title: A novel regulatory role of RGS4 in STAT5B activation, neurite outgrowth and neuronal differentiation.
abstract: The Regulator of G protein Signalling 4 (RGS4) is a multitask protein that interacts with and negatively modulates opioid receptor signalling. Previously, we showed that the δ-opioid receptor (δ-OR) forms a multiprotein signalling complex consisting of Gi/Go proteins and the Signal Transducer and Activator of Transcription 5B (STAT5B) that leads to neuronal differentiation and neurite outgrowth upon δ-ΟR activation. Here, we investigated whether RGS4 could participate in signalling pathways to regulate neurotropic events. We demonstrate that RGS4 interacts directly with STAT5B independently of δ-ΟR presence both in vitro and in living cells. This interaction involves the N-terminal portion of RGS4 and the DNA-binding SH3 domain of STAT5B. Expression of RGS4 in HEK293 cells expressing δ-OR and/or erythropoietin receptor results in inhibition of [D-Ser2, Leu5, Thr6]-enkephalin (DSLET)-and erythropoietin-dependent STAT5B phosphorylation and subsequent transcriptional activation. DSLET-dependent neurite outgrowth of neuroblastoma cells is also blocked by RGS4 expression, whereas primary cortical cultures of RGS4 knockout mice (RGS4-/-) exhibit enhanced neuronal sprouting after δ-OR activation. Additional studies in adult brain extracts from RGS4-/-mice revealed increased levels of p-STAT5B. Finally, neuronal progenitor cultures from RGS4-/-mice exhibit enhanced proliferation with concomitant increases in the mRNA levels of the anti-apoptotic STAT5B target genes bcl2 and bcl-xl. These observations suggest that RGS4 is implicated in opioid dependent neuronal differentiation and neurite outgrowth via a "non-canonical" signaling pathway regulating STAT5B-directed responses.
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Paschalina
authors.initials: P
authors.lastname: Pallaki
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Eirini-Maria
authors.initials: EM
authors.lastname: Georganta
authors.affiliation: Laboratory of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Serafimidis
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Maria-Pagona
authors.initials: MP
authors.lastname: Papakonstantinou
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Papanikolaou
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Koutloglou
authors.affiliation: Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece.
authors.forename: Elsa
authors.initials: E
authors.lastname: Papadimitriou
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Adamantia
authors.initials: A
authors.lastname: Agalou
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Aggeliki
authors.initials: A
authors.lastname: Tserga
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Simeonof
authors.affiliation: Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Thomaidou
authors.affiliation: Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Gaitanou
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece. Electronic address: iro@bio.demokritos.gr.
authors.forename: Zafiroula
authors.initials: Z
authors.lastname: Georgoussi
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D002540:Cerebral Cortex / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D058953:Neural Stem Cells / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D000071446:Neuronal Outgrowth / Q000502:physiology*; D009474:Neurons / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020710:RGS Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017467:Receptors, Erythropoietin / Q000378:metabolism; D017465:Receptors, Opioid, delta / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: C494812:Bcl2l1 protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D020710:RGS Proteins; D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D017465:Receptors, Opioid, delta; D050799:STAT5 Transcription Factor; D051020:bcl-X Protein; C052617:Bcl2 protein, mouse; C098799:RGS4 protein
keywords: Deoxycholate (PubChem CID: 91896239); Differentiation; Erythropoietin; MgCl2(PubChem CID:5360315); Neurite outgrowth; Opioid receptor; PMSF (PubChem CID: 4784); RGS4; Retinoic acid (PubChem CID: 444795); STAT5B; Sodium orthovanadate (PubChem CID: 6167); Triton X-100 (PubChem CID: 5590); [(3)H]-diprenorphine (PubChem CID: 71719127); [D-Ser(2),Leu5, Thr6]-enkephalin (PubChem CID: 107847)