JNK1 is activated by phosphorylation of the canonical T183 and Y185 residues, modifications that are catalysed typically by the upstream eukaryotic kinases MKK4 and MKK7. Nonetheless, the exact sites at which the most abundant JNK variant, JNK1ß1, is further modified by MKK4 for phospho-regulation has not been previously investigated. Aiming to characterise the nature of JNK1ß1 phosphorylation by active MKK4 using mass spectrometry, a recognized yet uncharacterised phospho-site (S377) as well as two novel phospho-residues (T228 and S284) were identified. Interestingly, the identical sites were phosphorylated during overexpression of JNK1ß1 in E. coli, raising important questions that have significant implications for heterologous protein expression.
Reference:
Owen, G.R, Stoychev, S, Achilonu, I and Dirr, H.W. 2013. JNK1ß1 is phosphorylated during expression in E. coli and in vitro by MKK4 at three identical novel sites. Biochemical and Biophysical Research Communications, vol. 432(4), pp 683-688
Owen, G., Stoychev, S. H., Achilonu, I., & Dirr, H. (2013). JNK1ß1 is phosphorylated during expression in E. coli and in vitro by MKK4 at three identical novel sites. http://hdl.handle.net/10204/7520
Owen, GR, Stoyan H Stoychev, I Achilonu, and HW Dirr "JNK1ß1 is phosphorylated during expression in E. coli and in vitro by MKK4 at three identical novel sites." (2013) http://hdl.handle.net/10204/7520
Owen G, Stoychev SH, Achilonu I, Dirr H. JNK1ß1 is phosphorylated during expression in E. coli and in vitro by MKK4 at three identical novel sites. 2013; http://hdl.handle.net/10204/7520.
Copyright: 2013 Elsevier. This is the pre/post print version. The definitive version is published in Biochemical and Biophysical Research Communications, vol. 432(4), pp 683-688
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