Jan-Hannes Schäfer

Structure of the ceramide-bound SPOTS complex

Jan-Hannes Schäfer, Carolin Körner, Bianca M. Esch, Sergej Limar, KristianParey, Stefan Walter, Dovile Januliene#, Arne Moeller#, Florian Fröhlich# Sphingolipids are structural membrane components that also function in cellular stress responses. The serine palmitoyl-transferase (SPT) catalyzes the rate limiting step in sphingolipid biogenesis. Its activity is tightly regulated through multiple binding partners, including Tsc3, Orm proteins, […]

Structure of the ceramide-bound SPOTS complex Read More »

Conformational variability of cyanobacterial ChlI, the AAA+ motor of magnesium chelatase involved in chlorophyll biosynthesis

Dmitry Shvarev, Alischa Ira Scholz, Arne Moeller Magnesium chelatase is a conserved enzyme complex responsible for the first committed step of chlorophyll biosynthesis in photosynthetic organisms, which is the addition of magnesium to the chlorophyll precursor, protoporphyrin IX. The complex is composed of the catalytic subunit ChlH, the bridging subunit ChlD, and the subunit ChlI,

Conformational variability of cyanobacterial ChlI, the AAA+ motor of magnesium chelatase involved in chlorophyll biosynthesis Read More »

Yck3 casein kinase-mediated phosphorylation determines Ivy1 localization and function at endosomes and vacuole

Sophie Grziwa, Jan-Hannes Schäfer, Raffaele Nicastro, Annabel Arens, Claudio De Virgilio, Florian Fröhlich, Arne Moeller, Jieqiong Gao, Lars Langemeyer, Christian Ungermann The casein kinase Yck3 is a central regulator at the vacuole that phosphorylates several proteins involved in membrane trafficking. Here, we set out to identify novel substrates. We localized endogenously tagged Yck3 not only

Yck3 casein kinase-mediated phosphorylation determines Ivy1 localization and function at endosomes and vacuole Read More »

Structure of the metazoan Rab7 GEF complex Mon1–Ccz1–Bulli

Eric Herrmann, Jan-Hannes Schäfer, Stephan Wilmes, Christian Ungermann, Arne Moeller, and Daniel Kümmel The endosomal system of eukaryotic cells represents a central sorting and recycling compartment linked to metabolic signaling and the regulation of cell growth. Tightly controlled activation of Rab GTPases is required to establish the different domains of endosomes and lysosomes. In metazoans,

Structure of the metazoan Rab7 GEF complex Mon1–Ccz1–Bulli Read More »

Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation

Ann-Christin Borchers, Maren Janz, Jan-Hannes Schäfer, Arne Moeller, Daniel Kümmel, Achim Paululat, Christian Ungermann, Lars Langemeyer Maturation from early to late endosomes depends on the exchange of their marker proteins Rab5 to Rab7. This requires Rab7 activation by its specific guanine nucleotide exchange factor (GEF) Mon1- Ccz1. Efficient GEF activity of this complex on membranes

Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation Read More »

Cotranslational assembly of membrane protein/nanoparticles in cell-free systems

Roman Levin, Zoe Köck, Janosch Martin, René Zangl, Theresa Gewering, Leah Schüler, Arne Moeller, Volker Dötsch, Nina Morgner, Frank Bernhard Nanoparticles composed of amphiphilic scaffold proteins and small lipid bilayers are valuable tools for reconstitution and subsequent functional and structural characterization of membrane proteins. In combination with cell-free protein production systems, nanoparticles can be used

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The ABC transporter MsbA adopts the wide inward-open conformation in E. coli cells

Laura Galazzo, Gianmarco Meier, Dovile Januliene, Kristian Parey, Dario De Vecchis, Bianca Striednig, Hubert Hilbi, Lars V. Schäfer, Ilya Kuprov, Arne Moeller, Enrica Bordignon, Markus A. Seeger Membrane proteins are currently investigated after detergent extraction from native cellular membranes and reconstitution into artificial liposomes or nanodiscs, thereby removing them from their physiological environment. However, to

The ABC transporter MsbA adopts the wide inward-open conformation in E. coli cells Read More »

Structure of the HOPS tethering complex, a lysosomal membrane fusion machinery

Dmitry Shvarev, Jannis Schoppe, Caroline König, Angela Perz, Nadia Füllbrunn, Stephan Kiontke, Lars Langemeyer, Dovile Januliene, Kilian Schnelle, Daniel Kümmel, Florian Fröhlich, Arne Moeller, Christian Ungermann Lysosomes are essential for cellular recycling, nutrient signaling, autophagy, and pathogenic bacteria and viruses invasion. Lysosomal fusion is fundamental to cell survival and requires HOPS, a conserved heterohexameric tethering

Structure of the HOPS tethering complex, a lysosomal membrane fusion machinery Read More »

Mechanism of multimodal substrate translocation in P-glycoprotein

Theresa Gewering, Deepali Waghray, Kristian Parey, Joel Zapata, Pengyi Zhao, Hao Chen, Dovile Januliene, Ina L. Urbatsch, Arne Moeller, Qinghai Zhang P-glycoprotein (Pgp) is a highly dynamic ATP-binding cassette transporter that confers cancer multidrug resistance and mediates the bioavailability and pharmacokinetics of many drugs. Structural and biochemical data have provided insights into the binding of

Mechanism of multimodal substrate translocation in P-glycoprotein Read More »

Frozen motion: how cryo-EM changes the way we look at ABC transporters

Dmitry Shvarev, Dovile Januliene, Arne Moeller ATP-binding cassette (ABC) transporters are widely present molecular machines that transfer substrates across the cell membrane. ABC transporters are involved in numerous physiological processes and are often clinical targets. Structural biology is fundamental to obtain the molecular details underlying ABC transporter function and suggest approaches to modulate it. Until

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