PT  - JOURNAL ARTICLE
AU  - Singh, Jasjot
AU  - Elhabashy, Hadeer
AU  - Muthukottiappan, Pathma
AU  - Stepath, Markus
AU  - Eisenacher, Martin
AU  - Kohlbacher, Oliver
AU  - Gieselmann, Volkmar
AU  - Winter, Dominic
TI  - Cross-linking of the Endolysosomal System Reveals Flotillin Structures and Putative Cargo
AID  - 10.1101/2022.01.12.475930
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.01.12.475930
4099  - http://biorxiv.org/content/early/2022/01/12/2022.01.12.475930.short
4100  - http://biorxiv.org/content/early/2022/01/12/2022.01.12.475930.full
AB  - 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.Competing Interest StatementThe authors have declared no competing interest.