Florian Stengel - University of Konstanz & Jan Erzberger - University of Texas Southwestern)

from 10:30 to 11:15:

Prof. Florian Stengel (University of Konstanz, mass spectrometry, stuctural and systems biology)

"Studying proteome organization and cellular compartmentalization: from proteins to functional compartments"

Abstract: Cells need to control an almost infinite number of processes and biochemical reactions in time and space. A key concept is the organization of the cellular space into functional units and compartments. Cellular compartmentalization scales from single molecules over protein complexes of varying complexity to large membrane surrounded organelles. On the protein and protein complex level posttranslational modifications lead to the generation of functional proteoforms which confer both complexity and dynamics of the system.The emerging concept of liquid-liquid phase separation is increasingly identified as a mechanism to organize the cellular space into functional units via the formation of biomolecular condensates. Biomolecular condensates offer a confined space where specific protein protein interactions (PPIs) can take place in order to facilitate distinct biochemical reactions. As the formation and maturation of biomolecular condensates appears to be of fundamental relevance to biology and a disease-associated process, it is critical to understand the underlying molecular interactions. During my talk I will describe how mass spectrometry-based proteomics can be used to study PPIs and protein dynamics within molecular condensates, focusing on stress granules and in particularly the role of chaperones in organizing and maintaining these specific molecular condensates.

Bio: Florian Stengel studied biochemistry at the FU Berlin and Harvard University. After completing his diploma thesis as a DAAD foreign exchange scholar with Pamela Silver in functional genomics at Harvard Medical School, he went to the University of Cambridge to earn his PhD with Carol Robinson. In 2011 he joined the laboratory of Ruedi Aebersold at ETH Zurich as an Sir Henry Wellcome Fellow. Since 2015 he heads his own laboratory at the University of Konstanz, first as an Assistant Professor and Emmy-Noether Group Leader and since 2022 as Full Professor and Heisenberg Professor of Biochemistry. He is the recipient of the 2020 Manfred-Fuchs Prize of the Heidelberg Academy of Sciences and Humanities.

from 11:15 to 12:00:

Prof. Jan Erzberger (UT southwestern Texas, CryoEM of Ribosome biogenesis)

"Exploring rRNA Remodeling Mechanisms: The Role of DEAD-box ATPases in Ribosome Assembly"

Abstract: ATPases of the DEAD-box family are ubiquitous, highly conserved enzymes that play essential roles in ribosome assembly. ATPase activity is proposed to drive the remodeling of secondary and tertiary RNA structures, facilitating the ordered addition of proteins to form functional ribonucleoprotein (RNP) modules. Because of the transient nature of their interactions, we have little understanding of how DEAD-box proteins engage and remodel their rRNP assembly substrates. We used genetic manipulation of yeast strains to trap and enrich transient complexes of DEAD-box ATPases bound to large ribosomal (60S) assembly intermediates. Cryo-EM reconstructions of three distinct pre-60S states, at resolutions ranging from 2.3 to 2.8 Å, reveal a critical function for DEAD-box proteins in the proper assembly of core RNA elements during 60S maturation.

Bio: Dr. Erzberger received his undergraduate degree in Biological Chemistry from Harvard University and his Ph.D. Molecular and Cell Biology in the lab of James Berger at the University of California, Berkeley, studying DNA replication initiation in bacteria. During his postdoctoral training in the laboratory of Nenad Ban at the ETH Zürich, Dr. Erzberger focused on studies of the eukaryotic translation initiation machinery, developing a novel hybrid structural approach, combining x-ray crystallography, cryo-electron microscopy and mass-spectrometry to investigate the role of eIF3, a large, multiprotein initiation factor. Since joining the faculty of UT Southwestern in 2015, Dr. Erzberger has using integrative methodologies centered on cryo-electron microscopy to elucidate the assembly mechanism of the large (60S) ribosomal subunit, in particular the role of ATPases, GTPases and methyltransferases in carrying out RNA modification reactions to guide the accurate biogenesis of 60S subunits.

Contact : Riccardo Pellarin