1. Differential Phosphorylation of c-Jun and JunD in Response to the Epidermal Growth Factor Is Determined by the Structure of MAPK Targeting Sequences
- Author
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Annalisa Morano, Giovanna Fasanella, Anna M. Musti, Marcello Maggiolini, Adriana Gallo, Maria Vinciguerra, Adele Vivacqua, and Concetta Cuozzo
- Subjects
MAPK/ERK pathway ,Molecular Sequence Data ,Biochemistry ,Cell Line ,Mice ,Structure-Activity Relationship ,Protein structure ,Epidermal growth factor ,Animals ,Humans ,Amino Acid Sequence ,Phosphorylation ,Molecular Biology ,Peptide sequence ,Binding Sites ,Epidermal Growth Factor ,integumentary system ,Chemistry ,c-jun ,JNK Mitogen-Activated Protein Kinases ,Cell Biology ,Molecular biology ,Protein Structure, Tertiary ,Cell culture ,Mitogen-Activated Protein Kinases ,Signal transduction ,Sequence Analysis ,Signal Transduction - Abstract
MAPK phosphorylation of various substrates is mediated by the presence of docking sites, including the D domain and the DEF motif. Depending on the number and sequences of these domains, substrates are phosphorylated by specific subsets of MAPKs. For example, a D domain targets JNK to c-Jun, whereas a DEF motif is required for ERK phosphorylation of c-Fos. JunD, in contrast, contains both D and DEF domains. Here we show that these motifs mediate JunD phosphorylation in response to either ERK or JNK activation. An intact D domain is required for phosphorylation and activation of JunD by both subtypes of MAPK. The DEF motif acts together with the D domain to elicit efficient phosphorylation of JunD in response to the epidermal growth factor (EGF) but has no function on JunD phosphorylation and activation by JNK signaling. Furthermore, we show that conversion of a c-Jun sequence to a canonical DEF domain, as it is present in JunD, elicits c-Jun activation in response to EGF. Our results suggest that evolution of a particular modular system of MAPK targeting sequences has determined a differential response of JunD and c-Jun to ERK activation.
- Published
- 2004