scholarly journals GOLPH3 and GOLPH3L are broad-spectrum COPI adaptors for sorting into intra-Golgi transport vesicles

2021 ◽  
Author(s):  
Lawrence G Welch ◽  
Sew-Yeu Peak-Chew ◽  
Farida Begum ◽  
Tim J Stevens ◽  
Sean Munro
Keyword(s):  
Wide Spectrum ◽  
Binding Studies ◽  
Diverse Range ◽  
Golgi Stack ◽  
Golgi Transport ◽  
Transport Vesicles ◽  
Golgi Retention ◽  
Cytoplasmic Tails

Glycosylation is a diverse and abundant modification of proteins, lipids and RNA. The fidelity of glycosylation is, in part, assured by the correct compartmentalisation of Golgi-resident glycosylation enzymes within the Golgi stack. The COPI adaptor GOLPH3 has been shown to interact with the cytoplasmic tails of a subset of Golgi enzymes and direct their retention in the Golgi. However, other mechanisms of retention, and other roles for GOLPH3, have been proposed, and a comprehensive characterisation of the clientele of GOLPH3 and its paralogue GOLPH3L has been lacking. The role of GOLPH3 is of particular interest as it is frequently amplified in several solid tumour types. Here, we combine two orthogonal proteomic analyses to identify a diverse range of GOLPH3+3L clients and find that they act in a wide spectrum of glycosylation pathways, or have other roles in the Golgi. Using binding studies, bioinformatics and an in vivo Golgi retention assay, we show that GOLPH3+3L interact with the cytoplasmic tails of their clients through membrane-proximal positively-charged residues. Furthermore, deletion of GOLPH3+3L causes diverse defects in glycosylation. Thus, GOLPH3+3L are major COPI adaptors that impinge on most, if not all, of the glycosylation pathways of the Golgi.

scholarly journals GOLPH3 and GOLPH3L are broad-spectrum COPI adaptors for sorting into intra-Golgi transport vesicles

2021 ◽  
Vol 220 (10) ◽  
Author(s):  
Lawrence G. Welch ◽  
Sew-Yeu Peak-Chew ◽  
Farida Begum ◽  
Tim J. Stevens ◽  
Sean Munro
Keyword(s):  
Binding Studies ◽  
Golgi Transport ◽  
Transport Vesicles ◽  
Golgi Retention ◽  
Cytoplasmic Tails ◽  
Tumor Types ◽  
Comprehensive Characterization ◽  
Positively Charged ◽  
Proteomic Methods

The fidelity of Golgi glycosylation is, in part, ensured by compartmentalization of enzymes within the stack. The COPI adaptor GOLPH3 has been shown to interact with the cytoplasmic tails of a subset of Golgi enzymes and direct their retention. However, other mechanisms of retention, and other roles for GOLPH3, have been proposed, and a comprehensive characterization of the clientele of GOLPH3 and its paralogue GOLPH3L is lacking. GOLPH3’s role is of particular interest as it is frequently amplified in several solid tumor types. Here, we apply two orthogonal proteomic methods to identify GOLPH3+3L clients and find that they act in diverse glycosylation pathways or have other roles in the Golgi. Binding studies, bioinformatics, and a Golgi retention assay show that GOLPH3+3L bind the cytoplasmic tails of their clients through membrane-proximal positively charged residues. Furthermore, deletion of GOLPH3+3L causes multiple defects in glycosylation. Thus, GOLPH3+3L are major COPI adaptors that impinge on most, if not all, of the glycosylation pathways of the Golgi.

scholarly journals Mycobacterium abscessuscording prevents phagocytosis and promotes abscess formation

2014 ◽  
Vol 111 (10) ◽  
pp. E943-E952 ◽  
Author(s):  
Audrey Bernut ◽  
Jean-Louis Herrmann ◽  
Karima Kissa ◽  
Jean-François Dubremetz ◽  
Jean-Louis Gaillard ◽  
...  
Keyword(s):  
Immune Evasion ◽  
Wide Spectrum ◽  
Mycobacterium Abscessus ◽  
Abscess Formation ◽  
Zebrafish Embryos ◽  
Clinical Syndromes ◽  
The Central Nervous System ◽  
Underlying Mechanisms

Mycobacterium abscessusis a rapidly growingMycobacteriumcausing a wide spectrum of clinical syndromes. It now is recognized as a pulmonary pathogen to which cystic fibrosis patients have a particular susceptibility. TheM. abscessusrough (R) variant, devoid of cell-surface glycopeptidolipids (GPLs), causes more severe clinical disease than the smooth (S) variant, but the underlying mechanisms of R-variant virulence remain obscure. Exploiting the optical transparency of zebrafish embryos, we observed that the increased virulence of theM. abscessusR variant compared with the S variant correlated with the loss of GPL production. The virulence of the R variant involved the massive production of serpentine cords, absent during S-variant infection, and the cords initiated abscess formation leading to rapid larval death. Cording occurred within the vasculature and was highly pronounced in the central nervous system (CNS). It appears thatM. abscessusis transported to the CNS within macrophages. The release ofM. abscessusfrom apoptotic macrophages initiated the formation of cords that grew too large to be phagocytized by macrophages or neutrophils. This study is a description of the crucial role of cording in the in vivo physiopathology ofM. abscessusinfection and emphasizes cording as a mechanism of immune evasion.

scholarly journals Biogenesis of Tubular ER-to-Golgi Transport Intermediates

2006 ◽  
Vol 17 (2) ◽  
pp. 723-737 ◽  
Author(s):  
Jeremy C. Simpson ◽  
Tommy Nilsson ◽  
Rainer Pepperkok
Keyword(s):  
Membrane Proteins ◽  
In Vivo Imaging ◽  
Molecular Regulation ◽  
Rab Proteins ◽  
Vesicle Budding ◽  
Golgi Transport ◽  
Cytoplasmic Tails ◽  
Tubular Transport ◽  
Transport Carrier

Tubular transport intermediates (TTIs) have been described as one class of transport carriers in endoplasmic reticulum (ER)-to-Golgi transport. In contrast to vesicle budding and fusion, little is known about the molecular regulation of TTI synthesis, transport and fusion with target membranes. Here we have used in vivo imaging of various kinds of GFP-tagged proteins to start to address these questions. We demonstrate that under steady-state conditions TTIs represent ∼20% of all moving transport carriers. They increase in number and length when more transport cargo becomes available at the donor membrane, which we induced by either temperature-related transport blocks or increased expression of the respective GFP-tagged transport markers. The formation and motility of TTIs is strongly dependent on the presence of intact microtubules. Microinjection of GTPγS increases the frequency of TTI synthesis and the length of these carriers. When Rab proteins are removed from membranes by microinjection of recombinant Rab-GDI, the synthesis of TTIs is completely blocked. Microinjection of the cytoplasmic tails of the p23 and p24 membrane proteins also abolishes formation of p24-containing TTIs. Our data suggest that TTIs are ER-to-Golgi transport intermediates that form preferentially when transport-competent cargo exists in excess at the donor membrane. We propose a model where the interaction of the cytoplasmic tails of membrane proteins with microtubules are key determinants for TTI synthesis and may also serve as a so far unappreciated model for aspects of transport carrier formation.

scholarly journals Evidence for a Role of CLIP-170 in the Establishment of Metaphase Chromosome Alignment

1998 ◽  
Vol 141 (4) ◽  
pp. 849-862 ◽  
Author(s):  
Denis Dujardin ◽  
U. Irene Wacker ◽  
Anne Moreau ◽  
Trina A. Schroer ◽  
Janet E. Rickard ◽  
...  
Keyword(s):  
Metaphase Plate ◽  
Polar Regions ◽  
Static Interaction ◽  
Transport Vesicles ◽  
Vitro Binding ◽  
Chromosome Alignment ◽  
Dynactin Complex

CLIPs (cytoplasmic linker proteins) are a class of proteins believed to mediate the initial, static interaction of organelles with microtubules. CLIP-170, the CLIP best characterized to date, is required for in vitro binding of endocytic transport vesicles to microtubules. We report here that CLIP-170 transiently associates with prometaphase chromosome kinetochores and codistributes with dynein and dynactin at kinetochores, but not polar regions, during mitosis. Like dynein and dynactin, a fraction of the total CLIP-170 pool can be detected on kinetochores of unattached chromosomes but not on those that have become aligned at the metaphase plate. The COOH-terminal domain of CLIP-170, when transiently overexpressed, localizes to kinetochores and causes endogenous full-length CLIP-170 to be lost from the kinetochores, resulting in a delay in prometaphase. Overexpression of the dynactin subunit, dynamitin, strongly reduces the amount of CLIP-170 at kinetochores suggesting that CLIP-170 targeting may involve the dynein/dynactin complex. Thus, CLIP-170 may be a linker for cargo in mitosis as well as interphase. However, dynein and dynactin staining at kinetochores are unaffected by this treatment and further overexpression studies indicate that neither CLIP-170 nor dynein and dynactin are required for the formation of kinetochore fibers. Nevertheless, these results strongly suggest that CLIP-170 contributes in some way to kinetochore function in vivo.

scholarly journals Dynamics of Ankyrin-containing Complexes in Chicken Embryonic Erythroid Cells: Role of Phosphorylation

2001 ◽  
Vol 12 (12) ◽  
pp. 3864-3874 ◽  
Author(s):  
Sourav Ghosh ◽  
John V. Cox
Keyword(s):  
Complex Formation ◽  
Anion Exchanger ◽  
Erythroid Cells ◽  
Binding Studies ◽  
Phosphatase Inhibitors ◽  
In Vitro Binding ◽  
Vitro Binding

Chicken erythroid ankyrin undergoes a fairly rapid cycle of cytoskeletal association, dissociation, and turnover. In addition, the cytoskeletal association of ankyrin is regulated by phosphorylation. Treatment of erythroid cells with serine and threonine phosphatase inhibitors stimulated the hyperphosphorylation of the 225- and 205-kDa ankyrin isoforms, and dissociated the bulk of these isoforms from cytoskeletal spectrin. In vitro binding studies have shown that this dissociation of ankyrin from spectrin in vivo can be attributed to a reduced ability of hyperphosphorylated ankyrin to bind spectrin. Interestingly, a significant fraction of detergent insoluble ankyrin accumulates in a spectrin-independent pool. At least some of this spectrin-independent pool of ankyrin is complexed with the AE1 anion exchanger, and the solubility properties of this pool are also regulated by phosphorylation. Treatment of cells with serine and threonine phosphatase inhibitors had no effect on ankyrin/AE1 complex formation. However, these inhibitors were sufficient to shift ankyrin/AE1 complexes from the detergent insoluble to the soluble pool. These analyses, which are the first to document the in vivo consequences of ankyrin phosphorylation, indicate that erythroid ankyrin-containing complexes can undergo dynamic rearrangements in response to changes in phosphorylation.

scholarly journals Nucleocytoplasmic Shuttling of the Golgi Phosphatidylinositol 4-Kinase Pik1 Is Regulated by 14-3-3 Proteins and Coordinates Golgi Function with Cell Growth

2008 ◽  
Vol 19 (3) ◽  
pp. 1046-1061 ◽  
Author(s):  
Lars Demmel ◽  
Mike Beck ◽  
Christian Klose ◽  
Anne-Lore Schlaitz ◽  
Yvonne Gloor ◽  
...  
Keyword(s):  
Nutrient Supply ◽  
Nucleocytoplasmic Shuttling ◽  
Lipid Kinase ◽  
Golgi Transport ◽  
Dual Localization ◽  
Transport Vesicles ◽  
Catalytically Active ◽  
Nutrient Signaling ◽  
Phosphatidylinositol 4

The yeast phosphatidylinositol 4-kinase Pik1p is essential for proliferation, and it controls Golgi homeostasis and transport of newly synthesized proteins from this compartment. At the Golgi, phosphatidylinositol 4-phosphate recruits multiple cytosolic effectors involved in formation of post-Golgi transport vesicles. A second pool of catalytically active Pik1p localizes to the nucleus. The physiological significance and regulation of this dual localization of the lipid kinase remains unknown. Here, we show that Pik1p binds to the redundant 14-3-3 proteins Bmh1p and Bmh2p. We provide evidence that nucleocytoplasmic shuttling of Pik1p involves phosphorylation and that 14-3-3 proteins bind Pik1p in the cytoplasm. Nutrient deprivation results in relocation of Pik1p from the Golgi to the nucleus and increases the amount of Pik1p–14-3-3 complex, a process reversed upon restored nutrient supply. These data suggest a role of Pik1p nucleocytoplasmic shuttling in coordination of biosynthetic transport from the Golgi with nutrient signaling.

scholarly journals Truncation of ADAMTS13 by Plasmin Enhances Its Activity in Plasma

2018 ◽  
Vol 118 (03) ◽  
pp. 471-479 ◽  
Author(s):  
Chantal Clark ◽  
Mirjam Mebius ◽  
Steven de Maat ◽  
Aloysius Tielens ◽  
Philip de Groot ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Binding Studies ◽  
Direct Binding ◽  
Self Association ◽  
A Disintegrin And Metalloproteinase ◽  
Static Conditions ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) cleaves von Willebrand Factor (VWF) multimers to control their thrombogenicity. The fibrinolytic enzyme plasmin can cleave VWF in a similar manner. However, plasmin can also cleave ADAMTS13, which ultimately inactivates it. This leaves the overall role of plasmin in primary haemostasis uncertain.We investigated the combined molecular effects of plasmin on VWF and ADAMTS13. We first identified that plasmin destroys FRETS-VWF73 substrate by cleaving the ADAMTS13 binding region in a buffered system. We next investigated how plasmin affects both VWF and ADAMTS13 under static conditions in plasma by western blotting. We found that globular VWF is largely protected from plasmin cleavage. However, ADAMTS13 is rapidly cleaved under these conditions, suggesting inactivation. Surprisingly, we observed that plasmin enhances ADAMTS13 activity in a modified two-stage FRETS-VWF73 assay that protects FRETS-VWF73 substrate from degradation. In direct binding studies under the same conditions, we found that plasmin generates multiple C-terminally truncated forms of ADAMTS13 with VWF-binding capacity. In an effort to seek evidence for this mechanism in vivo, we analysed plasma from patients with systemic amyloidosis, which is hallmarked by a hyperfibrinolytic state. We found that their plasma contained increased levels of C-terminally truncated forms of ADAMTS13, which correlated with their hyperfibrinolytic state.We propose that truncation of ADAMTS13 by plasmin abolishes intramolecular self-association, which improves interaction with unfolded VWF.

scholarly journals REFRACTORY FUNGAL VAGINITIS TREATED BY TOPICAL AMPHOTERICIN B. Review

2020 ◽  
Vol 16 (2) ◽  
pp. 55-58
Author(s):  
Falah Hasan Obayes AL-Khikani
Keyword(s):  
Antifungal Activity ◽  
Side Effects ◽  
Amphotericin B ◽  
Intravenous Injection ◽  
Fungal Infections ◽  
Wide Spectrum ◽  
Candida Spp

Vaginitis is a common problem for women regarding a worldwide health challenge with many side effects. Vaginitis is among the most visiting to gynecology clinics. About 75% of all reproductive women had at least one fungal vaginitis infection in their life, and more than 40% will have two or more than two.  Candida spp is the most prevalent in fungal vaginitis, while reports for unusual fungi were observed as mucor spp. Amphotericin B (AmB) belongs to the polyene group has a wide spectrum in vitro and in vivo antifungal activity. All of the known available formulas of AmB are administrated via intravenous injection to treat severe systemic fungal infections, while the development of the topical formula of AmB is still under preliminary development including topical vaginal AmB. Due to the revealing of antimicrobial-resistant fungi in recent years, this study explains the role of topical AmB in treating refractory fungi vaginitis that may not a response to other drugs reported in many cases that may help researchers to develop new effective formula of AmB regarding fungal vaginitis.

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