scholarly journals Cargo-selective SNX-BAR proteins mediate retromer trimer independent retrograde transport

2017 ◽  
Vol 216 (11) ◽  
pp. 3677-3693 ◽  
Author(s):  
Arunas Kvainickas ◽  
Ana Jimenez-Orgaz ◽  
Heike Nägele ◽  
Zehan Hu ◽  
Jörn Dengjel ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Retrograde Transport ◽  
Dependent Manner ◽  
Sorting Nexin ◽  
Trans Golgi Network ◽  
The Core ◽  
Retromer Complex ◽  
Mannose 6 Phosphate ◽  
Golgi Network

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.

scholarly journals Retromer retrieves the Wilson disease protein ATP7B from endolysosomes in a copper-dependent manner

2020 ◽  
Vol 133 (24) ◽  
pp. jcs246819 ◽  
Author(s):  
Santanu Das ◽  
Saptarshi Maji ◽  
Ruturaj ◽  
Indira Bhattacharya ◽  
Tanusree Saha ◽  
...  
Keyword(s):  
Wilson Disease ◽  
Dependent Manner ◽  
Copper Transporter ◽  
Copper Chelation ◽  
Trans Golgi Network ◽  
Wilson Disease Protein ◽  
Retromer Complex ◽  
High Copper ◽  
Disease Protein ◽  
Golgi Network

ABSTRACTThe Wilson disease protein, ATP7B maintains copper (herein referring to the Cu+ ion) homeostasis in the liver. ATP7B traffics from trans-Golgi network to endolysosomes to export excess copper. Regulation of ATP7B trafficking to and from endolysosomes is not well understood. We investigated the fate of ATP7B after copper export. At high copper levels, ATP7B traffics primarily to acidic, active hydrolase (cathepsin-B)-positive endolysosomes and, upon subsequent copper chelation, returns to the trans-Golgi network (TGN). At high copper, ATP7B colocalizes with endolysosomal markers and with a core member of retromer complex, VPS35. Knocking down VPS35 did not abrogate the copper export function of ATP7B or its copper-responsive anterograde trafficking to vesicles; rather upon subsequent copper chelation, ATP7B failed to relocalize to the TGN, which was rescued by overexpressing wild-type VPS35. Overexpressing mutants of the retromer complex-associated proteins Rab7A and COMMD1 yielded a similar non-recycling phenotype of ATP7B. At high copper, VPS35 and ATP7B are juxtaposed on the same endolysosome and form a large complex that is stabilized by in vivo photoamino acid labeling and UV-crosslinking. We demonstrate that retromer regulates endolysosome to TGN trafficking of copper transporter ATP7B in a manner that is dependent upon intracellular copper.

scholarly journals Interchangeable but Essential Functions of SNX1 and SNX2 in the Association of Retromer with Endosomes and the Trafficking of Mannose 6-Phosphate Receptors

2006 ◽  
Vol 27 (3) ◽  
pp. 1112-1124 ◽  
Author(s):  
Raul Rojas ◽  
Satoshi Kametaka ◽  
Carol R. Haft ◽  
Juan S. Bonifacino
Keyword(s):  
Mammalian Cells ◽  
Human Cell Line ◽  
Sorting Nexin ◽  
Retromer Complex ◽  
Cell Line Hela ◽  
Endosomal Membranes ◽  
Mannose 6 Phosphate ◽  
And Function ◽  
Golgi Network ◽  
Functional Analyses

ABSTRACT The retromer is a cytosolic/peripheral membrane protein complex that mediates the retrieval of the cation-independent mannose 6-phosphate receptor from endosomes to the trans-Golgi network (TGN) in mammalian cells. Previous studies showed that the mammalian retromer comprises three proteins, named Vps26, Vps29, and Vps35, plus the sorting nexin, SNX1. There is conflicting evidence, however, as to whether a homologous sorting nexin, SNX2, is truly a component of the retromer. In addition, the nature of the subunit interactions and assembly of the mammalian retromer complex are poorly understood. We have addressed these issues by performing biochemical and functional analyses of endogenous retromers in the human cell line HeLa. We found that the mammalian retromer complex consists of two autonomously assembling subcomplexes, namely, a Vps26-Vps29-Vps35 obligate heterotrimer and a SNX1/2 alternative heterodimer or homodimer. The association of Vps26-Vps29-Vps35 with endosomes requires the presence of either SNX1 or SNX2, whereas SNX1/2 can be recruited to endosomes independently of Vps26-Vps29-Vps35. We also found that the presence of either SNX1 or SNX2 is essential for the retrieval of the cation-independent mannose 6-phosphate receptor to the TGN. These observations indicate that the mammalian retromer complex assembles by sequential association of SNX1/2 and Vps26-Vps29-Vps35 subcomplexes on endosomal membranes and that SNX1 and SNX2 play interchangeable but essential roles in retromer structure and function.

scholarly journals Regulation of retromer recruitment to endosomes by sequential action of Rab5 and Rab7

2008 ◽  
Vol 183 (3) ◽  
pp. 513-526 ◽  
Author(s):  
Raul Rojas ◽  
Thijs van Vlijmen ◽  
Gonzalo A. Mardones ◽  
Yogikala Prabhu ◽  
Adriana L. Rojas ◽  
...  
Keyword(s):  
Cathepsin D ◽  
Retrograde Transport ◽  
Phosphatidylinositol 3 Kinase ◽  
Sorting Nexin ◽  
Retromer Complex ◽  
Endosomal Membranes ◽  
Guanosine Triphosphatase ◽  
Vacuolar Protein ◽  
Golgi Network ◽  
Phosphatidylinositol 3

The retromer complex mediates retrograde transport of transmembrane cargo from endosomes to the trans-Golgi network (TGN). Mammalian retromer is composed of a sorting nexin (SNX) dimer that binds to phosphatidylinositol 3-phosphate–enriched endosomal membranes and a vacuolar protein sorting (Vps) 26/29/35 trimer that participates in cargo recognition. The mammalian SNX dimer is necessary but not sufficient for recruitment of the Vps26/29/35 trimer to membranes. In this study, we demonstrate that the guanosine triphosphatase Rab7 contributes to this recruitment. The Vps26/29/35 trimer specifically binds to Rab7–guanosine triphosphate (GTP) and localizes to Rab7-containing endosomal domains. Interference with Rab7 function causes dissociation of the Vps26/29/35 trimer but not the SNX dimer from membranes. This blocks retrieval of mannose 6-phosphate receptors to the TGN and impairs cathepsin D sorting. Rab5-GTP does not bind to the Vps26/29/35 trimer, but perturbation of Rab5 function causes dissociation of both the SNX and Vps26/29/35 components from membranes through inhibition of a pathway involving phosphatidylinositol 3-kinase. These findings demonstrate that Rab5 and Rab7 act in concert to regulate retromer recruitment to endosomes.

scholarly journals The Golgin GCC88 Is Required for Efficient Retrograde Transport of Cargo from the Early Endosomes to the Trans-Golgi Network

2007 ◽  
Vol 18 (12) ◽  
pp. 4979-4991 ◽  
Author(s):  
Zi Zhao Lieu ◽  
Merran C. Derby ◽  
Rohan D. Teasdale ◽  
Charles Hart ◽  
Priscilla Gunn ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Retrograde Transport ◽  
Transport Pathway ◽  
Transport Pathways ◽  
Recycling Endosomes ◽  
Trans Golgi Network ◽  
Early Endosomes ◽  
Cargo Proteins ◽  
Mannose 6 Phosphate ◽  
Golgi Network

Retrograde transport pathways from early/recycling endosomes to the trans-Golgi network (TGN) are poorly defined. We have investigated the role of TGN golgins in retrograde trafficking. Of the four TGN golgins, p230/golgin-245, golgin-97, GCC185, and GCC88, we show that GCC88 defines a retrograde transport pathway from early endosomes to the TGN. Depletion of GCC88 in HeLa cells by interference RNA resulted in a block in plasma membrane–TGN recycling of two cargo proteins, TGN38 and a CD8 mannose-6-phosphate receptor cytoplasmic tail fusion protein. In GCC88-depleted cells, cargo recycling was blocked in the early endosome. Depletion of GCC88 dramatically altered the TGN localization of the t-SNARE syntaxin 6, a syntaxin required for endosome to TGN transport. Furthermore, the transport block in GCC88-depleted cells was rescued by syntaxin 6 overexpression. Internalized Shiga toxin was efficiently transported from endosomes to the Golgi of GCC88-depleted cells, indicating that Shiga toxin and TGN38 are internalized by distinct retrograde transport pathways. These findings have identified an essential role for GCC88 in the localization of TGN fusion machinery for transport from early endosomes to the TGN, and they have allowed the identification of a retrograde pathway which differentially selects TGN38 and mannose-6-phosphate receptor from Shiga toxin.

scholarly journals Lysosomal Hydrolase Mannose 6-Phosphate Uncovering Enzyme Resides in the trans-Golgi Network

2001 ◽  
Vol 12 (6) ◽  
pp. 1623-1631 ◽  
Author(s):  
Jack Rohrer ◽  
Rosalind Kornfeld
Keyword(s):  
Plasma Membrane ◽  
Fluorescent Protein ◽  
Lysosomal Hydrolases ◽  
Intracellular Location ◽  
Trans Golgi Network ◽  
Cytosolic Domain ◽  
Cytosolic Domains ◽  
Mannose 6 Phosphate ◽  
Green Fluorescent ◽  
Golgi Network

A crucial step in lysosomal biogenesis is catalyzed by “uncovering” enzyme (UCE), which removes a coveringN-acetylglucosamine from the mannose 6-phosphate (Man-6-P) recognition marker on lysosomal hydrolases. This study shows that UCE resides in the trans-Golgi network (TGN) and cycles between the TGN and plasma membrane. The cytosolic domain of UCE contains two potential endocytosis motifs: 488YHPL and C-terminal 511NPFKD. YHPL is shown to be the more potent of the two in retrieval of UCE from the plasma membrane. A green-fluorescent protein-UCE transmembrane-cytosolic domain fusion protein colocalizes with TGN 46, as does endogenous UCE in HeLa cells, showing that the transmembrane and cytosolic domains determine intracellular location. These data imply that the Man-6-P recognition marker is formed in the TGN, the compartment where Man-6-P receptors bind cargo and are packaged into clathrin-coated vesicles.

GGA proteins regulate retrograde transport of BACE1 from endosomes to the trans-Golgi network

2005 ◽  
Vol 29 (3) ◽  
pp. 453-461 ◽  
Author(s):  
Tina Wahle ◽  
Kai Prager ◽  
Nikolai Raffler ◽  
Christian Haass ◽  
Michael Famulok ◽  
...  
Keyword(s):  
Retrograde Transport ◽  
Trans Golgi Network ◽  
Golgi Network

scholarly journals Yeast synaptobrevin, Snc1, engages distinct routes of postendocytic recycling mediated by a sorting nexin, Rcy1-COPI, and retromer

2020 ◽  
Vol 31 (9) ◽  
pp. 944-962
Author(s):  
Jordan T. Best ◽  
Peng Xu ◽  
Jack G. McGuire ◽  
Shannon N. Leahy ◽  
Todd R. Graham
Keyword(s):  
Plasma Membrane ◽  
Multiple Modes ◽  
Sorting Nexin ◽  
Trans Golgi Network ◽  
Golgi Network

The yeast synaptobrevin, Snc1, uses multiple modes of postendocytic recycling to facilitate its return to either the trans-Golgi network or the plasma membrane. Snc1 primarily recycles via pathways dependent on either Rcy1/COPI or Snx4, while a smaller portion of the SNARE appears to be capable of being retrieved by retromer.

scholarly journals Sorting nexin 27 rescues neuroligin 2 from lysosomal degradation to control inhibitory synapse number

2019 ◽  
Vol 476 (2) ◽  
pp. 293-306 ◽  
Author(s):  
Caroline S. Binda ◽  
Yasuko Nakamura ◽  
Jeremy M. Henley ◽  
Kevin A. Wilkinson
Keyword(s):  
Adaptor Protein ◽  
Inhibitory Synapse ◽  
Endosomal Trafficking ◽  
Dependent Manner ◽  
Lysosomal Degradation ◽  
Sorting Nexin ◽  
The Core ◽  
Cargo Proteins ◽  
Vacuolar Protein ◽  
Zona Occludens

Abstract Retromer is an evolutionarily conserved endosomal trafficking complex that mediates the retrieval of cargo proteins from a degradative pathway for sorting back to the cell surface. To promote cargo recycling, the core retromer trimer of VPS (vacuolar protein sorting)26, VPS29 and VPS35 recognises cargo either directly, or through an adaptor protein, the most well characterised of which is the PDZ [postsynaptic density 95 (PSD95), disk large, zona occludens] domain-containing sorting nexin SNX27. Neuroligins (NLGs) are postsynaptic trans-synaptic scaffold proteins that function in the clustering of postsynaptic proteins to maintain synaptic stability. Here, we show that each of the NLGs (NLG1–3) bind to SNX27 in a direct PDZ ligand-dependent manner. Depletion of SNX27 from neurons leads to a decrease in levels of each NLG protein and, for NLG2, this occurs as a result of enhanced lysosomal degradation. Notably, while depletion of the core retromer component VPS35 leads to a decrease in NLG1 and NLG3 levels, NLG2 is unaffected, suggesting that, for this cargo, SNX27 acts independently of retromer. Consistent with loss of SNX27 leading to enhanced lysosomal degradation of NLG2, knockdown of SNX27 results in fewer NLG2 clusters in cultured neurons, and loss of SNX27 or VPS35 reduces the size and number of gephyrin clusters. Together, these data indicate that NLGs are SNX27–retromer cargoes and suggest that SNX27–retromer controls inhibitory synapse number, at least in part through trafficking of NLG2.

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