Ruprecht-Karls-Universität Heidelberg

Open Positions in the Schiebel Lab

PhD positions, Master projects and Lab rotations

PhD position:
“Microtubules – building them at the right time, at the right place”

Microtubules are highly dynamic polymers with essential functions in chromosome segregation in mitosis and meiosis, intracellular organization, cell motility and neurogenesis. Microtubules are targets for drugs that are used in cancer therapy (Paclitaxel and Vinca alkaloids). Microtubule malfunction is associated with cancer, infertility and neurological diseases.

Using gamma-tubulin complexes, cells have developed mechanisms for the assembly of microtubules from tubulin subunits. We just have resolved the high resolution cryo-EM structure of the large vertebrate gamma-tubulin ring complex (γ-TuRC) composed of over 30 subunits (published in Nature 2019). Unexpectedly, we identified actin as a component of the γ-TuRC. The activity of the γ-TuRC is modulated in time and space by accessory factors, for example microtubule polymerases and activators such as the microcephaly protein CDK5RAP2.

In this project we aim to understand the role of actin in the γ-TuRC, when and where regulatory co-factors play a role, how they impact the structure of the γ-TuRC and how the activity of these regulators is changed in cancer and adapted in specific cell types, for example neurons.

The PhD student will be using a broad range of techniques such as cryo-electron microscopy, CRISPR/Cas9 technology for genomic knockins and knockouts and live cell imaging to study microtubule assembly.

The highly motivated PhD student should have a background in biochemistry or cell biology. Successful candidates will be part of an international team of PhD students and postdocs that works at the forefront of scientific research. The PhD student will be a member of the Heidelberg Biosciences International Graduate School (HBIGS) (http://www.hbigs.uni-heidelberg.de).

The PhD position is funded for 3 years.

Please send applications (CV, motivation letter, two references, bachelor and master transcripts) to Prof. Dr. E. Schiebel (schiebel.elmar@zmbh.uni-heidelberg.de).

Relevant publications:

Liu P, Zupa E, Neuner A, Böhler A, Loerke J, Flemming D, Ruppert T, Rudack T, Peter C, Spahn C, Gruss OJ, Pfeffer S, Schiebel E (2019). Insights into the assembly and activation of the microtubule nucleator γ-TuRC. Nature. doi: 10.1038/s41586-019-1896-6. 
Gunzelmann J, Ruthnick D, Lin TC, Zhang W, Neuner A, Jakle U, Schiebel E (2018) The microtubule polymerase Stu2 promotes oligomerization of the gamma-TuSC for cytoplasmic microtubule nucleation. Elife 7: e39932
Lin TC, Neuner A, Flemming D, Liu P, Chinen T, Jakle U, Arkowitz R, Schiebel E (2016) MOZART1 and gamma-tubulin complex receptors are both required to turn gamma-TuSC into an active microtubule nucleation template. J Cell Biol 215: 823-840
Lin TC, Neuner A, Schiebel E (2015) Targeting of gamma-tubulin complexes to microtubule organizing centers: conservation and divergence. Trends Cell Biol 25: 296-307
Lin TC, Neuner A, Schlosser YT, Scharf AN, Weber L, Schiebel E (2014) Cell-cycle dependent phosphorylation of yeast pericentrin regulates gamma-TuSC-mediated microtubule nucleation. Elife 3: e02208
Gombos L, Neuner A, Berynskyy M, Fava LL, Wade RC, Sachse C, Schiebel E (2013) GTP regulates the microtubule nucleation activity of gamma-tubulin. Nat Cell Biol 15: 1317-27
Erlemann S, Neuner A, Gombos L, Gibeaux R, Antony C, Schiebel E (2012) An extended γ-tubulin ring functions as a stable platform in microtubule nucleation. J Cell Biol 197: 59-74
Knop M, Schiebel E (1998) Receptors determine the cellular localization of a γ-tubulin complex and thereby the site of microtubule formation. EMBO J 17: 3952-3967

 

 

 

Master Projects

in the laboratory of Prof. E. Schiebel, Centre for Molecular Biology (ZMBH), University of Heidelberg, Germany

My laboratory at the ZMBH, University of Heidelberg, is offering Master projects in the following areas:

The structure and function of gamma-tubulin complexes.  Gamma-tubulin complexes assemble microtubules from tubulin subunits. Microtubules have essential functions for chromosome segregation in mitosis and meiosis, fertility, transport process in particularly in neurons. Drugs such as Taxol that target tubulin are broadly used in cancer therapy. Gamma-tubulin complexes regulate the spatial and temporal formation of microtubules. In this project we determine the structure of gamma-tubulin complexes by Cryo-EM. We will also analyse how gamma-tubulin complexes interact with microtubule polymerases.

Centrosome duplication and centriole-centrosome conversion. Centrosomes are the main microtubule organizing centres in human cells. They only duplicate once per cell cycle. Misregulation of centrosome duplication triggers a p53 response and G1 arrest. This safeguard mechanism is bypassed in cancer cells. After duplication in S phase centrosomes convert into mature centrosomes. Here we analyse the molecular mechanism of this conversion process.

Centrosome cohesion. The two centrosomes of a cell are linked together into one unit from G1 until G2 phase. At the beginning of mitosis this linkage is resolved by the kinase NEK2. Here we will study molecular mechanisms of this linkage, the structure of the linker and functional consequences if centrosome cohesion fails.

Nuclear pore complex biogenesis and spindle pole body duplication. Nuclear pore complexes and the yeast spindle pole body (SPB; yeast microtubule organizing centre) are both embedded in the double membrane of the nuclear envelope. Here we aim to understand how large protein assemblies become inserted into the nuclear envelope and how the inner and outer nuclear envelopes fuse during this embedding process.

During the 6-month master project, you will receive a Student Assistant Contract (Hiwi contract).

Please send applications with a short motivation letter, CV, bachelor transcripts and the name of one referee to Prof. Dr. E. Schiebel (schiebel.elmar@zmbh.uni-heidelberg.de).

 

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Lab Rotation

in the Laboratory of Prof. Elmar Schiebel,

ZMBH, Heidelberg University

My laboratory at the ZMBH, Heidelberg University, is offering lab rotations (6-8 weeks) for Master students who are interested in cell biology, molecular biology or biochemistry.

Topics are:

The structure and function of gamma-tubulin complexes.  Gamma-tubulin complexes assemble microtubules from tubulin subunits. Microtubules have essential functions for chromosome segregation in mitosis and meiosis, fertility, transport process in particularly in neurons. Drugs such as Taxol that target tubulin are broadly used in cancer therapy. Gamma-tubulin complexes regulate the spatial and temporal formation of microtubules. In this project we determine the structure of gamma-tubulin complexes by Cryo-EM.

Genomic tagging of genes in human cells. Presently we are establishing and optimizing approaches based on gRNA and Cas9-like enzymes to tag human genes at the 3’ and 5’ end with a toolbox of PCR cassettes (NeonGreen, GFP, mRuby, auxin degron tag). This allows tagging of human genes within 20 days.

Centrosome duplication and centriole-centrosome conversion. Centrosomes are the main microtubule organizing centres in human cells. They only duplicate once per cell cycle. Misregulation of centrosome duplication triggers a p53 response and G1 arrest. This safeguard mechanism is bypassed in cancer cells. After duplication in S phase centrosomes convert into mature centrosome. Here we analyse the molecular mechanism of the conversion process.

Nuclear pore complex biogenesis and spindle pole body duplication. Nuclear pore complexes and the yeast spindle pole body (SPB; yeast microtubule organizing centre) are both embedded in the double membrane of the nuclear envelope. Here we aim to understand how large protein assemblies become inserted into the nuclear envelope and how the inner and outer nuclear envelopes fuse during this embedding process.

Please send applications to E. Schiebel:
schiebel.elmar@zmbh.uni-heidelberg.de





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