Glutathione S-transferase 4 is a putative DIF-binding protein that regulates the size of fruiting bodies in .

In the development of the cellular slime mold , two chlorinated compounds, the differentiation-inducing factors DIF-1 and DIF-2, play important roles in the regulation of both cell differentiation and chemotactic cell movement. However, the receptors of DIFs and the components of DIF signaling systems have not previously been elucidated. To identify the receptors for DIF-1 and DIF-2, we here performed DIF-conjugated affinity gel chromatography and liquid chromatography-tandem mass spectrometry and identified the glutathione S-transferase GST4 as a major DIF-binding protein. Knockout and overexpression mutants of ( and , respectively) formed fruiting bodies, but the fruiting bodies of cells were smaller than those of wild-type Ax2 cells, and those of cells were larger than those of Ax2 cells. Both chemotaxis regulation and stalk cell formation by DIFs in the mutants were similar to those of Ax2 cells. These results suggest that GST4 is a DIF-binding protein that regulates the sizes of cell aggregates and fruiting bodies in .