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Macromolecular Assemblies in Metabolic Regulation and Polyketide Biosynthesis

English title Macromolecular Assemblies in Metabolic Regulation and Polyketide Biosynthesis
Applicant Maier Timm
Number 179323
Funding scheme Project funding (Div. I-III)
Research institution Biozentrum der Universität Basel
Institution of higher education University of Basel - BS
Main discipline Molecular Biology
Start/End 01.04.2018 - 31.03.2023
Approved amount 1'008'000.00
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All Disciplines (2)

Molecular Biology

Keywords (14)

biosystems engineering; crystallography; structural biology; multienzyme; fatty acid biosynthesis; electron microscopy; molecular machines; metabolism; target of rapamycin; mTOR; acetyl-CoA carboxylase; ACC; cryoEM; enzyme

Lay Summary (German)

Das Zellwachstum im menschlichen Körper wird durch aufwändige Regelsystem gesteuert. Das Protein mTOR dient dabei als übergeordnete Steuerzentrale, die viele Stoffwechselwege kontrolliert. Besonders zentrale Enzyme im Stoffwechsel besitzen daneben eigene Kontrollmechanismen. In diesem Projekt untersuchen wir die Strukturen und Regelmechanismus zentraler Proteinkomplex im menschlichen Stoffwechsel.
Lay summary

Das Protein mTOR überträgt Phosphatgruppen auf Zielproteine und regelt dadurch deren Aktivität und letztlich das Zellwachstum. mTOR wird durch die Verfügbarkeit von Nährstoffen und Energie sowie extrazelluläre Signale von Hormonen und Wachstumsfaktoren kontrolliert. Der Aufbau von Fetten ist ein zentraler durch mTOR kontrollierter Stoffwechselweg, dessen Fehlregulation in vielen Krankheiten beobachtet wird. Neben mTOR spielt dabei das Enzym Acetyl-CoA Carboxylase (ACC) eine wichtige Rolle. Es führt den ersten spezifischen Schritt der Fettherstellung aus und wird durch Produkthemmung und Substrataktivierung kontrolliert. Bekannte Hemmstoffe von mTOR und ACC sind Naturstoffe aus der Klasse der Polyketide. Diese werden in riesigen Fertigungsstrassen, den Polyketidsynthasen (PKS), von Mikroorganismen aufgebaut.

In diesem Projekt untersuchen wir mit den Mitteln der Strukturbiologie die wenig bekannten strukturellen Grundlagen und Mechanismen der Regulation von mTOR Komplexen und ACC und schaffen eine Basis für den gezielten Auf- und Umbau von PKS.

Ziel des Projektes ist es, Grundlagenwissen zur Regulation des Stoffwechsels und zur Funktion biosynthetischer Proteine zu gewinnen. Die Erkenntnisse dieses Projektes tragen langfristig zum Verständnis von Abweichungen des Stoffwechsels zum Beispiel in Tumoren und zur Entwicklung entsprechender Wirkstoffe bei.   

Direct link to Lay Summary Last update: 14.04.2018

Responsible applicant and co-applicants



The 3.2-Å resolution structure of human mTORC2
Scaiola Alain, Mangia Francesca, Imseng Stefan, Boehringer Daniel, Berneiser Karolin, Shimobayashi Mitsugu, Stuttfeld Edward, Hall Michael N, Ban Nenad, Maier Timm (2020), The 3.2-Å resolution structure of human mTORC2, in Science advances, 6(45), eabc1251.
The architectures of iterative type I PKS and FAS.
Herbst Dominik A, Townsend Craig A, Maier Timm (2018), The architectures of iterative type I PKS and FAS., in Natural product reports, 35(10), 1046-1069.


cryo-EM structure of human mTOR complex 2, overall refinement

Author Scaiola, Alain; Mangia, Francesca; Imseng, Stefan; Boehringer , Daniel; Ban, Nenad; Maier, Timm
Publication date 18.11.2020
Persistent Identifier (PID) 6ZWM
Repository Protein Data Bank
cryo-EM structure of human mTOR complex 2, overall refinement


Group / person Country
Types of collaboration
Sebastian Hiller, Uni Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Jörn Piel, ETH Zürich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Craig Townsend, Johns Hopkins University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Marek Basler, Uni Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
ASCB-EMBO meeting 2018- SIG Cellular Organization of Metabolism: Biology, Structure, and Function of Enzyme Polymers Talk given at a conference Controlling the activity of eukaryotic acetyl-CoA carboxylases: conformational locking and polymerization 08.12.2020 San Diego, United States of America Maier Timm;
Directing Biosynthesis Talk given at a conference The architecture of polyketide synthases 29.06.2020 Edinburgh, Keynote postponed to 2022 /Covid-19, Great Britain and Northern Ireland Maier Timm;
Vienna CryoEM symposium Talk given at a conference The structural basis for regulating acetyl-CoA carboxylase 14.02.2020 Vienna, Austria Maier Timm;
Drug Discovery 2019 Talk given at a conference Novel opportunities for targeting metabolic regulation from imaging macromolecular assemblies 06.11.2019 Liverpool, Great Britain and Northern Ireland Maier Timm;
Imperial College Section of Structural Biology Seminar Individual talk The structural basis for regulation of acetyl CoA carboxylase 08.11.2018 London, Great Britain and Northern Ireland Maier Timm;

Communication with the public

Communication Title Media Place Year
Other activities Supervision of Matura thesis, V. Baumann Western Switzerland 2018

Associated projects

Number Title Start Funding scheme
159696 Multienzymes in Lipid and Polyketide Biosynthesis 01.04.2015 Project funding (Div. I-III)
138262 Multienzymes and the Regulation of Eukaryotic Lipid Metabolism 01.01.2012 Project funding (Div. I-III)


The regulation of cellular proliferation requires the integration of a large number of input signals, such as nutrient availability and growth factor signaling for the short- and long-term regulation of anabolic and catabolic reactions. The mTOR kinase acts as a central regulator of cell growth and controls transcription, translation, lipid and nucleotide metabolism. mTOR exerts its function in two large protein complexes, which in turn are regulated by direct interactions with proteins that link mTOR activitation to sensing processes. Critical steps in metabolism require additional options for short-term regulation, a prominent example is the committed step in fatty acid biosynthesis. This step is carried out by the large acetyl-CoA carboxylase (ACC) multienzyme, which integrates several functional domains into one polypeptide and offers extended options for regulation. Human ACC is controlled via phosphorylation, allosteric feedback activation and inhibition, as well as by polymerization into giant filaments. Despite the outstanding relevance of mTOR and ACC in metabolic disorders, diabetes and cancer, the mechanistic and structural basis for their regulation remains poorly understood. The microbial polyketide synthases (PKS) are large assembly line proteins for the production of highly potent secondary metabolites. Their polyketide products are amongst the most successful compound classes in drug discovery and include common antibiotics, as well as the immunosuppressant mTOR inhibitor rapamycin and the ACC inhibitor soraphen A. The structure of PKS products is directly encoded in the structure of PKSs, which are organized into modules of varying domain composition. Evolutionary variation of domain content and modular arrangement has led to the outstanding diversity of microbial polyketides. Re-engineering PKS for production of novel polyketides is currently hindered by a lack of knowledge on domain specificities, as well as on the complex interplay between domains and entire modules required for substrate shuttling. Here, we propose to study the regulation of human mTOR (subproject A) and ACC (subproject B) by formation of macromolecular assemblies, as well as substrate loading and higher order structures of PKS (subproject C). We aim to obtain detailed mechanistic insights by combining high-resolution structure determination, in particular via cryo electron microscopy, with functional analysis, mechanistic trapping, and analysis of dynamics in the cellular context. The expected results are of central relevance for PKS engineering for the production of novel drug candidates as well as for the development of strategies for metabolism-based therapeutic intervention in metabolic diseases and cancer.