Die humanen Sir2-Ortholoe SIRT1 und SIRT2 als Substrate Cyclin-abhängiger Kinasen

SIRT2 is a NAD+-dependent deacetylase, one of seven human sirtuins. The main characteristic of the sirtuins is their catalytic domain of 200 to 275 amino acids, also sirtuin-homology domain. SIRT2 is a predominantly cytoplasmatic protein, which co-localises with microtubules of the cytoskeleton. In addition SIRT2 is chromatin-associated late in the G2-phase of the cell cycle and in mitosis. SIRT2 deacetylates, both in vitro and in vivo, alpha-tubulin on lysine 40 and also histone H4 on lysine 16. The deacetylation of alpha-tubulin is associated with destabilisation of the microtubule filaments and with an increase in the microtubule dynamics. These findings led to the suggestion that SIRT2 can control cell motility. It has been suggested that histone H4 lysine 16 deacetylation is related to the formation of heterochromatic areas during S-phase and in early prophase. These findings suggest that SIRT2 may have at least two important functions in cell physiology, manly in regulating cytoskeletal organisation and chromatin condensation. However very little is known about the regulation of SIRT2 function in these processes. As SIRT2 was previously found to be a substrate for cyclin dependent kinases (CDKs) in a solid phase phosphorylation screen, the aim of this work was to characterise the phosphorylation of SIRT2 by CDKs and to define the functional relevance of this modification. Moreover, the biological effect of SIRT2 should be clarified. Our results demonstrate that SIRT2 is phosphorylated exclusively on Ser-331 by p35/CDK5, Cyclin E/CDK2 and Cyclin A/CDK2 in vitro. In vivo, we confirmed that SIRT2 is phosphorylated on Ser-331 by CDK complexes. Moreover, we show that this modification regulates the enzymatic activity of SIRT2. To address the biological consequences of SIRT2 and regulation of SIRT2 through Ser-331 phosphorylation, the effect on cell adherence and neurite outgrowth were studied. SIRT2 expression resulted in a shortening of neurite length in primary murine hypocampal neurons. This effect was dependent on catalytic activity. In particular SIRT2-S331A, that cannot be inhibited by phosphorylation, showed the strongest effect. In addition SIRT2 stimulated detachment of HEK293 cells, again dependent on catalytic activity. These effects correlated with alpha-tubulin deacetylation. Together these findings provide the first information regarding post-translational regulation of SIRT2.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2006

Author dc:creator

• Pandithage, Ruwin

Contributors dc:contributor

• Lüscher, Bernhard

• info:eu-repo/classification/ddc/570
• Biowissenschaften, Biologie
• Zellmigration
• Zellskelett
• Cyclin-abhängige Kinasen
• Histone
• Deacetylierung
• Acetylierung
• Tubulin
• Mikrotubulin
• Sirtuin
• Neurone
• cell migration
• neurons
• microtuble
• acetylation
• deacetylation
• cdk

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-112524%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A49956