scholarly journals Translocation of oxysterol binding protein to Golgi apparatus triggered by ligand binding.

1992 ◽  
Vol 116 (2) ◽  
pp. 307-319 ◽  
Author(s):  
N D Ridgway ◽  
P A Dawson ◽  
Y K Ho ◽  
M S Brown ◽  
J L Goldstein
Keyword(s):  
Golgi Apparatus ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Brefeldin A ◽  
Sterol Metabolism ◽  
Animal Cells ◽  
Transfected Cells ◽  
Oxysterol Binding Protein ◽  
Golgi Membranes ◽  
Lentil Lectin

A cDNA encoding a cytoplasmic oxysterol binding protein was expressed at high levels by transfection in animal cells. This protein binds oxysterols such as 25-hydroxycholesterol that regulate sterol metabolism by transcriptional and posttranscriptional effects. In the transfected cells, some of the oxysterol binding protein (OSBP) was distributed diffusely in the cytoplasm, and some was bound to small vesicles near the nucleus, as revealed by indirect immunofluorescence. Upon addition of 25-hydroxycholesterol, most of the OSBP became concentrated in large perinuclear structures that stained with lentil lectin, a protein that stains the Golgi apparatus. The structures that contained OSBP were disrupted by brefeldin A, confirming their identification as Golgi. A mutant OSBP lacking the COOH-terminal oxysterol binding domain localized to the Golgi spontaneously, suggesting that this domain normally occludes the domain that binds to the Golgi and that sterols relieve this occlusion. The previously noted potential leucine zipper sequence in OSBP was not required for Golgi localization, nor was it essential for homodimer formation. We conclude that OSBP is triggered to bind extrinsically to Golgi membranes when it binds oxysterols and speculate that this translocation may play a role in the transport, metabolism, or regulatory actions of oxysterols.

scholarly journals cDNA cloning and expression of oxysterol-binding protein, an oligomer with a potential leucine zipper

1989 ◽  
Vol 264 (28) ◽  
pp. 16798-16803
Author(s):  
P A Dawson ◽  
N D Ridgway ◽  
C A Slaughter ◽  
M S Brown ◽  
J L Goldstein
Keyword(s):  
Cdna Cloning ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Cloning And Expression ◽  
Oxysterol Binding Protein

scholarly journals Brefeldin A inhibits transport of the glycophorin-binding protein from Plasmodium falciparum into the host erythrocyte

1994 ◽  
Vol 300 (3) ◽  
pp. 821-826 ◽  
Author(s):  
J Benting ◽  
D Mattei ◽  
K Lingelbach
Keyword(s):  
Plasmodium Falciparum ◽  
Golgi Apparatus ◽  
Host Cell ◽  
Protein Secretion ◽  
Secretory Pathway ◽  
Binding Protein ◽  
Brefeldin A ◽  
Cell Cytoplasm ◽  
Parasite Cell ◽  
Host Cell Cytoplasm

Plasmodium falciparum, a protozoan parasite of the human erythrocyte, causes the most severe form of malaria. During its intraerythrocytic development, the parasite synthesizes proteins which are exported into the host cell. The compartments involved in the secretory pathway of P. falciparum are still poorly characterized. A Golgi apparatus has not been identified, owing to the lack of specific protein markers and Golgi-specific post-translational modifications in the parasite. The fungal metabolite brefeldin A (BFA) is known to inhibit protein secretion in higher eukaryotes by disrupting the integrity of the Golgi apparatus. We have used the parasite-encoded glycophorin-binding protein (GBP), a soluble protein found in the host cell cytoplasm, as a marker to investigate the effects of BFA on protein secretion in the intracellular parasite. In the presence of BFA, GBP was not transported into the erythrocyte, but remained inside the parasite cell. The effect caused by BFA was reversible, and the protein could be chased into the host cell cytoplasm within 30 min. Transport of GBP from the BFA-sensitive site into the host cell did not require protein synthesis. Similar observations were made when infected erythrocytes were incubated at 15 degrees C. Incubation at 20 degrees C resulted in a reduction rather than a complete block of protein export. The relevance of our findings to the identification of compartments involved in protein secretion from the parasite cell is discussed.

scholarly journals The Golgi Apparatus Maintains Its Organization Independent of the Endoplasmic Reticulum

2006 ◽  
Vol 17 (12) ◽  
pp. 5372-5380 ◽  
Author(s):  
Matthew Y. Pecot ◽  
Vivek Malhotra
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Binding Protein ◽  
Physiological Conditions ◽  
Fk506 Binding Protein ◽  
Golgi Membranes ◽  
Intermediate Compartment ◽  
Tight Association

Under artificial conditions Golgi enzymes have the capacity to rapidly accumulate in the endoplasmic reticulum (ER). These observations prompted the idea that Golgi enzymes constitutively recycle through the ER. We have tested this hypothesis under physiological conditions through use of a procedure that captures Golgi enzymes in the ER. In the presence of rapamycin, which induces a tight association between FKBP (FK506-binding protein) and FRAP (FKBP-rapamycin–associated protein), an FKBP-tagged Golgi enzyme can be trapped when it visits the ER by an ER-retained protein fused to FRAP. We find that although FKBP-ERGIC-53 of the ER-Golgi intermediate compartment (ERGIC) rapidly cycles through the ER (30 min), FKBP-Golgi enzyme chimeras remain stably associated with Golgi membranes. We also demonstrate that Golgi dispersion upon nocodazole treatment mainly occurs through a mechanism that does not involve the recycling of Golgi membranes through the ER. Our findings suggest that the Golgi apparatus, as defined by its collection of resident enzymes, exists independent of the ER.

scholarly journals Family of human oxysterol binding protein (OSBP) homologues: a novel member implicated in brain sterol metabolism

1999 ◽  
Vol 40 (12) ◽  
pp. 2204-2211 ◽  
Author(s):  
Saara Laitinen ◽  
Vesa M. Olkkonen ◽  
Christian Ehnholm ◽  
Elina Ikonen
Keyword(s):  
Binding Protein ◽  
Sterol Metabolism ◽  
Oxysterol Binding Protein

scholarly journals Role of Oxysterol Binding Protein in Hepatitis C Virus infection

2009 ◽  
Vol 83 (18) ◽  
pp. 9237-9246 ◽  
Author(s):  
Yutaka Amako ◽  
Ali Sarkeshik ◽  
Hak Hotta ◽  
John Yates ◽  
Aleem Siddiqui
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Golgi Apparatus ◽  
Binding Protein ◽  
Hcv Rna ◽  
Ph Domain ◽  
Particle Release ◽  
Oxysterol Binding Protein ◽  
Rnp Complex

ABSTRACT Hepatitis C virus (HCV) RNA genome replicates within the ribonucleoprotein (RNP) complex in the modified membranous structures extended from endoplasmic reticulum. A proteomic analysis of HCV RNP complexes revealed the association of oxysterol binding protein (OSBP) as one of the components of these complexes. OSBP interacted with the N-terminal domain I of the HCV NS5A protein and colocalized to the Golgi compartment with NS5A. An OSBP-specific short hairpin RNA that partially downregulated OSBP expression resulted in a decrease of the HCV particle release in culture supernatant with little effect on viral RNA replication. The pleckstrin homology (PH) domain located in the N-terminal region of OSBP targeted this protein to the Golgi apparatus. OSBP deletion mutation in the PH (ΔPH) domain failed to localize to the Golgi apparatus and inhibited the HCV particle release. These studies suggest a possible functional role of OSBP in the HCV maturation process.

Brefeldin A affects the endomembrane system and vesicle trafficking in higher plants

1993 ◽  
Vol 51 ◽  
pp. 192-193
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Jancy Henderson ◽  
David Evans ◽  
Kim Crooks ◽  
Mark Fricker ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Higher Plants ◽  
Fatty Acid Derivative ◽  
Plant Cells ◽  
Brefeldin A ◽  
Endomembrane System ◽  
Animal Cells ◽  
Higher Plant ◽  
Membrane Flow ◽  
Golgi Stack

In plant cells, as in animal cells, many macromolecules and membranes are transported by vesicle vectors through both the exocytotic and endocytotic pathways. In order to elucidate the mechanisms and molecular events of such trafficking we are using a set of drugs known to perturb membrane flow in plant cells in combination with immunocytochemical studies using a bank of monoclonal antibodies to various components of the endomembrane system and cell surface. In animal cells, one such drug, Brefeldin A, a fungal fatty acid derivative which causes disruption of the Golgi apparatus, has recently been used as a tool to dissect the mechanisms of vesicle flow from the endoplasmic reticulum to the Golgi apparatus and down the cisternae of the Golgi stack (1). It has been demonstrated that BFA also has a dramatic effect on the Golgi apparatus in higher plant cells (2,3,4).In this paper we report on recent work on the disruption of the plant Golgi apparatus with BFA and the redistribution of endomembrane marker epitopes after drug treatment of roots and suspension culture cells.

scholarly journals Cholesterol regulates oxysterol binding protein (OSBP) phosphorylation and Golgi localization in Chinese hamster ovary cells: correlation with stimulation of sphingomyelin synthesis by 25-hydroxycholesterol

1998 ◽  
Vol 336 (1) ◽  
pp. 247-256 ◽  
Author(s):  
Margo K. STOREY ◽  
David M. BYERS ◽  
Harold W. COOK ◽  
Neale D. RIDGWAY
Keyword(s):  
Golgi Apparatus ◽  
Chinese Hamster Ovary ◽  
Binding Protein ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Density Lipoprotein ◽  
Cholesterol Content ◽  
Cholesterol Depletion ◽  
Experimental Conditions ◽  
Oxysterol Binding Protein

Sphingomyelin (SM) and cholesterol content is positively correlated in cellular membranes, and in several pathological and experimental conditions there is evidence for coregulation. The potential role of oxysterols and oxysterol binding protein (OSBP) in mediating the coregulation of cholesterol and SM was examined using Chinese hamster ovary (CHO) and cholesterol auxotrophic, sterol regulatory defective (SRD) 6 cells. SRD 6 cells grown in the presence or absence of cholesterol for 24 h displayed a 30–50% reduction in SM synthesis compared with control CHO 7 cells. SM synthesis in CHO 7 and cholesterol-supplemented SRD 6 cells was stimulated 2-fold by 25-hydroxycholesterol, but cholesterol-starved SRD 6 cells were unresponsive. Basal and 25-hydroxycholesterol-stimulated SM synthesis was also inhibited in lovastatin-treated wild-type CHO-K1 cells. Lack of 25-hydroxycholesterol activation of SM synthesis in cholesterol-starved SRD 6 and lovastatin-treated CHO-K1 cells was correlated with dephosphorylation of OSBP. In SRD 6 cells, this was evident after 12 h of cholesterol depletion, it occurred equally at all phosphorylation sites and was exacerbated by 25-hydroxycholesterol. Unlike CHO 7 cells, where OSBP was observed in small vesicles and the cytoplasm, OSBP in cholesterol-starved SRD 6 cells was constitutively localized in the Golgi apparatus. Supplementation with non-lipoprotein cholesterol promoted redistribution to vesicles and the cytoplasm. Similarly, OSBP in CHO-K1 cells grown in delipidated serum was predominantly in the Golgi apparatus. Low-density lipoprotein (LDL) supplementation of CHO-K1 cells caused the redistribution of OSBP to the cytoplasm and small vesicles, and this effect was blocked by pharmacological agents {3-β-[2-(diethylamino)ethoxy]androst-5-en-17-one and progesterone}, which inhibited LDL cholesterol efflux from lysosomes. The results showed that localization of OSBP between the Golgi apparatus and a cytoplasmic/vesicular compartment was responsive to changes in cholesterol content and trafficking. In cholesterol depleted SRD 6 cells, this was accompanied by dephosphorylation of OSBP and attenuation of 25-hydroxycholesterol activation of SM synthesis.

scholarly journals Role of NAD+ and ADP-Ribosylation in the Maintenance of the Golgi Structure

1997 ◽  
Vol 139 (5) ◽  
pp. 1109-1118 ◽  
Author(s):  
Alexander Mironov ◽  
Antonino Colanzi ◽  
Maria Giuseppina Silletta ◽  
Giusy Fiucci ◽  
Silvio Flati ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Golgi Complex ◽  
Brefeldin A ◽  
Coat Proteins ◽  
Cytosolic Proteins ◽  
Permeabilized Cells ◽  
Adp Ribosylation ◽  
Golgi Membranes ◽  
Golgi Structure

We have investigated the role of the ADP- ribosylation induced by brefeldin A (BFA) in the mechanisms controlling the architecture of the Golgi complex. BFA causes the rapid disassembly of this organelle into a network of tubules, prevents the association of coatomer and other proteins to Golgi membranes, and stimulates the ADP-ribosylation of two cytosolic proteins of 38 and 50 kD (GAPDH and BARS-50; De Matteis, M.A., M. DiGirolamo, A. Colanzi, M. Pallas, G. Di Tullio, L.J. McDonald, J. Moss, G. Santini, S. Bannykh, D. Corda, and A. Luini. 1994. Proc. Natl. Acad. Sci. USA. 91:1114–1118; Di Girolamo, M., M.G. Silletta, M.A. De Matteis, A. Braca, A. Colanzi, D. Pawlak, M.M. Rasenick, A. Luini, and D. Corda. 1995. Proc. Natl. Acad. Sci. USA. 92:7065–7069). To study the role of ADP-ribosylation, this reaction was inhibited by depletion of NAD+ (the ADP-ribose donor) or by using selective pharmacological blockers in permeabilized cells. In NAD+-depleted cells and in the presence of dialized cytosol, BFA detached coat proteins from Golgi membranes with normal potency but failed to alter the organelle's structure. Readdition of NAD+ triggered Golgi disassembly by BFA. This effect of NAD+ was mimicked by the use of pre–ADP- ribosylated cytosol. The further addition of extracts enriched in native BARS-50 abolished the ability of ADP-ribosylated cytosol to support the effect of BFA. Pharmacological blockers of the BFA-dependent ADP-ribosylation (Weigert, R., A. Colanzi, A. Mironov, R. Buccione, C. Cericola, M.G. Sciulli, G. Santini, S. Flati, A. Fusella, J. Donaldson, M. DiGirolamo, D. Corda, M.A. De Matteis, and A. Luini. 1997. J. Biol. Chem. 272:14200–14207) prevented Golgi disassembly by BFA in permeabilized cells. These inhibitors became inactive in the presence of pre–ADP-ribosylated cytosol, and their activity was rescued by supplementing the cytosol with a native BARS-50–enriched fraction. These results indicate that ADP-ribosylation plays a role in the Golgi disassembling activity of BFA, and suggest that the ADP-ribosylated substrates are components of the machinery controlling the structure of the Golgi apparatus.

scholarly journals Oxysterol-binding Protein and Vesicle-associated Membrane Protein–associated Protein Are Required for Sterol-dependent Activation of the Ceramide Transport Protein

2006 ◽  
Vol 17 (6) ◽  
pp. 2604-2616 ◽  
Author(s):  
Ryan J. Perry ◽  
Neale D. Ridgway
Keyword(s):  
Golgi Apparatus ◽  
Membrane Protein ◽  
Binding Protein ◽  
Chinese Hamster ◽  
Transport Protein ◽  
Cholesterol Homeostasis ◽  
Membrane Microdomains ◽  
Cholesterol Depletion ◽  
Oxysterol Binding Protein ◽  
293 Cells

Sphingomyelin (SM) and cholesterol are coregulated metabolically and associate physically in membrane microdomains involved in cargo sorting and signaling. One mechanism for regulation of this metabolic interface involves oxysterol binding protein (OSBP) via high-affinity binding to oxysterol regulators of cholesterol homeostasis and activation of SM synthesis at the Golgi apparatus. Here, we show that OSBP regulation of SM synthesis involves the endoplasmic reticulum (ER)-to-Golgi ceramide transport protein (CERT). RNA interference (RNAi) experiments in Chinese hamster ovary (CHO)-K1 cells revealed that OSBP and vesicle-associated membrane protein–associated protein (VAP) were required for stimulation of CERT-dependent ceramide transport and SM synthesis by 25-hydroxycholesterol and cholesterol depletion in response to cyclodextrin. Additional RNAi experiments in human embryonic kidney 293 cells supported OSBP involvement in oxysterol-activated SM synthesis and also revealed a role for OSBP in basal SM synthesis. Activation of ER-to-Golgi ceramide transport in CHO-K1 cells required interaction of OSBP with the ER and Golgi apparatus, OSBP-dependent Golgi translocation of CERT, and enhanced CERT–VAP interaction. Regulation of CERT by OSBP, sterols, and VAP reveals a novel mechanism for integrating sterol regulatory signals with ceramide transport and SM synthesis in the Golgi apparatus.

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