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

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 a heterodimeric structure of FLOT1/FLOT2 at lysosomes and early endosomes. For FLOT1-/FLOT2-positive early endosomes, we identified >300 proteins presenting putative cargo, and confirmed several substrates for flotillin-dependent endocytosis, including the latrophilin family of adhesion G protein-coupled receptors.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Jasjot Singh

LAB HEAD: Dominic Winter

PROVIDER: PXD030532 | Pride | 2022-10-22

REPOSITORIES: Pride

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