The c-Jun N-terminal kinase (JNK) is a mitogen-activated protein kinase (MAPK) activated by stress-signals and involved in many different diseases. Previous results proved the powerful effect of the cell permeable peptide inhibitor d-JNKI1 (d-retro-inverso form of c-Jun N-terminal kinase-inhibitor) against neuronal death in CNS diseases, but the precise features of this neuroprotection remain unclear. We here performed cell-free and in vitro experiments for a deeper characterization of d-JNKI1 features in physiological conditions. This peptide works by preventing JNK interaction with its c-Jun N-terminal kinase-binding domain (JBD) dependent targets. We here focused on the two JNK upstream MAPKKs, mitogen-activated protein kinase kinase 4 (MKK4) and mitogen-activated protein kinase kinase 7 (MKK7), because they contain a JBD homology domain. We proved that d-JNKI1 prevents MKK4 and MKK7 activity in cell-free and in vitro experiments: these MAPKK could be considered not only activators but also substrates of JNK. This means that d-JNKI1 can interrupt downstream but also upstream events along the JNK cascade, highlighting a new remarkable feature of this peptide. We also showed the lack of any direct effect of the peptide on p38, MEK1, and extracellular signal-regulated kinase (ERK) in cell free, while in rat primary cortical neurons JNK inhibition activates the MEK1-ERK-Ets1/c-Fos cascade. JNK inhibition induces a compensatory effect and leads to ERK activation via MEK1, resulting in an activation of the survival pathway-(MEK1/ERK) as a consequence of the death pathway-(JNK) inhibition. This study should hold as an important step to clarify the strong neuroprotective effect of d-JNKI1.
|Titolo:||c-Jun N-terminal kinase binding domain-dependent phosphorylation of mitogen-activated protein kinase kinase 4 and mitogen-activated protein kinase kinase 7 and balancing cross-talk between c-Jun N-terminal kinase and extracellular signal-regulated kinase pathways in cortical neurons|
|Parole Chiave:||d-JNKI1; ERK; JNK; MEK1; MKK4; MKK7; activating transcription factor 2; amino acid sequence; analysis of variance; animals; animals, newborn; Cerebral Cortex; Dose-Response Relationship, Drug; Enzyme Activation; Extracellular Signal-Regulated MAP kinases; JNK mitogen-activated protein kinases; l-lactate dehydrogenase; MAP kinase kinase 4; MAP kinase kinase 7; neurons; peptides; phosphorylation; protein binding; protein interaction domains and motifs; rats; signal transduction; ets-domain protein elk-1; neuroscience (all)|
|Settore Scientifico Disciplinare:||Settore BIO/16 - Anatomia Umana|
Settore BIO/14 - Farmacologia
|Data di pubblicazione:||2009|
|Digital Object Identifier (DOI):||10.1016/j.neuroscience.2008.11.049|
|Appare nelle tipologie:||01 - Articolo su periodico|