Loading...
Files
Date
relationships.isAuthorOf
Publisher
Philipps-Universität Marburg
item.page.supervisor-of-thesis
Abstract
Glutaredoxins (Grxs) are members of the Thioredoxin (Trx)-family of proteins that maintain reduced conditions in different cellular compartments of most species, including mammalian cells. The family of glutaredoxins can be subdivided into two groups, the monothiol Grxs (Grx3 and Grx5) with a C-G-F-S active site and the dithiol Grxs (Grx1 and Grx2) with a C-P-Y-C active site. They are located in the nucleus, cytosol, or mitochondria. Grxs are involved in numerous biological processes, for instance signal transduction. The aim of this study was to biochemically characterize the recently discovered monothiol Grx3 and to identify possible functions of Grx3 in vivo. Two homologous sequences of Grx3 were deposited in databases before. An in-silico analysis, performed in this study, identified one of these sequences as a pseudogene whereas the second sequence was identified as the coding gene. A phylogenetic analysis highlighted Grx3 as a well conserved eukaryotic protein. Localization studies identified Grx3 as an ubiquitously expressed cytosolic and nuclear protein.
During the last years some Grxs were identified as Fe/S-cluster containing proteins. Here, we have demonstrated the coordination of Fe/S-clusters in human and murine Grx3 for the first time. Indeed, in a biochemical analysis Grx3 could be characterized as a 2[2Fe-2S]-cluster containing protein in vitro and in vivo. This Fe/S-containing holo complex required the dimerization of Grx3. During the course of this study, Grx3 functions were described in the protection from cardiac hypertrophy and the activation of immune cells. This thesis revealed additional functions of Grx3 in the cell: A differential gene-expression analysis following stimulation with a phorbolester pointed to possible functions in the regulation of cytoskeletal dynamics and this was supported by our finding that HeLa-cells migrated faster in the absence of Grx3. We have detected Grx3, as the only protein of the Trx family, differentially expressed in the germinative centers of the lymphatic node and in the T-cell-zone of the spleen, confirming potential functions of Grx3 in immune cell activation. The strongest effect following Grx3 depletion, however, was seen in the distribution of iron in the cell. The silencing of Grx3 expression by siRNA resulted in strong defects in the delivery of iron to proteins and a phenotype resembling for iron-depletion, despite of normal cellular iron levels. These results might close a gap in the so far least understood process of the cellular iron metabolism - the distribution of iron from the ”free“ iron pool to proteins. One central point in these future studies will have to be the analysis whether and how these functions depend on the Fe/S-clusters complexed by the Grx3 dimer.
Review
Metadata
Contributors
Supervisor:
Dates
Created: 2010Issued: 2010-10-26Updated: 2011-08-10
Faculty
Fachbereich Biologie
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
EisenschwefelzentrumFe/S-center
DFG-subjects
GlutaredoxinHerzhypertrophieHomöostaseLokalisationZellskelett
DDC-Numbers
570
show more
Haunhorst, Petra (142557064): Eigenschaften und Funktionen des humanen monothiol Glutaredoxin 3. : Philipps-Universität Marburg 2010-10-26. DOI: https://doi.org/10.17192/z2010.0624.
License
This item has been published with the following license: In Copyright