Volltextdatei(en) vorhanden
Titel: Regulation of the kinase MARK from Rattus norvegicus (Brekenhout, 1769) by GSK3
Sonstige Titel: Regulation der Kinase MARK aus Rattus norvegicus (Berkenhout, 1769) durch GSK3
Sprache: Englisch
Autor*in: Balusamy, Kiruthiga
Schlagwörter: Polaritätsentwicklung
GND-Schlagwörter: Posttranskriptionelle Regulation; Enzymatische Regulation; Signaltransduktion
Erscheinungsdatum: 2007
Tag der mündlichen Prüfung: 2007-01-26
Zusammenfassung: 
MARK (MAP/Microtubule Affinity Regulating Kinase), a kinase family related to PAR-1, was first discovered because of the ability to phosphorylate the neuronal microtubule-associated protein (tau/MAP2/MAP4) at the KXGS motifs located in the repeat domain. The consequence of this phosphorylation is that MAPs detach from microtubules and microtubules become highly dynamic (Drewes et al., 1997). This kind of phosphorylation of tau is enhanced in the brain of Alzheimer patients (Augustinack et al., 2002).

MARK2 isolated from mammalian brain is partly phosphorylated at both Thr208 and Ser212, which reside in the activation loop. Activation of MARK2 is achieved by phosphorylation at Thr208 by the activating kinase MARKK or LKB1 (Timm et al., 2003; Lizcano et al., 2004). It requires Ser212 to be present, but not phosphorylated, because this phosphorylation is inhibitory as judged by mutational analysis (Timm et al., 2003). In the present study, GSK3ß is identified as the inhibitory kinase that phosphorylates Ser212. This is shown by in vitro kinase assays as well as in cells.

In N2a/F113 cells, overexpression of the constitutively active MARK2T208E together with the constitutively active GSK3ßS9A, leads to the complete loss of phosphorylation at the KXGS motifs of tau indicating that MARK2 activity is inhibited.

To further characterize the influence of GSK3ß-MARK-Tau signaling cascade on the microtubule network, CHO cells are used as a cell model. Overexpression of MARK2 alone leads to phosphorylation and detachment of tau or other equivalent MAPs from the microtubules, leading to microtubule breakdown and eventually cell death. Overexpression of GSK3ß alone also leads to cell death probably due to apoptosis (Hetmann et al., 2000; Pap et al., 1998). In contrast, co-expression of GSK3ß with MARK2 inhibits the activity of MARK2 by phosphorylation of Ser212 and leads to a reduction of phosphorylation at the KXGS motifs of tau and rescue from microtubule break down and cell death. In PC12 cells, overexpression of MARK2 induces neurite outgrowth but when MARK2 is co-expressed together with GSK3ß no neurite outgrowth occurs indicating that GSK3ß is inhibiting MARK. These results reveal a novel relationship between signaling pathways regulating the neuronal cytoskeleton.
URL: https://ediss.sub.uni-hamburg.de/handle/ediss/1934
URN: urn:nbn:de:gbv:18-35048
Dokumenttyp: Dissertation
Betreuer*in: Mandelkow, Eckhard (Prof. Dr.)
Enthalten in den Sammlungen:Elektronische Dissertationen und Habilitationen

Dateien zu dieser Ressource:
Datei Beschreibung GrößeFormat  
Kiruthiga_Balusamy_2007.pdf4.21 MBAdobe PDFÖffnen/Anzeigen
Zur Langanzeige

Diese Publikation steht in elektronischer Form im Internet bereit und kann gelesen werden. Über den freien Zugang hinaus wurden durch die Urheberin / den Urheber keine weiteren Rechte eingeräumt. Nutzungshandlungen (wie zum Beispiel der Download, das Bearbeiten, das Weiterverbreiten) sind daher nur im Rahmen der gesetzlichen Erlaubnisse des Urheberrechtsgesetzes (UrhG) erlaubt. Dies gilt für die Publikation sowie für ihre einzelnen Bestandteile, soweit nichts Anderes ausgewiesen ist.

Info

Seitenansichten

28
Letzte Woche
Letzten Monat
geprüft am 18.04.2021

Download(s)

10
Letzte Woche
Letzten Monat
geprüft am 18.04.2021
Werkzeuge

Google ScholarTM

Prüfe