The Dictyostelium prestalk inducer differentiation-inducing factor-1 (DIF-1) triggers unexpectedly complex global phosphorylation changes.
Bottom Line: The results also provide evidence that the Ca(2+)/calmodulin-dependent phosphatase calcineurin plays a role in DIF-1 signaling to the DimB prestalk transcription factor.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.All MS data are available via ProteomeXchange with identifier PXD001555.
Affiliation: College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.Show MeSH
Mentions: Surprisingly, many of the DIF-1–regulated phosphorylation sites lie in cAMP signaling pathways (Figure 4). Extracellular cAMP signals are perceived and transferred into the cell by cAR1. Binding of extracellular cAMP to cAR1 stimulates many signaling events and phosphorylation at multiple residues on its cytoplasmic tail (Hereld et al., 1994). We identify 10 DIF-1–regulated phosphorylation sites on cAR1; eight are the same residues phosphorylated in response to cAMP binding (Figure 5A). Four of the five class I sites (S299, S303, S304, S324, and S325) show a major and consistent dephosphorylation (Figure 5B), contrasting with the phosphorylation that occurs in response to cAMP.
Affiliation: College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.