Figure 3.

In vitro phosphorylation of truncated versions of ETR1. GST fusions with either ETR1(164–609) or ETR1(333–609) were examined for the ability to autophosphorylate. Both wild-type (WT) and the His-353–Gln (H) site-directed mutation of ETR1 were tested in each case, and an autoradiograph of the alkali-resistant phosphorylation is shown (³²P). Relative size of the phosphorylated proteins, as based on molecular mass standards, is indicated in kDa. After autoradiography, the presence of each fusion protein was confirmed by Western blot using a polyclonal antibody directed against GST (Ab).