Tyrosine Phosphorylation-Mediated Signaling Pathways in Dictyostelium

Figure 3

Four hypertonic stress responses in Dictyostelium. Cells stressed in hypertonic solution exhibit tyrosine phosphorylation of actin, myosin II heavy chain phosphorylation, activation of a group of genes by STATc, and alteration of intracellular pH. The elevation of the intracellular cGMP level induces activation of the myosin heavy chain kinase and thus remodels the cellular architecture of myosin II organization. The activation of STATc by a Tyrosine Kinase Like is also mediated through increased cytosolic cGMP. The mechanisms of actin tyrosine phosphorylation and intracellular pH alteration need further investigation. Solid arrows are supported by direct evidence, while dashed arrows are suggested by circumstantial evidence.