The residues on MAP kinase kinase-1 (MAPKK1) phosphorylated by MAP kinase in vitro have been identified as Thr-291 and Thr-385. Both threonines are phosphorylated in PC12 cells and the 32P-labelling of each residue increases after stimulation with nerve growth factor (NGF). The results establish that MAPKK1 is a physiological substrate for MAP kinase. The two active forms of MAPKK that are resolved by Mono Q chromatography of PC12 cell extracts are both phosphorylated at Thr-291 and Thr-385, demonstrating that neither species is the MAPKK2 isoform which lacks Thr-291.
Author(s):
Saito, Y., Gomez, N., Campbell, D. G., Ashworth, A., Marshall, C. J., Cohen, P.
PubMed:
8137910
Citation:
Saito, Y., Gomez, N., Campbell, D. G., Ashworth, A., Marshall, C. J., Cohen, P.
Saito, Y., Gomez, N., Campbell, D. G., Ashworth, A., Marshall, C. J., Cohen, P.
FEBS Lett
1994
341
119-24
PMID: 8137910