FIGURE 4.

Serine 264 of mouse TRESK is phosphorylated in vitro by Xenopus oocyte cytosol and protein kinase A. A, TRESKloop-H₈ proteins were phosphorylated with Xenopus oocyte cytosol in the presence of [γ-³²P]ATP. The mutant proteins contained only the serines indicated by the numbers above the lanes. The upper panel shows the SDS-PAGE gel stained with Coomassie Blue, whereas the autoradiogram of the same gel is on the lower panel. wt, wild type. B, a similar experiment as in A was performed with PKA (note that the protein containing only serine 264 was phosphorylated by both the cytosol and PKA).