Article

Horazdovsky, B. F. et al. A sorting nexin-1 homologue, Vps5p, forms a complex with Vps17p and is required for recycling the vacuolar protein-sorting receptor. Mol. Biol. Cell 8, 1529-1541

Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235-9038, USA.
Molecular Biology of the Cell (Impact Factor: 4.47). 09/1997; 8(8):1529-41. DOI: 10.1091/mbc.8.8.1529
Source: PubMed

ABSTRACT

A number of the Saccharomyces cerevisiae vacuolar protein-sorting (vps) mutants exhibit an altered vacuolar morphology. Unlike wild-type cells that contain 1-3 large vacuolar structures, the class B vps5 and vps17 mutant cells contain 10-20 smaller vacuole-like compartments. To explore the role of these VPS gene products in vacuole biogenesis, we cloned and sequenced VPS5 and characterized its protein products. The VPS5 gene is predicted to encode a very hydrophilic protein of 675 amino acids that shows significant sequence homology with mammalian sorting nexin-1. Polyclonal antiserum directed against the VPS5 gene product detects a single, cytoplasmic protein that is phosphorylated specifically on a serine residue(s). Subcellular fractionation studies indicate that Vps5p is associated peripherally with a dense membrane fraction distinct from Golgi, endosomal, and vacuolar membranes. This association was found to be dependent on the presence of another class B VPS gene product, Vps17p. Biochemical cross-linking studies demonstrated that Vps5p and Vps17p physically interact. Gene disruption experiments show that the VPS5 genes product is not essential for cell viability; however, cells carrying the null allele contain fragmented vacuoles and exhibit defects in vacuolar protein-sorting similar to vps17 null mutants. More than 95% of carboxypeptidase Y is secreted from these cells in its Golgi-modified p2 precursor form. Additionally, the Vps10p vacuolar protein-sorting receptor is mislocalized to the vacuole in vps5 mutant cells. On the basis of these and other observations, we propose that the Vps17p protein complex may participate in the intracellular trafficking of the Vps10p-sorting receptor, as well as other later-Golgi proteins.

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Available from: Matthew Seaman, Feb 26, 2014
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    • "Pioneering studies of protein sorting in the yeast endolysosomal system led to the identification of an endosomal coat protein complex named " retromer " that was found to be required for retrieval of a TGN sorting receptor (Vps10) from the endosome to the TGN (Seaman et al. 1998). The initial biochemical characterization of yeast retromer showed that it is composed of five proteins that can be dissociated into two subcomplexes (Horazdovsky et al. 1997; Seaman et al. 1997, 1998). One subcomplex contains a heterodimer of the Vps5 and Vps17 sorting nexins (SNX), which possess Bin/Amphiphysin/ Rvs (BAR) domains (SNX-BAR proteins) that can induce and/or sense the formation of membrane tubules (Carlton et al. 2004; van Weering et al. 2012a). "
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    ABSTRACT: The endosomal network comprises an interconnected network of membranous compartments whose primary function is to receive, dissociate, and sort cargo that originates from the plasma membrane and the biosynthetic pathway. A major challenge in cell biology is to achieve a thorough molecular description of how this network operates, and in so doing, how defects contribute to the etiology and pathology of human disease. We discuss the increasing body of evidence that implicates an ancient evolutionary conserved complex, termed "retromer," as a master conductor in the complex orchestration of multiple cargo-sorting events within the endosomal network.
    Preview · Article · Feb 2014 · Cold Spring Harbor perspectives in biology
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    • "In retromer-mediated endosomal protein sorting in mammalian cells, Snx1 and Snx2 are functionally interchangeable (Rojas et al., 2007; Schwarz et al., 2002). Both form heterodimers with Snx5 and Snx6, which are equivalent to the Vps5p–Vps17p dimer that constitutes the Snx-BAR retromer component in yeast (Wassmer et al., 2007; Horazdovsky et al., 1997). Snx5 and Snx6 functionally link retromer-mediated endosomal protein sorting to the dynein complex through an interaction with p150-glued (also known as dynactin subunit 1, DCTN1), thereby mechanistically interfacing with the microtubule cytoskeleton (Wassmer et al., 2009; Hong et al., 2009). "
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    ABSTRACT: The retromer complex is a vital element of the endosomal protein sorting machinery that is conserved across all eukaryotes. Retromer is most closely associated with the endosome-to-Golgi retrieval pathway and is necessary to maintain an active pool of hydrolase receptors in the trans-Golgi network. Recent progress in studies of retromer have identified new retromer-interacting proteins, including the WASH complex and cargo such as the Wntless/MIG-14 protein, which now extends the role of retromer beyond the endosome-to-Golgi pathway and has revealed that retromer is required for aspects of endosome-to-plasma membrane sorting and regulation of signalling events. The interactions between the retromer complex and other macromolecular protein complexes now show how endosomal protein sorting is coordinated with actin assembly and movement along microtubules, and place retromer squarely at the centre of a complex set of protein machinery that governs endosomal protein sorting. Dysregulation of retromer-mediated endosomal protein sorting leads to various pathologies, including neurodegenerative diseases such as Alzheimer disease and spastic paraplegia and the mechanisms underlying these pathologies are starting to be understood. In this Commentary, I will highlight recent advances in the understanding of retromer-mediated endosomal protein sorting and discuss how retromer contributes to a diverse set of physiological processes.
    Full-text · Article · Nov 2012 · Journal of Cell Science
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    • "Some of the possible targets of PI3P during sporulation have been identified, including two sorting nexins, Vps5 and Vps17, and the FYVE domain–containing protein Sst4/Vps27. Vps5 and Vps17 have a phox homology (PX) domain, and analysis of homologues of these proteins in S. cerevisiae suggests that Vps5 and Vps17 in S. pombe act as PI3P-dependent mediators of retrograde trafficking from the endosome to the Golgi apparatus, which in turn acts as an efficient anterograde membrane flux to the FSM (Horazdovsky et al., 1997; Pfeffer, 2001; Onishi et al., 2003a; Koga et al., 2004). In contrast, Sst4 functions at later stages of FSM formation, specifically when the FSM closes (Onishi et al., 2007). "
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