Figure 8.

In vitro phosphorylation of NF-M side-arm and the MPR domain of NF-H side-arm with p42MAPK and SAPK1b. Left panels are phosphorylation by p42MAPK, and right panels are phosphorylation using SAPK1b. The top panels are the autoradiographs, and the bottom panels are the corresponding Coomassie-stained gels. RM are reaction mixes only without GST/NF-M/NF-H substrates; GST are reaction mixes with GST substrate; NF-M are reaction mixes with NF-M substrate; and NF-H are reaction mixes with the NF-H MPR domain substrate. Minus and plus signs refer to the absence or inclusion of kinases in the reaction mixes. The lower molecular mass species seen in tracks containing the NF-M side-arm domain are probably proteolytic degradation products since many of these react with NF-M antibodies. We were unable to inhibit this proteolysis despite using cocktails of protease inhibitors.