Fachgebiet Zellbiologie

Prof. Dr. Johannes Herrmann

building 13/room 449
Tel.: +49 (0)631-205-2406
Fax: +49 (0)631-205-2492
Email: hannes.herrmann[at]biologie.uni-kl.de

Consulting hours: Wednesday 11:00 - 12:00
more information

Simone Adkins, secretary's office

Tel.: +49 (0)631-205-2490
Fax: +49 (0)631-205-2492
Email: adkins[at]biologie.uni-kl.de
Room: 13-447

Office hours: Monday - Friday from 08.00 - 11.30 am


PhD Students

Lea Bertgen- PhD Student

Tel.: +49 (0)631-205-2797
Fax: +49 (0)631-205-2492
Email: lbertgen[at]rhrk.uni-kl.de
Room: 13-430

 

Project description:

Most of the mitochondrial proteins are synthesized in the cytosol and are subsequently imported into mitochondria. However due to their a-proteobacterial origin, mitochondria retained a small part of their original genome, which in Saccharomyces cerevisiae encodes for eight proteins. Seven of these are hydrophobic membrane proteins and one is a soluble mitoribosomal protein named Var1. This protein of the small mitoribosomal subunit is conserved throughout all domains of live and homologs can either be found on the mitochondrial- or nuclear genome. While metazoans relocated the gene to the nucleus, most fungi and plants maintained the gene in mitochondria. Var1 is an aggregation prone protein that requires assistance of chaperones like the mitochondrial Hsp70 and Hsp60 to keep it in a soluble state and competent to assemble into the mitochondrial ribosome.

I want to elucidate the role of Var1 in mitochondrial ribosome assembly and characterize the specific function of the mitochondrial chaperone system in this process.

 

 


Christian Koch- PhD Student

Tel.: +49 (0)631-205-2409
Fax: +49 (0)631-205-2492
Email: c_koch[at]rhrk.uni-kl.de
Room: 13-451

 

Project description:

Most mitochondrial proteins are synthesized in the cytosol and are subsequently transported to the mitochondrial import machinery. However some precursor proteins associate with the ER surface before they reach their final destination. In recent years, it has become apparent that close cooperation and coordination of organelles in form of membrane contact sites (MCS) is vital for proper cellular function. The best studied MCS to date is ERMES a protein complex that connects the ER to mitochondria. The aim of my work is to elucidate the function of ERMES in the context of mitochondrial protein biogenesis and in particular the role it might play in the transfer of proteins from the ER to mitochondria.



Tamara Flohr - PhD Student

Tel.: +49 (0)631-205-2797
Fax: +49 (0)631-205-2492
Email: tflohr[at]rhrk.uni-kl.de
Room: 13-430

 

Project description:

Proteins of the mitochondrial matrix are typically synthesized with matrix-targeting sequences (MTS) which direct them from the cytosol into the matrix. Surprisingly, many proteins of the mitochondrial ribosome lack such sequences. One of these proteins is Mrp17, a mitoribosomal protein of the small subunit. The protein is synthesized on cytosolic ribosomes, imported into the mitochondrial matrix and finally assembles into the Mitoribosome. Although Mrp17 has no presequence, the protein is imported very efficiently. The focus of my study is to investigate the motives that direct the protein into the matrix and identify the components that mediate the import reaction.

 

 

Saskia Rödl - PhD Student

Tel.: +49 (0)631-205-2880
Fax: +49 (0)631-205-2492
Email: roedl[at]rhrk.uni-kl.de
Room: 13-455

 

Project description:

Yeast can produce energy either by respiration or fermentation, depending on the carbon source availability. Changing the carbon source causes a variety of changes in the cells, including protein expression and degradation. So far, there is much known about cellular adaptations to respiratory growth conditions but not vice versa. In this context my study will focus on cellular modulations caused by changing growth conditions from respiration to fermentation. I’m particularly interested in glucose-induced protein degradation and its connection to the regulation of mitochondrial biogenesis.


Lena Krämer - PhD Student

Tel. +49 (0)631-205-2797
Fax: +49 (0)631-205-2492
Email: l_kraeme[at]rhrk.uni-kl.de
Room: 13-430

 

Project description:

A functional mitochondrial protein import is essential for cellular fitness and survival. A loss of protein translocation is associated with oxidative stress, neurodegenerative diseases as well as metabolic disorders. As in other stress situations, the cell performs a strongly regulated stress reaction after mitochondrial import block. In this mitoprotein-induced stress response, the proteasome plays a crucial role, as it degrades mitochondrial precursor proteins which accumulate in the cytosol.

In my studies I concentrate on the molecular mechanisms by which the proteasome plays a role during mitochondrial biogenesis.

Carina Groh- PhD Student

Tel. +49 (0)631-205-2797
Fax: +49 (0)631-205-2492
Email: cgroh[at]rhrk.uni-kl.de
Room: 13-430

 

Project description:

The function of the cell depends on properly folded proteins. To maintain the functional activity of the proteins, a complex network of molecular chaperones, the ubiquitin-proteasome system and many cofactors are required. If this orchestra fails and protein folding is impaired, the cell has to deal with many issues. Neurodegenerative diseases or aging are extreme examples of what might happen when protein folding becomes problematic. Recent studies revealed that also mitochondrial problems lead to cytosolic proteotoxic stress.

Until today it remains unclear what the precise effect of different proteotoxic stresses on cellular functionality is. In this context I will study the impact of mitochondrial stress on the cytosolic proteostasis.

Katharina Knöringer - PhD Student

Tel.: +49 (0)631-205-2409
Fax: +49 (0)631-205-2492
Email: knoering[at]rhrk.uni-kl.de
Room: 13-451

 

Project description:

Mitochondria have an elaborate machinery to import proteins that are synthesized on cytosolic ribosomes. Many different pathways and mechanisms of protein translocation across the mitochondrial membranes are studied in great detail. In contrast, very little is known about how the proteins reach the mitochondrial import channels in the first place.

For a long time, it was believed that all mitochondrial proteins are first completely synthesized in the cytosol and then subsequently targeted to mitochondria in a post-translational manner. In the last years, this dogma has been challenged by compelling evidence for the existence of co-translational import. At least some proteins appear to be translated in direct vicinity to the translocation channel and their import likely starts before translation is completed. However, the extent and physiological relevance of co-translational import remain elusive.

I am interested in how the cell decides between co- and posttranslational import. Another focus of my studies will be environmental conditions which have an impact on the balance between the two import modes.

Büsra Güngör - PhD

Tel.: +49 (0)631-205-2880
Email: bguengue[at]rhrk.uni-kl.de
Room: 13-455

 

Project description:


Bachelor/Master Students

Uli Stock - Master Student

Tel.: +49 (0)631-205-22797
Fax: +49 (0)631-205-2492
Email: ustock[at]rhrk.uni-kl.de
Room: 13-430


Technische Mitarbeiter

Sabine Knaus

Tel. +49 (0)631-205-2880
Fax +49 (0)631-205-2492
Email: s.knaus[at]biologie.uni-kl.de
Room: 13-455


Andrea Trinkaus

Tel. +49 (0)631-205-2111
Fax +49 (0)631-205-2492
Email: trinkaus[at]biologie.uni-kl.de
Room: 13-432

Vera Nehr

Tel. +49 (0)631-205-2797
Fax +49 (0)631-205-2492
Email: vfritzin[at]rhrk.uni-kl.de
Room: 13-430

Cornelia Parent

Tel. +49 (0)631-205-2490
Fax +49 (0)631-205-2492
Email: parent[at]rhrk.uni-kl.de
Room: 13-423

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