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: We identified two closely spaced phosphorylation sites on PKBR1 (T442 and S449), both of which are dephosphorylated in response to DIF-1 (Figure 6A). Averaged temporal data for the class I site, S449, shows consistent dephosphorylation after DIF-1 treatment (Figure 6B). Nine PKBA/PKBR1 substrates have been identified (Kamimura et al., 2008; Liao et al., 2010; Tang et al., 2011), and, significantly, we identified class I phosphorylation sites in no fewer than four of these proteins (Figure 6, A and C): GacG, a RhoGAP; GefN, a RasGEF; PakA, an STE20-family, P21-activated protein kinase; and most, strikingly, SHAPS, which undergoes a 19-fold dephosphorylation (log2 ratio, −4.3) after just 1 min of DIF-1 treatment (Figure 6B).
Affiliation: College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.