of DIF-1 on chemotaxis to cAMP.



The University of Dundee is a registered Scottish Charity, No: SC015096