Structural organization of the retriever–CCC endosomal recycling complex

Abstract

The recycling of membrane proteins from endosomes to the cell surface is vital for cell signaling and survival. Retriever, a trimeric complex of VPS35L, VPS26C and VPS29, together with the CCC complex comprising CCDC22, CCDC93, and COMMD proteins, plays a crucial role in this process. The precise mechanisms underlying Retriever assembly and its interaction with CCC have remained elusive. Here, we present the first high-resolution structure of Retriever determined using cryogenic electron microscopy. The structure reveals a unique assembly mechanism, distinguishing it from its remotely related paralog, Retromer. By combining AlphaFold predictions and biochemical, cellular, and proteomic analyses, we further elucidate the structural organization of the entire Retriever-CCC complex and uncover how cancerassociated mutations disrupt complex formation and impair membrane protein homeostasis.These findings provide a fundamental framework for understanding the biological and pathological implications associated with Retriever-CCC-mediated endosomal recycling.

Endosomal protein DENND10/FAM45A integrates extracellular vesicle release with cancer cell migration

“…Consistently, DENND10 knockout was phenotypically similar to Rab27a knockdown cells in multiple aspects, including accumulation of lysosomal proteins [ 49 ], reduction of EV release [ 50 ], and impaired migration [ 48 ]. Additionally, several recent structural studies [ 12 – 14 ] identified DENND10 as an integral subunit of the CCC-Retriever (Commander) endosomal complexes, a highly conserved protein machinery involved in endosomal sorting and recycling [ 51 , 52 ]. We have confirmed this interaction ourselves (manuscript in preparation).…”

“…Human DENND10 protein shares 69.0% sequence similarity with its orthologue in amoeba ( Dictyostelium discoideum ) [ 11 ], suggesting conserved function(s) from unicellular organisms to vertebrates. Several recent structural studies have demonstrated that DENND10 is an integral subunit within the CCC/Retriever complexes (also called the Commander complex) in the endosomal recycling pathway [ 12 – 14 ]. However, no physiological roles for DENND10 have been described so far.…”

Mechanism and regulation of cargo entry into the Commander recycling pathway

“…The copyright holder for this preprint this version posted January 11, 2024. ; https://doi.org/10.1101/2024.01.10.574988 doi: bioRxiv preprint Retriever is assembled around a central VPS35L subunit to which VPS26C and VPS29 associate at spatially distant amino-and carboxy-terminal regions of the VPS35L asolenoid (Fig. 1B) (Boesch et al, 2023;Healy et al, 2023;Laulumaa et al, 2023). We employed AlphaFold2 modelling (Jumper et al, 2021;Mirdita et al, 2022) to predict the association between Retriever and the unstructured human SNX17 tail corresponding to residues Gly400-to-Leu470.…”

“…Central to network function are multi-protein complexes that coordinate sequence-dependent recognition of integral proteins with the biogenesis of vesicular and tubular transport carriers (McNally and Cullen, 2018; Chen et al, 2019; McDonald, 2021). Retriever is an essential cargo sorting complex and is a stable heterotrimer of VPS26C, VPS35L and VPS29, that together with the dodecameric CCDC22, CCDC93, COMMD (CCC) complex and DENND10, forms the 16-subunit Commander super-assembly (Phillips-Krawczak et al, 2015; Mallam and Marcotte, 2017; McNally et al, 2017; Boesch et al, 2023; Healy et al, 2023; Laulumaa et al, 2023). Defects in Commander assembly and function are associated with metabolic disorders including hypercholesterolemia (Bartuzi et al, 2016; Fedoseienko et al, 2018; Rimbert et al, 2020; Vos et al, 2023), viral infection (Daniloski et al, 2021; Zhu et al, 2021), and lead to Ritscher-Schinzel syndrome, a multi-system developmental disorder characterized by abnormal craniofacial features, cerebellar hypoplasia, and stunted cardiovascular development (Kolanczyk et al, 2015; Kato et al, 2020; Otsuji et al, 2023).…”

Monocytic Differentiation of Human Acute Myeloid Leukemia Cells: A Proteomic and Phosphoproteomic Comparison of FAB-M4/M5 Patients with and without Nucleophosmin 1 Mutations

“…• Clathrin. Another small network included the clathrin interactor 1 (CLINT1), clathrin light chain beta (CLTB), and aftiphilin (AFTPH) (Table 2 and S3) [37,38,[51][52][53][54][55][56][57][58][59][60][61][62][63][64]. Clathrinmediated endocytosis is important for cellular nutrition as well as receptor-mediated endocytosis, membrane recycling, and control of signal pathways [26,30].…”