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bioRxiv · 10.1101/2022.01.12.475930

Cross-linking of the Endolysosomal System Reveals Flotillin Structures and Putative Cargo

Singh, J.·Elhabashy, H.·Muthukottiappan, P.·Stepath, M.·Eisenacher, M.·Kohlbacher, O.·Gieselmann, V.·Winter, D.
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Abstract

Lysosomes are well-established as the main cellular organelles for the degradation of macromolecules and emerging as regulatory centers of metabolism. They are of crucial importance for cellular homeostasis, which is exemplified by a plethora of disorders related to alterations in lysosomal function. In this context, protein complexes play a decisive role, regulating not only metabolic lysosomal processes, but also lysosome biogenesis, transport, and interaction with other organelles. Using cross-linking mass spectrometry, we analyzed lysosomes and early endosomes. Based on the identification of 5,376 cross-links, we investigated protein-protein interactions and structures of lysosome- and endosome-related proteins. In particular, we present evidence for a tetrameric assembly of the lysosomal hydrolase PPT1 and heterodimeric/- multimeric structures of FLOT1/FLOT2 at lysosomes and early endosomes. For FLOT1-/FLOT2- positive early endosomes, we identified >300 proteins presenting putative cargo, and confirm the latrophilin family of adhesion G protein-coupled receptors as substrates for flotillin-dependent endocytosis.

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Singh, J., Elhabashy, H., Muthukottiappan, P., Stepath, M., Eisenacher, M., Kohlbacher, O., Gieselmann, V., Winter, D.. 2022-01-12. Cross-linking of the Endolysosomal System Reveals Flotillin Structures and Putative Cargo. https://doi.org/10.1101/2022.01.12.475930

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