The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Peter J Cullen - One of the best experts on this subject based on the ideXlab platform.

  • endosomal retrieval of cargo Retromer is not alone
    Trends in Cell Biology, 2018
    Co-Authors: Kerrie E Mcnally, Peter J Cullen
    Abstract:

    Endosomes are major protein sorting stations in cells. Endosomally localised multi-protein complexes sort integral proteins, including signaling receptors, nutrient transporters, adhesion molecules, and lysosomal hydrolase receptors, for lysosomal degradation or conversely for retrieval and subsequent recycling to various membrane compartments. Correct endosomal sorting of these proteins is essential for maintaining cellular homeostasis, with defects in endosomal sorting implicated in various human pathologies including neurodegenerative disorders. Retromer, an ancient multi-protein complex, is essential for the retrieval and recycling of hundreds of transmembrane proteins. While Retromer is a major player in endosomal retrieval and recycling, several studies have recently identified retrieval mechanisms that are independent of Retromer. Here, we review endosomal retrieval complexes, with a focus on recently discovered Retromer-independent mechanisms.

  • Retromer associates with the cytoplasmic amino terminus of polycystin 2
    Journal of Cell Science, 2018
    Co-Authors: Frances C Tilley, Matthew Gallon, Jing Zhou, Chong Luo, Chris M Danson, Peter J Cullen
    Abstract:

    Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic human disease, with around 12.5 million people affected worldwide. ADPKD results from mutations in either PKD1 or PKD2, which encode the atypical G-protein coupled receptor polycystin-1 (PC1) and the transient receptor potential channel polycystin-2 (PC2), respectively. Although altered intracellular trafficking of PC1 and PC2 is an underlying feature of ADPKD, the mechanisms which govern vesicular transport of the polycystins through the biosynthetic and endosomal membrane networks remain to be fully elucidated. Here, we describe an interaction between PC2 and Retromer, a master controller for the sorting of integral membrane proteins through the endo-lysosomal network. We show that association of PC2 with Retromer occurs via a region in the PC2 cytoplasmic amino-terminal domain, independently of the Retromer-binding Wiskott-Aldrich syndrome and scar homologue (WASH) complex. Based on observations that Retromer preferentially interacts with a trafficking population of PC2, and that ciliary levels of PC1 are reduced upon mutation of key residues required for Retromer association in PC2, our data are consistent with the identification of PC2 as a Retromer cargo protein.This article has an associated First Person interview with the first author of the paper.

  • sequence dependent cargo recognition by snx bars mediates Retromer independent transport of ci mpr
    Journal of Cell Biology, 2017
    Co-Authors: Boris Simonetti, Kate J Heesom, Chris M Danson, Peter J Cullen
    Abstract:

    Endosomal recycling of transmembrane proteins requires sequence-dependent recognition of motifs present within their intracellular cytosolic domains. In this study, we have reexamined the role of Retromer in the sequence-dependent endosome-to-trans-Golgi network (TGN) transport of the cation-independent mannose 6-phosphate receptor (CI-MPR). Although the knockdown or knockout of Retromer does not perturb CI-MPR transport, the targeting of the Retromer-linked sorting nexin (SNX)-Bin, Amphiphysin, and Rvs (BAR) proteins leads to a pronounced defect in CI-MPR endosome-to-TGN transport. The Retromer-linked SNX-BAR proteins comprise heterodimeric combinations of SNX1 or SNX2 with SNX5 or SNX6 and serve to regulate the biogenesis of tubular endosomal sorting profiles. We establish that SNX5 and SNX6 associate with the CI-MPR through recognition of a specific WLM endosome-to-TGN sorting motif. From validating the CI-MPR dependency of SNX1/2-SNX5/6 tubular profile formation, we provide a mechanism for coupling sequence-dependent cargo recognition with the biogenesis of tubular profiles required for endosome-to-TGN transport. Therefore, the data presented in this study reappraise Retromer's role in CI-MPR transport.

  • the emerging role of Retromer in neuroprotection
    Current Opinion in Cell Biology, 2017
    Co-Authors: Kirsty J Mcmillan, Hendrick C Korswagen, Peter J Cullen
    Abstract:

    Efficient sorting and transportation of integral membrane proteins, such as ion channels, nutrient transporters, signalling receptors, cell-cell and cell-matrix adhesion molecules is essential for the function of cellular organelles and hence organism development and physiology. Retromer is a master controller of integral membrane protein sorting and transport through one of the major sorting station within eukaryotic cells, the endosomal network. Subtle de-regulation of Retromer is an emerging theme in the pathoetiology of Parkinson's disease. Here we summarise recent advances in defining the neuroprotective role of Retromer and how its de-regulation may contribute to Parkinson's disease by interfering with: lysosomal health and protein degradation, association with accessory proteins including the WASH complex and mitochondrial health.

  • Retromer and sorting nexins in endosomal sorting
    Biochemical Society Transactions, 2015
    Co-Authors: Matthew Gallon, Peter J Cullen
    Abstract:

    The evolutionarily conserved endosomal Retromer complex rescues transmembrane proteins from the lysosomal degradative pathway and facilitates their recycling to other cellular compartments. Retromer functions in conjunction with numerous associated proteins, including select members of the sorting nexin (SNX) family. In the present article, we review the molecular architecture and cellular roles of Retromer and its various functional partners. The endosomal network is a crucial hub in the trafficking of proteins through the cellular endomembrane system. Transmembrane proteins, here termed cargos, enter endosomes by endocytosis from the plasma membrane or by trafficking from the trans-Golgi network (TGN). Endosomal cargo proteins face one of the two fates: retention in the endosome, leading ultimately to lysosomal degradation or export from the endosome for reuse ('recycling'). The balance of protein degradation and recycling is crucial to cellular homoeostasis; inappropriate sorting of proteins to either fate leads to cellular dysfunction. Retromer is an endosome-membrane-associated protein complex central to the recycling of many cargo proteins from endosomes, both to the TGN and the plasma membrane (and other specialized compartments, e.g. lysosome-related organelles). Retromer function is reliant on a number of proteins from the SNX family. In the present article, we discuss this inter-relationship and how defects in Retromer function are increasingly being linked with human disease.

Matthew N.j. Seaman - One of the best experts on this subject based on the ideXlab platform.

  • navigating the controversies of Retromer mediated endosomal protein sorting
    Frontiers in Cell and Developmental Biology, 2021
    Co-Authors: Matthew N.j. Seaman
    Abstract:

    The Retromer complex was first identified more than 20 years ago through studies conducted in the yeast Saccharomyces cerevisiae. Data obtained using many different model systems have revealed that Retromer is a key component of the endosomal protein sorting machinery being necessary for recognition of membrane "cargo" proteins and formation of tubular carriers that function as transport intermediates. Naturally, over the course of time and with literally hundreds of papers published on Retromer, there have arisen disparities, conflicting observations and some controversies as to how Retromer functions in endosomal protein sorting - the most note-worthy being associated with the two activities that define a vesicle coat: cargo selection and vesicle/tubule formation. In this review, we will attempt to chart a course through some of the more fundamental controversies to arrive at a clearer understanding of Retromer.

  • the Retromer complex from genesis to revelations
    Trends in Biochemical Sciences, 2021
    Co-Authors: Matthew N.j. Seaman
    Abstract:

    The Retromer complex has a well-established role in endosomal protein sorting, being necessary for maintaining the dynamic localisation of hundreds of membrane proteins that traverse the endocytic system. Retromer function and dysfunction is linked with neurodegenerative diseases, including Alzheimer's and Parkinson's disease, and many pathogens, both viral and bacterial, exploit or interfere in Retromer function for their own ends. In this review, the history of Retromer is distilled into a concentrated form that spans the identification of Retromer to recent discoveries that have shed new light on how Retromer functions in endosomal protein sorting and why Retromer is increasingly being viewed as a potential therapeutic target in neurodegenerative disease.

  • a bipartite sorting signal ensures specificity of Retromer complex in membrane protein recycling
    Journal of Cell Biology, 2019
    Co-Authors: Sho W Suzuki, Matthew N.j. Seaman, Yashan Chuang, Scott D Emr
    Abstract:

    Retromer is an evolutionarily conserved protein complex, which sorts functionally diverse membrane proteins into recycling tubules/vesicles from the endosome. Many of the identified cargos possess a recycling signal sequence defined as OX[L/M/V], where O is F/Y/W. However, this sequence is present in almost all proteins encoded in the genome. Also, several identified recycling sequences do not follow this rule. How then does Retromer precisely select its cargos? Here, we reveal that an additional motif is also required for cargo retrieval. The two distinct motifs form a bipartite recycling signal recognized by the Retromer subunits, Vps26 and Vps35. Strikingly, Vps26 utilizes different binding sites depending on the cargo, allowing Retromer to recycle different membrane proteins. Thus, Retromer interacts with cargos in a more complex manner than previously thought, which facilitates precise cargo recognition.

  • Inhibition of TBC1D5 activates Rab7a and can enhance the function of the Retromer cargo-selective complex.
    Journal of cell science, 2018
    Co-Authors: Matthew N.j. Seaman, Aamir S. Mukadam, Sophia Y. Breusegem
    Abstract:

    The Retromer complex is a vital component of the endosomal protein sorting machinery necessary for sorting into both the endosome-to-Golgi retrieval pathway and also the endosome-to-cell-surface recycling pathway. Retromer mediates cargo selection through a trimeric complex comprising VPS35, VPS29 and VPS26, which is recruited to endosomes by binding to Rab7a and Snx3. Retromer function is linked to two distinct neurodegenerative diseases, Parkinson's disease and Alzheimer's disease and modulating Retromer function has been proposed as an avenue to explore for a putative therapy in these conditions. We hypothesised that activating Rab7a to promote the recruitment of Retromer to endosomes could positively modulate its activity. Here, we show that inhibition of the GTPase activating protein TBC1D5 can enhance Rab7a activation and lead to a gain of function for Retromer.

  • Retromer mediated endosomal protein sorting all washed up
    Trends in Cell Biology, 2013
    Co-Authors: Matthew N.j. Seaman, Alexis Gautreau, Daniel D. Billadeau
    Abstract:

    Endosomal protein sorting governs the fate of many physiologically important proteins involved in a panoply of cellular functions. Recent discoveries have revealed a vital role for endosomally localised branched actin patches in facilitating protein sorting. The formation of the actin patches has been shown to require the function of the WASH complex - the major endosomal actin polymerisation-promoting complex - which stimulates the activity of the ubiquitously expressed Arp2/3 complex. Another key component of the endosomal protein-sorting machinery is the Retromer complex. Studies now show that Retromer mediates the recruitment of the WASH complex and its regulators to endosomes. In this review, recent progress in understanding the role of the WASH complex along with Retromer in endosomal protein sorting is discussed.

Hendrik C Korswagen - One of the best experts on this subject based on the ideXlab platform.

  • Retromer dependent recycling of the wnt secretion factor wls is dispensable for stem cell maintenance in the mammalian intestinal epithelium
    PLOS ONE, 2013
    Co-Authors: Reinoud E A De Groot, Henner F Farin, Marie Macůrkova, Hans Clevers, Hendrik C Korswagen
    Abstract:

    In C. elegans and Drosophila, Retromer mediated retrograde transport of Wntless (Wls) from endosomes to the trans-Golgi network (TGN) is required for Wnt secretion. When this retrograde transport pathway is blocked, Wls is missorted to lysosomes and degraded, resulting in reduced Wnt secretion and various Wnt related phenotypes. In the mammalian intestine, Wnt signaling is essential to maintain stem cells. This prompted us to ask if Retromer mediated Wls recycling is also important for Wnt signaling and stem cell maintenance in this system. To answer this question, we generated a conditional Vps35fl allele. As Vps35 is an essential subunit of the Retromer complex, this genetic tool allowed us to inducibly interfere with Retromer function in the intestinal epithelium. Using a pan-intestinal epithelial Cre line (Villin-CreERT2), we did not observe defects in crypt or villus morphology after deletion of Vps35 from the intestinal epithelium. Wnt secreted from the mesenchyme of the intestine may compensate for a reduction in epithelial Wnt secretion. To exclude the effect of the mesenchyme, we generated intestinal organoid cultures. Loss of Vps35 in intestinal organoids did not affect the overall morphology of the organoids. We were able to culture Vps35∆/∆ organoids for many passages without Wnt supplementation in the growth medium. However, Wls protein levels were reduced and we observed a subtle growth defect in the Vps35∆/∆ organoids. These results confirm the role of Retromer in the retrograde trafficking of Wls in the intestine, but show that Retromer mediated Wls recycling is not essential to maintain Wnt signaling or stem cell proliferation in the intestinal epithelium.

  • the Retromer coat complex coordinates endosomal sorting and dynein mediated transport with carrier recognition by the trans golgi network
    Developmental Cell, 2009
    Co-Authors: Thomas Wassmer, Martin Harterink, Jan R.t. Van Weering, Naomi Attar, Colin J Traer, Jacqueline Oakley, Bruno Goud, David J Stephens, Paul Verkade, Hendrik C Korswagen
    Abstract:

    Early endosome-to-trans-Golgi network (TGN) transport is organized by the Retromer complex. Consisting of cargo-selective and membrane-bound subcomplexes, Retromer coordinates sorting with membrane deformation and carrier formation. Here, we describe four mammalian Retromers whose membrane-bound subcomplexes contain specific combinations of the sorting nexins (SNX), SNX1, SNX2, SNX5, and SNX6. We establish that Retromer requires a dynamic spatial organization of the endosomal network, which is regulated through association of SNX5/SNX6 with the p150(glued) component of dynactin, an activator of the minus-end directed microtubule motor dynein; an association further defined through genetic studies in C. elegans. Finally, we also establish that the spatial organization of the Retromer pathway is mediated through the association of SNX1 with the proposed TGN-localized tether Rab6-interacting protein-1. These interactions describe fundamental steps in Retromer-mediated transport and establish that the spatial organization of the Retromer network is a critical element required for efficient Retromer-mediated sorting.

  • wnt signaling requires Retromer dependent recycling of mig 14 wntless in wnt producing cells
    Developmental Cell, 2008
    Co-Authors: Peitzu Yang, Magdalena J. Lorenowicz, Marie Silhankova, Marco C. Betist, Damien Coudreuse, Hendrik C Korswagen
    Abstract:

    Wnt proteins are secreted signaling molecules that play a central role in development and adult tissue homeostasis. We have previously shown that Wnt signaling requires Retromer function in Wnt-producing cells. The Retromer is a multiprotein complex that mediates endosome-to-Golgi transport of specific sorting receptors. MIG-14/Wls is a conserved transmembrane protein that binds Wnt and is required in Wnt-producing cells for Wnt secretion. Here, we demonstrate that in the absence of Retromer function, MIG-14/Wls is degraded in lysosomes and becomes limiting for Wnt signaling. We show that Retromer-dependent recycling of MIG-14/Wls is part of a trafficking pathway that retrieves MIG-14/Wls from the plasma membrane. We propose that MIG-14/Wls cycles between the Golgi and the plasma membrane to mediate Wnt secretion. Regulation of this transport pathway may enable Wnt-producing cells to control the range of Wnt signaling in the tissue.

  • wnt gradient formation requires Retromer function in wnt producing cells
    Science, 2006
    Co-Authors: Damien Coudreuse, Marco C. Betist, Giulietta Roel, Olivier Destree, Hendrik C Korswagen
    Abstract:

    Wnt proteins function as morphogens that can form long-range concentration gradients to pattern developing tissues. Here, we show that the Retromer, a multiprotein complex involved in intracellular protein trafficking, is required for long-range signaling of the Caenorhabditis elegans Wnt ortholog EGL-20. The Retromer functions in EGL-20-producing cells to allow the formation of an EGL-20 gradient along the anteroposterior axis. This function is evolutionarily conserved, because Wnt target gene expression is also impaired in the absence of the Retromer complex in vertebrates. These results demonstrate that the ability of Wnt to regulate long-range patterning events is dependent on a critical and conserved function of the Retromer complex within Wnt-producing cells.

Florian Steinberg - One of the best experts on this subject based on the ideXlab platform.

  • control of rab7 activity and localization through the Retromer tbc1d5 complex enables rab7 dependent mitophagy
    The EMBO Journal, 2018
    Co-Authors: Ana Jimenezorgaz, Arunas Kvainickas, Heike Nagele, Jorn Dengjel, Justin Denner, Stefan Eimer, Florian Steinberg
    Abstract:

    Retromer is an endosomal multi-protein complex that organizes the endocytic recycling of a vast range of integral membrane proteins. Here, we establish an additional Retromer function in controlling the activity and localization of the late endosomal small GTPase RAB7. Surprisingly, we found that RAB7 not only decorates late endosomes or lysosomes, but is also present on the endoplasmic reticulum, trans-Golgi network, and mitochondrial membranes, a localization that is maintained by Retromer and the Retromer-associated RAB7-specific GAP TBC1D5. In the absence of either TBC1D5 or Retromer, RAB7 activity state and localization are no longer controlled and hyperactivated RAB7 expands over the entire lysosomal domain. This lysosomal accumulation of hyperactivated RAB7 results in a striking loss of RAB7 mobility and overall depletion of the inactive RAB7 pool on endomembranes. Functionally, we establish that this control of RAB7 activity is not required for the recycling of Retromer-dependent cargoes, but instead enables the correct sorting of the autophagy related transmembrane protein ATG9a and autophagosome formation around damaged mitochondria during Parkin-mediated mitophagy.

  • cargo selective snx bar proteins mediate Retromer trimer independent retrograde transport
    Journal of Cell Biology, 2017
    Co-Authors: Arunas Kvainickas, Ana Jimenezorgaz, Heike Nagele, Jorn Dengjel, Florian Steinberg
    Abstract:

    The Retromer complex, which recycles the cation-independent mannose 6-phosphate receptor (CI-MPR) from endosomes to the trans-Golgi network (TGN), is thought to consist of a cargo-selective VPS26-VPS29-VPS35 trimer and a membrane-deforming subunit of sorting nexin (SNX)-Bin, Amphyphysin, and Rvs (BAR; SNX-BAR) proteins. In this study, we demonstrate that heterodimers of the SNX-BAR proteins, SNX1, SNX2, SNX5, and SNX6, are the cargo-selective elements that mediate the retrograde transport of CI-MPR from endosomes to the TGN independently of the core Retromer trimer. Using quantitative proteomics, we also identify the IGF1R, among more potential cargo, as another SNX5 and SNX6 binding receptor that recycles through SNX-BAR heterodimers, but not via the Retromer trimer, in a ligand- and activation-dependent manner. Overall, our data redefine the mechanics of Retromer-based sorting and call into question whether Retromer indeed functions as a complex of SNX-BAR proteins and the VPS26-VPS29-VPS35 trimer.

  • identification of molecular heterogeneity in snx27 Retromer mediated endosome to plasma membrane recycling
    Journal of Cell Science, 2014
    Co-Authors: Ian J. Mcgough, Matthew Gallon, Florian Steinberg, Ayaka Yatsu, Norihiko Ohbayashi, Kate J Heesom, Mitsunori Fukuda, Peter J Cullen
    Abstract:

    Retromer is a protein assembly that orchestrates the sorting of transmembrane cargo proteins into endosome-to-Golgi and endosome-to-plasma-membrane transport pathways. Here, we have employed quantitative proteomics to define the interactome of human VPS35, the core Retromer component. This has identified a number of new interacting proteins, including ankyrin-repeat domain 50 (ANKRD50), seriologically defined colon cancer antigen 3 (SDCCAG3) and VPS9-ankyrin-repeat protein (VARP, also known as ANKRD27). Depletion of these proteins resulted in trafficking defects of Retromer-dependent cargo, but differential and cargo-specific effects suggested a surprising degree of functional heterogeneity in Retromer-mediated endosome-to-plasma-membrane sorting. Extending this, suppression of the Retromer-associated WASH complex did not uniformly affect Retromer cargo, thereby confirming cargo-specific functions for Retromer-interacting proteins. Further analysis of the Retromer–VARP interaction identified a role for Retromer in endosome-to-melanosome transport. Suppression of VPS35 led to mistrafficking of the melanogenic enzymes, tyrosinase and tryrosine-related protein 1 (Tyrp1), establishing that Retromer acts in concert with VARP in this trafficking pathway. Overall, these data reveal hidden complexities in Retromer-mediated sorting and open up new directions in our molecular understanding of this essential sorting complex.

  • a unique pdz domain and arrestin like fold interaction reveals mechanistic details of endocytic recycling by snx27 Retromer
    Proceedings of the National Academy of Sciences of the United States of America, 2014
    Co-Authors: Matthew Gallon, Florian Steinberg, Richard B Sessions, Rajesh Ghai, Rohan D Teasdale, Brett M Collins, Thomas Clairfeuille, Peter J Cullen
    Abstract:

    The sorting nexin 27 (SNX27)-Retromer complex is a major regulator of endosome-to-plasma membrane recycling of transmembrane cargos that contain a PSD95, Dlg1, zo-1 (PDZ)-binding motif. Here we describe the core interaction in SNX27-Retromer assembly and its functional relevance for cargo sorting. Crystal structures and NMR experiments reveal that an exposed β-hairpin in the SNX27 PDZ domain engages a groove in the arrestin-like structure of the vacuolar protein sorting 26A (VPS26A) Retromer subunit. The structure establishes how the SNX27 PDZ domain simultaneously binds PDZ-binding motifs and Retromer-associated VPS26. Importantly, VPS26A binding increases the affinity of the SNX27 PDZ domain for PDZ- binding motifs by an order of magnitude, revealing cooperativity in cargo selection. With disruption of SNX27 and Retromer function linked to synaptic dysfunction and neurodegenerative disease, our work provides the first step, to our knowledge, in the molecular description of this important sorting complex, and more broadly describes a unique interaction between a PDZ domain and an arrestin-like fold.

  • Retromer binding to fam21 and the wash complex is perturbed by the parkinson disease linked vps35 d620n mutation
    Current Biology, 2014
    Co-Authors: Ian J. Mcgough, Florian Steinberg, Daniel D. Billadeau, Kate J Heesom, Da Jia, Peter A Barbuti, Kirsty J Mcmillan, Alan L Whone, Maeve A Caldwell, Michael K Rosen
    Abstract:

    Retromer is a protein assembly that plays a central role in orchestrating export of transmembrane-spanning cargo proteins from endosomes into retrieval pathways destined for the Golgi apparatus and the plasma membrane [1]. Recently, a specific mutation in the Retromer component VPS35, VPS35(D620N), has linked Retromer dysfunction to familial autosomal dominant and sporadic Parkinson disease [2, 3]. However, the effect of this mutation on Retromer function remains poorly characterized. Here we established that in cells expressing VPS35(D620N) there is a perturbation in endosome-to-TGN transport but not endosome-to-plasma membrane recycling, which we confirm in patient cells harboring the VPS35(D620N) mutation. Through comparative stable isotope labeling by amino acids in cell culture (SILAC)-based analysis of wild-type VPS35 versus the VPS35(D620N) mutant interactomes, we establish that the major defect of the D620N mutation lies in the association to the actin-nucleating Wiskott-Aldrich syndrome and SCAR homolog (WASH) complex. Moreover, using isothermal calorimetry, we establish that the primary defect of the VPS35(D620N) mutant is a 2.2 ± 0.5-fold decrease in affinity for the WASH complex component FAM21. These data define the primary molecular defect in Retromer assembly that arises from the VPS35(D620N) mutation and, by revealing functional effects on Retromer-mediated endosome-to-TGN transport, provide new insight into Retromer deregulation in Parkinson disease.

Brett M Collins - One of the best experts on this subject based on the ideXlab platform.

  • Structure of the membrane-assembled Retromer coat determined by cryo-electron tomography
    Nature, 2018
    Co-Authors: Oleksiy Kovtun, Rohan D Teasdale, Nicholas Ariotti, N. Leneva, D.j. Owen, John A G Briggs, Yury S. Bykov, Miroslava Schaffer, Benjamin D. Engel, Brett M Collins
    Abstract:

    Eukaryotic cells traffic proteins and lipids between different compartments using protein-coated vesicles and tubules. The Retromer complex is required to generate cargo-selective tubulovesicular carriers from endosomal membranes1–3. Conserved in eukaryotes, Retromer controls the cellular localization and homeostasis of hundreds of transmembrane proteins, and its disruption is associated with major neurodegenerative disorders4–7. How Retromer is assembled and how it is recruited to form coated tubules is not known. Here we describe the structure of the Retromer complex (Vps26–Vps29–Vps35) assembled on membrane tubules with the bin/amphiphysin/rvs-domain-containing sorting nexin protein Vps5, using cryo-electron tomography and subtomogram averaging. This reveals a membrane-associated Vps5 array, from which arches of Retromer extend away from the membrane surface. Vps35 forms the ‘legs’ of these arches, and Vps29 resides at the apex where it is free to interact with regulatory factors. The bases of the arches connect to each other and to Vps5 through Vps26, and the presence of the same arches on coated tubules within cells confirms their functional importance. Vps5 binds to Vps26 at a position analogous to the previously described cargo- and Snx3-binding site, which suggests the existence of distinct Retromer-sorting nexin assemblies. The structure provides insight into the architecture of the coat and its mechanism of assembly, and suggests that Retromer promotes tubule formation by directing the distribution of sorting nexin proteins on the membrane surface while providing a scaffold for regulatory-protein interactions.

  • parkinson disease linked vps35 r524w mutation impairs the endosomal association of Retromer and induces α synuclein aggregation
    Journal of Biological Chemistry, 2016
    Co-Authors: Jordan Follett, Brett M Collins, Suzanne J Norwood, Zhe Yang, Nicholas Ariotti, Robert G Parton, Andrea Bugarcic, Rohan D Teasdale
    Abstract:

    Endosomal sorting is a highly orchestrated cellular process. Retromer is a heterotrimeric complex that associates with endosomal membranes and facilitates the retrograde sorting of multiple receptors, including the cation-independent mannose 6-phosphate receptor for lysosomal enzymes. The cycling of Retromer on and off the endosomal membrane is regulated by a network of Retromer-interacting proteins. Here, we find that Parkinson disease-associated Vps35 variant, R524W, but not P316S, is a loss-of-function mutation as marked by a reduced association with this regulatory network and dysregulation of endosomal receptor sorting. Expression of Vps35 R524W-containing Retromer results in the accumulation of intracellular α-synuclein-positive aggregates, a hallmark of Parkinson disease. Overall, the Vps35 R524W-containing Retromer has a decreased endosomal association, which can be partially rescued by R55, a small molecule previously shown to stabilize the Retromer complex, supporting the potential for future targeting of the Retromer complex in the treatment of Parkinson disease.

  • sorting nexin 27 couples pthr trafficking to Retromer for signal regulation in osteoblasts during bone growth
    Molecular Biology of the Cell, 2016
    Co-Authors: Audrey S M Chan, Rohan D Teasdale, Thomas Clairfeuille, Wanjin Hong, Euphemie Landaobassonga, Genevieve Kinna, Li Shen Loo, Tak Sum Cheng, Minghao Zheng, Brett M Collins
    Abstract:

    The parathyroid hormone 1 receptor (PTHR) is central to the process of bone formation and remodeling. PTHR signaling requires receptor internalization into endosomes, which is then terminated by recycling or degradation. Here we show that sorting nexin 27 (SNX27) functions as an adaptor that couples PTHR to the Retromer trafficking complex. SNX27 binds directly to the C-terminal PDZ-binding motif of PTHR, wiring it to Retromer for endosomal sorting. The structure of SNX27 bound to the PTHR motif reveals a high-affinity interface involving conserved electrostatic interactions. Mechanistically, depletion of SNX27 or Retromer augments intracellular PTHR signaling in endosomes. Osteoblasts genetically lacking SNX27 show similar disruptions in PTHR signaling and greatly reduced capacity for bone mineralization, contributing to profound skeletal deficits in SNX27-knockout mice. Taken together, our data support a critical role for SNX27-Retromer mediated transport of PTHR in normal bone development.

  • a unique pdz domain and arrestin like fold interaction reveals mechanistic details of endocytic recycling by snx27 Retromer
    Proceedings of the National Academy of Sciences of the United States of America, 2014
    Co-Authors: Matthew Gallon, Florian Steinberg, Richard B Sessions, Rajesh Ghai, Rohan D Teasdale, Brett M Collins, Thomas Clairfeuille, Peter J Cullen
    Abstract:

    The sorting nexin 27 (SNX27)-Retromer complex is a major regulator of endosome-to-plasma membrane recycling of transmembrane cargos that contain a PSD95, Dlg1, zo-1 (PDZ)-binding motif. Here we describe the core interaction in SNX27-Retromer assembly and its functional relevance for cargo sorting. Crystal structures and NMR experiments reveal that an exposed β-hairpin in the SNX27 PDZ domain engages a groove in the arrestin-like structure of the vacuolar protein sorting 26A (VPS26A) Retromer subunit. The structure establishes how the SNX27 PDZ domain simultaneously binds PDZ-binding motifs and Retromer-associated VPS26. Importantly, VPS26A binding increases the affinity of the SNX27 PDZ domain for PDZ- binding motifs by an order of magnitude, revealing cooperativity in cargo selection. With disruption of SNX27 and Retromer function linked to synaptic dysfunction and neurodegenerative disease, our work provides the first step, to our knowledge, in the molecular description of this important sorting complex, and more broadly describes a unique interaction between a PDZ domain and an arrestin-like fold.

  • assembly and solution structure of the core Retromer protein complex
    Traffic, 2011
    Co-Authors: Suzanne J Norwood, Rohan D Teasdale, D.j. Owen, Daniel J Shaw, Nathan Cowieson, Brett M Collins
    Abstract:

    Retromer is a peripheral membrane protein complex that has pleiotropic roles in endosomal membrane trafficking. The core of Retromer possesses three subunits, VPS35, VPS29 and VPS26, that play different roles in binding to cargo, regulatory proteins and complex stabilization. We have performed an investigation of the thermodynamics of core Retromer assembly using isothermal titration calorimetry (ITC) demonstrating that VPS35 acts as the central subunit to which VPS29 and VPS26 bind independently. Furthermore, we confirm that the conserved PRLYL motif of the large VPS35 subunit is critical for direct VPS26 interaction. Heat capacity measurements of VPS29 and VPS26 binding to VPS35 indicate extensive binding interfaces and suggest conformational alterations in VPS29 or VPS35 upon complex formation. Solution studies of the Retromer core using small-angle X-ray scattering allow us to propose a model whereby VPS35 forms an extended platform with VPS29 and VPS26 bound at distal ends, with the potential for forming dimeric assemblies.