scholarly journals The Oxysterol-binding Protein Homologue ORP1L Interacts with Rab7 and Alters Functional Properties of Late Endocytic Compartments

2005 ◽  
Vol 16 (12) ◽  
pp. 5480-5492 ◽  
Author(s):  
Marie Johansson ◽  
Markku Lehto ◽  
Kimmo Tanhuanpää ◽  
Timothy L. Cover ◽  
Vesa M. Olkkonen
Keyword(s):  
Membrane Trafficking ◽  
Binding Protein ◽  
Pleckstrin Homology Domain ◽  
Rab Gtpases ◽  
Microtubule Network ◽  
Oxysterol Binding Protein ◽  
Motor Complex ◽  
Late Endosomes ◽  
Endocytic Compartments ◽  
Fluorescent Dextran

ORP1L is a member of the human oxysterol-binding protein (OSBP) family. ORP1L localizes to late endosomes (LEs)/lysosomes, colocalizing with the GTPases Rab7 and Rab9 and lysosome-associated membrane protein-1. We demonstrate that ORP1L interacts physically with Rab7, preferentially with its GTP-bound form, and provide evidence that ORP1L stabilizes GTP-bound Rab7 on LEs/lysosomes. The Rab7-binding determinant is mapped to the ankyrin repeat (ANK) region of ORP1L. The pleckstrin homology domain (PHD) of ORP1L binds phosphoinositides with low affinity and specificity. ORP1L ANK- and ANK+PHD fragments induce perinuclear clustering of LE/lysosomes. This is dependent on an intact microtubule network and a functional dynein/dynactin motor complex. The dominant inhibitory Rab7 mutant T22N reverses the LE clustering, suggesting that the effect is dependent on active Rab7. Transport of fluorescent dextran to LEs is inhibited by overexpression of ORP1L. Overexpression of ORP1L, and in particular the N-terminal fragments of ORP1L, inhibits vacuolation of LE caused by Helicobacter pylori toxin VacA, a process also involving Rab7. The present study demonstrates that ORP1L binds to Rab7, modifies its functional cycle, and can interfere with LE/lysosome organization and endocytic membrane trafficking. This is the first report of a direct connection between the OSBP-related protein family and the Rab GTPases.

scholarly journals The Two Variants of Oxysterol Binding Protein-related Protein-1 Display Different Tissue Expression Patterns, Have Different Intracellular Localization, and Are Functionally Distinct

2003 ◽  
Vol 14 (3) ◽  
pp. 903-915 ◽  
Author(s):  
Marie Johansson ◽  
Virginie Bocher ◽  
Markku Lehto ◽  
Giulia Chinetti ◽  
Esa Kuismanen ◽  
...  
Keyword(s):  
Binding Protein ◽  
Expression Patterns ◽  
Intracellular Localization ◽  
Tissue Expression ◽  
Ankyrin Repeat ◽  
Pleckstrin Homology Domain ◽  
Related Protein ◽  
Amino Terminal ◽  
Oxysterol Binding Protein ◽  
Late Endosomes

Oxysterol binding protein (OSBP) homologs comprise a family of 12 proteins in humans ( Jaworski et al., 2001 ; Lehtoet al., 2001 ). Two variants of OSBP-related protein (ORP) 1 have been identified: a short one that consists of the carboxy-terminal ligand binding domain only (ORP1S, 437 aa) and a longer N-terminally extended form (ORP1L, 950 aa) encompassing three ankyrin repeats and a pleckstrin homology domain (PHD). We now report that the two mRNAs show marked differences in tissue expression. ORP1S predominates in skeletal muscle and heart, whereas ORP1L is the most abundant form in brain and lung. On differentiation of primary human monocytes into macrophages, both ORP1S and ORP1L mRNAs were induced, the up-regulation of ORP1L being >100-fold. The intracellular localization of the two ORP1 variants was found to be different. Whereas ORP1S is largely cytosolic, the ORP1L variant localizes to late endosomes. A significant amount of ORP1S but only little ORP1L was found in the nucleus. The ORP1L ankyrin repeat region (aa 1–237) was found to localize to late endosomes such as the full-length protein. This localization was even more pronounced for a fragment that additionally includes the PHD (aa 1–408). The amino-terminal region of ORP1L consisting of the ankyrin repeat and PHDs is therefore likely to be responsible for the targeting of ORP1L to late endosomes. Interestingly, overexpression of ORP1L was found to enhance the LXRα-mediated transactivation of a reporter gene, whereas ORP1S failed to influence this process. The results suggest that the two forms of ORP1 are functionally distinct and that ORP1L is involved in control of cellular lipid metabolism.

scholarly journals A role for oxysterol-binding protein–related protein 5 in endosomal cholesterol trafficking

2011 ◽  
Vol 192 (1) ◽  
pp. 121-135 ◽  
Author(s):  
Ximing Du ◽  
Jaspal Kumar ◽  
Charles Ferguson ◽  
Timothy A. Schulz ◽  
Yan Shan Ong ◽  
...  
Keyword(s):  
Binding Protein ◽  
Lipid Binding ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Oxysterol Binding Protein ◽  
Late Endosomes ◽  
Evolutionarily Conserved ◽  
Niemann Pick ◽  
Related Proteins ◽  
Lipid Binding Proteins

Oxysterol-binding protein (OSBP) and its related proteins (ORPs) constitute a large and evolutionarily conserved family of lipid-binding proteins that target organelle membranes to mediate sterol signaling and/or transport. Here we characterize ORP5, a tail-anchored ORP protein that localizes to the endoplasmic reticulum. Knocking down ORP5 causes cholesterol accumulation in late endosomes and lysosomes, which is reminiscent of the cholesterol trafficking defect in Niemann Pick C (NPC) fibroblasts. Cholesterol appears to accumulate in the limiting membranes of endosomal compartments in ORP5-depleted cells, whereas depletion of NPC1 or both ORP5 and NPC1 results in luminal accumulation of cholesterol. Moreover, trans-Golgi resident proteins mislocalize to endosomal compartments upon ORP5 depletion, which depends on a functional NPC1. Our results establish the first link between NPC1 and a cytoplasmic sterol carrier, and suggest that ORP5 may cooperate with NPC1 to mediate the exit of cholesterol from endosomes/lysosomes.

scholarly journals Phagosomes Fuse with Late Endosomes and/or Lysosomes by Extension of Membrane Protrusions along Microtubules: Role of Rab7 and RILP

2003 ◽  
Vol 23 (18) ◽  
pp. 6494-6506 ◽  
Author(s):  
Rene E. Harrison ◽  
Cecilia Bucci ◽  
Otilia V. Vieira ◽  
Trina A. Schroer ◽  
Sergio Grinstein
Keyword(s):  
Innate Immune ◽  
Effector Protein ◽  
Motor Complex ◽  
Fluorescence And Electron Microscopy ◽  
Late Endosomes ◽  
Membrane Protrusions ◽  
Endocytic Compartments ◽  
Phagosomal Membrane ◽  
Lysosomal Protein

ABSTRACT Nascent phagosomes must undergo a series of fusion and fission reactions to acquire the microbicidal properties required for the innate immune response. Here we demonstrate that this maturation process involves the GTPase Rab7. Rab7 recruitment to phagosomes was found to precede and to be essential for their fusion with late endosomes and/or lysosomes. Active Rab7 on the phagosomal membrane associates with the effector protein RILP (Rab7-interacting lysosomal protein), which in turn bridges phagosomes with dynein-dynactin, a microtubule-associated motor complex. The motors not only displace phagosomes in the centripetal direction but, strikingly, promote the extension of phagosomal tubules toward late endocytic compartments. Fusion of tubules with these organelles was documented by fluorescence and electron microscopy. Tubule extension and fusion with late endosomes and/or lysosomes were prevented by expression of a truncated form of RILP lacking the dynein-dynactin-recruiting domain. We conclude that full maturation of phagosomes requires the retrograde emission of tubular extensions, which are generated by activation of Rab7, recruitment of RILP, and consequent association of phagosomes with microtubule-associated motors.

scholarly journals The oxysterol-binding protein superfamily: new concepts and old proteins

2012 ◽  
Vol 40 (2) ◽  
pp. 469-473 ◽  
Author(s):  
Michelle L. Villasmil ◽  
Vytas A. Bankaitis ◽  
Carl J. Mousley
Keyword(s):  
Lipid Metabolism ◽  
Membrane Trafficking ◽  
Transcriptional Control ◽  
Binding Protein ◽  
Lipid Binding ◽  
Oxysterol Binding Protein ◽  
New Concepts ◽  
Endosomal Membranes ◽  
Phosphatidylinositol 4 ◽  
Golgi Network

The Kes1 OSBP (oxysterol-binding protein) is a key regulator of membrane trafficking through the TGN (trans-Golgi network) and endosomal membranes. We demonstrated recently that Kes1 acts as a sterol-regulated rheostat for TGN/endosomal phosphatidylinositol 4-phosphate signalling. Kes1 utilizes its dual lipid-binding activities to integrate endosomal lipid metabolism with TORC1 (target of rapamycin complex 1)-dependent proliferative pathways and transcriptional control of nutrient signalling.

scholarly journals Dynein-mediated Vesicle Transport Controls Intracellular Salmonella Replication

2004 ◽  
Vol 15 (6) ◽  
pp. 2954-2964 ◽  
Author(s):  
Marije Marsman ◽  
Ingrid Jordens ◽  
Coen Kuijl ◽  
Lennert Janssen ◽  
Jacques Neefjes
Keyword(s):  
Hela Cells ◽  
Small Gtpase ◽  
Vesicle Transport ◽  
Endocytic Pathway ◽  
Rab Gtpases ◽  
Intracellular Replication ◽  
Motor Complex ◽  
Late Endosomes ◽  
Membrane Bound ◽  
Gtpase Cycle

Salmonella typhimurium survives and replicates intracellular in a membrane-bound compartment, the Salmonella-containing vacuole (SCV). In HeLa cells, the SCV matures through interactions with the endocytic pathway, but Salmonella avoids fusion with mature lysosomes. The exact mechanism of the inhibition of phagolysosomal fusion is not understood. Rab GTPases control several proteins involved in membrane fusion and vesicular transport. The small GTPase Rab7 regulates the transport of and fusion between late endosomes and lysosomes and associates with the SCV. We show that the Rab7 GTPase cycle is not affected on the SCV. We then manipulated a pathway downstream of the small GTPase Rab7 in HeLa cells infected with Salmonella. Expression of the Rab7 effector RILP induces recruitment of the dynein/dynactin motor complex to the SCV. Subsequently, SCV fuse with lysosomes. As a result, the intracellular replication of Salmonella is inhibited. Activation of dynein-mediated vesicle transport can thus control intracellular survival of Salmonella.

PI4P/PS countertransport by ORP10 at ER–endosome membrane contact sites regulates endosome fission

2021 ◽  
Vol 221 (1) ◽  
Author(s):  
Asami Kawasaki ◽  
Akiko Sakai ◽  
Hiroki Nakanishi ◽  
Junya Hasegawa ◽  
Tomohiko Taguchi ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Binding Protein ◽  
Dependent Manner ◽  
Oxysterol Binding Protein ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Lipid Exchange ◽  
Membrane Contact ◽  
Phosphatidylinositol 4

Membrane contact sites (MCSs) serve as a zone for nonvesicular lipid transport by oxysterol-binding protein (OSBP)-related proteins (ORPs). ORPs mediate lipid countertransport, in which two distinct lipids are transported counterdirectionally. How such lipid countertransport controls specific biological functions, however, remains elusive. We report that lipid countertransport by ORP10 at ER–endosome MCSs regulates retrograde membrane trafficking. ORP10, together with ORP9 and VAP, formed ER–endosome MCSs in a phosphatidylinositol 4-phosphate (PI4P)-dependent manner. ORP10 exhibited a lipid exchange activity toward its ligands, PI4P and phosphatidylserine (PS), between liposomes in vitro, and between the ER and endosomes in situ. Cell biological analysis demonstrated that ORP10 supplies a pool of PS from the ER, in exchange for PI4P, to endosomes where the PS-binding protein EHD1 is recruited to facilitate endosome fission. Our study highlights a novel lipid exchange at ER–endosome MCSs as a nonenzymatic PI4P-to-PS conversion mechanism that organizes membrane remodeling during retrograde membrane trafficking.

scholarly journals Activation of endosomal dynein motors by stepwise assembly of Rab7–RILP–p150Glued, ORP1L, and the receptor βlll spectrin

2007 ◽  
Vol 176 (4) ◽  
pp. 459-471 ◽  
Author(s):  
Marie Johansson ◽  
Nuno Rocha ◽  
Wilbert Zwart ◽  
Ingrid Jordens ◽  
Lennert Janssen ◽  
...  
Keyword(s):  
Small Gtpase ◽  
Related Protein ◽  
Oxysterol Binding Protein ◽  
Dynein Motor ◽  
Microtubule Motors ◽  
Late Endosomes ◽  
Endocytic Compartments ◽  
Stepwise Assembly ◽  
Motor Recruitment ◽  
Lysosomal Protein

The small GTPase Rab7 controls late endocytic transport by the minus end–directed motor protein complex dynein–dynactin, but how it does this is unclear. Rab7-interacting lysosomal protein (RILP) and oxysterol-binding protein–related protein 1L (ORP1L) are two effectors of Rab7. We show that GTP-bound Rab7 simultaneously binds RILP and ORP1L to form a RILP–Rab7–ORP1L complex. RILP interacts directly with the C-terminal 25-kD region of the dynactin projecting arm p150Glued, which is required for dynein motor recruitment to late endocytic compartments (LEs). Still, p150Glued recruitment by Rab7–RILP does not suffice to induce dynein-driven minus-end transport of LEs. ORP1L, as well as βIII spectrin, which is the general receptor for dynactin on vesicles, are essential for dynein motor activity. Our results illustrate that the assembly of microtubule motors on endosomes involves a cascade of linked events. First, Rab7 recruits two effectors, RILP and ORP1L, to form a tripartite complex. Next, RILP directly binds to the p150Glued dynactin subunit to recruit the dynein motor. Finally, the specific dynein motor receptor Rab7–RILP is transferred by ORP1L to βIII spectrin. Dynein will initiate translocation of late endosomes to microtubule minus ends only after interacting with βIII spectrin, which requires the activities of Rab7–RILP and ORP1L.

ER–endosome contact sites in endosome positioning and protrusion outgrowth

2016 ◽  
Vol 44 (2) ◽  
pp. 441-446 ◽  
Author(s):  
Camilla Raiborg ◽  
Eva M. Wenzel ◽  
Nina M. Pedersen ◽  
Harald Stenmark
Keyword(s):  
Endoplasmic Reticulum ◽  
Binding Protein ◽  
Cell Periphery ◽  
Related Protein ◽  
Gear Shift ◽  
Oxysterol Binding Protein ◽  
Contact Sites ◽  
Late Endosomes ◽  
Microtubule Motor ◽  
Cholesterol Binding

The endoplasmic reticulum (ER) makes abundant contacts with endosomes, and the numbers of contact sites increase as endosomes mature. It is already clear that such contact sites have diverse compositions and functions, but in this mini-review we will focus on two particular types of ER–endosome contact sites that regulate endosome positioning. Formation of ER–endosome contact sites that contain the cholesterol-binding protein oxysterol-binding protein-related protein 1L (ORP1L) is coordinated with loss of the minus-end-directed microtubule motor Dynein from endosomes. Conversely, formation of ER–endosome contact sites that contain the Kinesin-1-binding protein Protrudin results in transfer of the plus-end-directed microtubule motor Kinesin-1 from ER to endosomes. We discuss the possibility that formation of these two types of contact sites is coordinated as a ‘gear-shift’ mechanism for endosome motility, and we review evidence that Kinesin-1-mediated motility of late endosomes (LEs) to the cell periphery promotes outgrowth of neurites and other protrusions.

scholarly journals The mammalian oxysterol-binding protein-related proteins (ORPs) bind 25-hydroxycholesterol in an evolutionarily conserved pocket

2007 ◽  
Vol 405 (3) ◽  
pp. 473-480 ◽  
Author(s):  
Monika Suchanek ◽  
Riikka Hynynen ◽  
Gerd Wohlfahrt ◽  
Markku Lehto ◽  
Marie Johansson ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Structural Model ◽  
Binding Protein ◽  
Site Directed Mutagenesis ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Oxysterol Binding Protein ◽  
Related Proteins ◽  
Sterol Binding

OSBP (oxysterol-binding protein) homologues, ORPs (OSBP-related proteins), constitute a 12-member family in mammals. We employed an in vitro [3H]25OH (25-hydroxycholesterol)-binding assay with purified recombinant proteins as well as live cell photo-cross-linking with [3H]photo-25OH and [3H]photoCH (photo-cholesterol), to investigate sterol binding by the mammalian ORPs. ORP1 and ORP2 [a short ORP consisting of an ORD (OSBP-related ligand-binding domain) only] were in vitro shown to bind 25OH. GST (glutathione S-transferase) fusions of the ORP1L [long variant with an N-terminal extension that carries ankyrin repeats and a PH domain (pleckstrin homology domain)] and ORP1S (short variant consisting of an ORD only) variants bound 25OH with similar affinity (ORP1L, Kd=9.7×10−8 M; ORP1S, Kd=8.4 ×10−8 M), while the affinity of GST–ORP2 for 25OH was lower (Kd=3.9×10−6 M). Molecular modelling suggested that ORP2 has a sterol-binding pocket similar to that of Saccharomyces cerevisiae Osh4p. This was confirmed by site-directed mutagenesis of residues in proximity of the bound sterol in the structural model. Substitution of Ile249 by tryptophan or Lys150 by alanine markedly inhibited 25OH binding by ORP2. In agreement with the in vitro data, ORP1L, ORP1S, and ORP2 were cross-linked with photo-25OH in live COS7 cells. Furthermore, in experiments with either truncated cDNAs encoding the OSBP-related ligand-binding domains of the ORPs or the full-length proteins, photo-25OH was bound to OSBP, ORP3, ORP4, ORP5, ORP6, ORP7, ORP8, ORP10 and ORP11. In addition, the ORP1L variant and ORP3, ORP5, and ORP8 were cross-linked with photoCH. The present study identifies ORP1 and ORP2 as OSBPs and suggests that most of the mammalian ORPs are able to bind sterols.

scholarly journals Oxysterol-binding protein-related protein 1 variants have opposing cholesterol transport activities from the endolysosomes

2020 ◽  
Vol 31 (8) ◽  
pp. 793-802 ◽  
Author(s):  
Kexin Zhao ◽  
Jason Foster ◽  
Neale D. Ridgway
Keyword(s):  
Plasma Membrane ◽  
Cholesterol Efflux ◽  
Binding Protein ◽  
Ldl Receptor ◽  
Full Length ◽  
Receptor Activity ◽  
Cholesterol Transport ◽  
Related Protein ◽  
Oxysterol Binding Protein ◽  
Late Endosomes

OSBPL1 encodes the full-length ORP1L and the truncated variant ORP1S. ORP1S is responsible for transferring cholesterol from late endosomes to the plasma membrane to regulate cholesterol efflux by ABCA1 and LDL receptor activity. ORP1L and ORP1S combine to transport cholesterol from late endosomes to the ER and PM, respectively.

Sign in / Sign up

Export Citation Format

Share Document