Molecular Cell Biology
About
Head: Dr. Anja Bremm
Our group is located at the Buchmann Institute for Molecular Life Sciences (Campus Riedberg), in close vicinity to the natural sciences faculties of the Goethe University and the Max Planck Institutes for Biophysics and Brain Research.
Members
Group Members
Dr. Anja Bremm
Anja studied Biology at the Georg-August University Göttingen and obtained her PhD from Technical University Munich (TUM). Her dissertation focused on the crosstalk between the cell adhesion molecule E-cadherin and EGF receptor signalling in gastric cancer. For her post-doctoral studies, Anja moved to Cambridge (UK) where she worked on atypical K11-linked ubiquitin chains in David Komander's group at the MRC Laboratory of Molecular Biology (LMB). After four years in UK, Anja returned to Germany and joined Ivan Dikic's group at Goethe University Frankfurt. Since 2014, she is an independent group leader and head of an Emmy Noether research group funded by the German Research Foundation (DFG).
Mila Basic
Mila comes from Croatia. She obtained her bachelor’s degree in Molecular biology at the University of Zagreb. After spending a year abroad during her ERASMUS exchange program at the TU Dresden, she decided to continue her education there and obtain her master’s degree from biotec, studying Molecular bioengineering. For her master thesis she joined the lab of Francis Stewart, where she was introduced to gene expressing systems in stem cells. In particular, she was interested in auxin-inducible degron system for expressing epigenetic regulators and investigation of their influence on the gene expression. Afterwards, Mila joined the new lab of Anja Bremm, where her interest shifted towards protein biochemistry. She is now investigating the roles of deubiquitinating enzymes in autophagy regulation. When not in lab, she can be found passionately doing various sports or enjoying a nice cup of coffee in a relaxing atmosphere.
Verena Bittl
Verena obtained her Bachelor´s degree in Biology at the Philipps University Marburg, where she studied protein trafficking events in the malaria parasite Plasmodium falciparum during the course of her Bachelor's thesis. Subsequently, she moved to Heidelberg to study Molecular and Cellular Biology at the Ruprecht Karls University. For her Master's thesis, Verena joined the lab of Sebastian Schuck to find potential ER-phagy substrates as a tool to study selective autophagy of the ER in yeast. In May 2016, Verena joined the Bremm lab and shifted her focus on selective autophagy in human cells.
Alexandra Kalb
Alexandra obtained her Bachelor’s degree in Chemistry at the Technische Hochschule Nürnberg and moved to Frankfurt to focus her Master’s studies on Biochemistry at the Goethe University. For her Master’s thesis, she joined the group of Anja Bremm, where she investigated the role of deubiquitinating enzymes in retromer-mediated protein trafficking and autophagy. Alexandra started her PhD in the lab in January 2016 and continues with her project working on DUBs in protein trafficking and sorting.
Anja Kück
Anja, also known as little Anja, to avoid confusion with the boss, studies Biochemistry at the Goethe University Frankfurt. After an internship in the Bremm lab in the fall/winter 2015 she is now back for her Master's thesis working alongside Mila Bašić to characterize the role of deubiquitinating enzymes in autophagy.
Julia Mader
Julia did her Bachelor´s degree in Biology at the Julius Maximilians University of Würzburg. She obtained her Master´s degree in Biological Science at the University of Konstanz. For her Master´s thesis, Julia joined the group of Martin Scheffner and studied mechanisms involved in regulation of p53 ubiquitination and neddylation. In April 2014, she started her PhD in the Molecular Cell Biology group and is currently investigating the functional role of atypical protein ubiquitination in hypoxia signaling and mechanisms in regulating DUB activity.
Projects
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Project I - Control of deubiquitinating enzymes (DUBs)
Control of deubiquitinating enzymes (DUBs)
Ubiquitination plays an essential role in modulating protein functions and deregulation of the ubiquitin system leads to the development of multiple human diseases. Ubiquitin (Ub) is covalently attached via its C-terminus to substrate lysine residues by a well-orchestrated enzymatic cascade including an E1 Ub-activating enzyme, an E2 Ub-conjugating enzyme and E3 ligases. Ubiquitin itself contains seven lysine residues and an N-terminal amino group, all of which can be linked to another ubiquitin to form polymers of eight different linkage types. It was shown that differently linked ubiquitin chains trigger distinct cellular responses, suggesting that ubiquitin can act as a code to store and transmit information.
Given the large complexity of possible ubiquitin modifications, the appropriate removal of ubiquitin by DUBs presents a significant problem to the cell. DUBs are essential to maintain free ubiquitin levels, rescue proteins from ubiquitin-mediated degradation, and control the dynamics of ubiquitin-mediated signaling events. Thus, the activity of DUBs must be tightly regulated in order to recognize both the correct substrate and the correct context in which to deubiquitinate target proteins. In addition to their physiological function, we are investigating cellular mechanisms of how the catalytic activity of these proteases is controlled (e.g. by PTMs, protein binding partners, or reactive oxygen species (ROS), especially in cellular stress responses to hypoxia.
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Project II - Regulation of autophagy by deubiquitinating enzymes (DUBs)
Regulation of autophagy by deubiquitinating enzymes (DUBs)
Autophagy selectively delivers cytoplasmic components to lysosomes for degradation and recycling. Increasing evidence suggests that protein ubiquitination is directly involved in the regulation of autophagy by (a) controlling stability of upstream regulators or components of the autophagy machinery, and (b) facilitating the recruitment of autophagy adaptors. While a variety of ubiquitin E3 ligases were already demonstrated to govern autophagic substrate degradation, the role of DUBs in this context remains largely elusive. DUBs are essential for cells to rescue proteins from ubiquitin-mediated degradation, and to tightly control the dynamics of ubiquitin-mediated signaling events. Many DUBs associate with E3 ligase complexes to fine-tune the ubiquitination status of a common substrate.
Our project aims to characterize DUBs that are indispensable for the correct course of autophagy. A mass spectrometry-based interactome analysis revealed interactions between several DUBs and regulators or constituents of the autophagy machinery. We are characterizing the impact of these enzymes on autophagy induction, autophagosome biogenesis, and subsequent substrate clearance. These studies will allow a better understanding of how ubiquitination modulates the autophagy pathway by the combined action of E3 ligases and DUBs.
Contact
Head: Dr. Anja Bremm
Buchmann Institute for Molecular Life Sciences (BMLS)
Goethe University Frankfurt
Max-von-Laue-Str. 15
60438 Frankfurt am Main
Germany
Tel (office): +49 (0) 69 798 42510
Tel (lab): +49 (0) 69 798 42509
Fax: +49 (0) 69 798 763 42510