JNK and ERK8 as downstream effectors of receptor tyrosine kinases

Iavarone, Carlo (2006) JNK and ERK8 as downstream effectors of receptor tyrosine kinases. [Tesi di dottorato] (Inedito)

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MAP kinases are a super-family of serine-threonine protein kinases expressed in all eukaryotic cells. In mammals, there are many MAP kinases with different biological functions, grouped in distinctly regulated groups, ERK1/2 (extracellular signal related kinase, ERK), JNKs (jun amino terminal kinase, JNK), p38 and “atypical” MAP kinases. The MAP kinase transduction system is particularly important in growth factors signaling, which in turn control cell growth, proliferation, differentiation, survival and migration by activating receptor tyrosine kinase (RTK) family members, as platelet-derived growth factor (PDGF) and RET. In the first report, we show that JNK is required for PDGF induction of c-myc expression. Furthermore, we identify a phylogenetically conserved AP-1 responsive element in the human, mouse and even drosophila c-myc promoter. Such element binds, in vivo, to members of the Jun family of transcription factors, c-Jun and JunD, as indicated by chromatin immunoprecipitation analysis. Finally, we show that, through this element, PDGF is able to control the activity of the c-myc transcription factor promoter in an AP-1 dependent fashion, implying the existence of a novel signaling pathway linking the PDGF receptor, through JNK and Jun proteins, to nuclear events culminating in the expression of the c-myc proto-oncogene. In the second report, we show that RET/PTC3 activates Erk8, a new member of “atypical” MAP kinases group, by an Abl-dependent but Src-independent mechanism and demonstrate a key role for Tyr981 of RET/PTC3 in the initiation of such signaling pathway. Also, by using an alternative Erk8 splice variant, Erk8, lacking the C-terminal domain, we establish a role for this region in the activation of this MAP kinase by RET/PTC3. Finally, the use of a dominant interfering molecule for Erk8 revealed that RET/PTC3 requires this MAP kinase to stimulate the c-jun transcription factor promoter.

Tipologia di documento:Tesi di dottorato
Parole chiave:Mitogen Activated Protein Kinase (MAPK), Receptor Tyrosine Kinase (RTK), Transcription factor
Settori scientifico-disciplinari MIUR:Area 06 Scienze mediche > MED/13 ENDOCRINOLOGIA
Area 06 Scienze mediche > MED/05 PATOLOGIA CLINICA
Area 05 Scienze biologiche > BIO/13 BIOLOGIA APPLICATA
Area 06 Scienze mediche > MED/09 MEDICINA INTERNA
Area 06 Scienze mediche > MED/04 PATOLOGIA GENERALE
Coordinatori della Scuola di dottorato:
Coordinatore del Corso di dottoratoe-mail (se nota)
Avvedimento, Enrico Vittorio
Tutor della Scuola di dottorato:
Tutor del Corso di dottoratoe-mail (se nota)
Formisano, Silvestro
Stato del full text:Accessibile
Numero di pagine:69
Istituzione:Università degli Studi di Napoli Federico II
Dipartimento o Struttura:Biologia e Patologia Cellulare e Molecolare “L. Califano”
Tipo di tesi:Dottorato
Stato dell'Eprint:Inedito
Denominazione del dottorato:Patologia e Fisiopatologia Molecolare
Ciclo di dottorato:XVII
Numero di sistema:784
Depositato il:01 Agosto 2008
Ultima modifica:04 Febbraio 2009 09:40

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