Charakterisierung von Cyclin L2 : ein neuer Vertreter der Cyclin-Familie

The dual-specifity tyrosin (Y) phosphorylation-regulated kinase-1A (DYRK1A) plays a prominent role in development of the central nervous system. The gene is located within the down-syndrome-critical-region on chromosome 21. The molecular mediation of the protein function of DYRK1A remains unclear. Cyclin L2, a recently identified substrates of DYRK1A, combines the unique combination of cyclin domain and arginine-serine-rich domain (rs-domain). These rs-domains comprise a hallmark for splicing factors. The intention of this thesis was to characterize cyclin L2 and to analyze the interaction between DYRK1A and cyclin L2. Application of a cyclin L2-specific antibody revealed in vivo expression in isolated nuclei of mouse-testes. Subcellular localization of cyclin L2 was assessed via live-cell-imaging. Cyclin L2, and the closely related cyclin L1, are organized in nuclear speckles, known to be the place of supply, modification and storage of splicing factors. The fact that DYRK1A is allocated in nuclear speckles as well indicates a physiological interaction between both proteins. Furthermore this thesis demonstrates that overexpressed DYRK1A but not the catalytic inactive form of DYRK1A generates an additional band of cyclin L2 with less electrophoretic mobility in western blot assays, which is typical for phosphorylation of proteins and refers to a phosphorylation of cyclin L2 by DYRK1A. Western blot assays also prove the interaction of cyclin L2 and the endogenous cyclin dependent kinase PITSLRE p110 (cdk11) in vivo. Compared to cyclin L1 and PITSLREp110 this interaction is weaker and so far no other catalytic active partner of cyclin L2 is known. In contrast to this analogy of both L-type-cyclins photobleaching-technique visualized that cyclin L1 and cyclin L2 act entirely opposed: cyclin L2 proved to be highly mobile within the nucleus whereas cyclin L1 seemed to be totally immobile, a unique and characteristic trait for proteins with an rs-domain. By using chimeric proteins the rs-domain was held to be responsible for this opposed mobility behavior, which was as yet an undescribed function of rs-domains. This thesis characterizes cyclin L2 as a new member of the cyclin family with specific properties different from cyclin L1. The results assume an interaction between cyclin L2 and DYRK1A in vivo and therefore DYRK1A might play a role concerning posttranscriptional modification by splicing.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2008

Author dc:creator

• Spelten, Oliver

Contributors dc:contributor

• Becker, Walter

• info:eu-repo/classification/ddc/610
• Kinasen
• Cyclin-abhängige Kinasen
• Enzymsubstrat
• Cycline
• Spleißfaktor
• Down-Syndrom
• Medizin
• DYRK1A
• Cyclin L2
• Spleißen
• FLIP
• FRAP
• splicing

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-112631%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50069