Role of an N-ethylmaleimide-sensitive transport component in promoting fusion of transport vesicles with cisternae of the Golgi stack

Cell ◽  
1988 ◽  
Vol 54 (2) ◽  
pp. 221-227 ◽  
Author(s):  
V MALHOTRA
2021 ◽  
Author(s):  
Lawrence G Welch ◽  
Sew-Yeu Peak-Chew ◽  
Farida Begum ◽  
Tim J Stevens ◽  
Sean Munro

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.


1996 ◽  
Vol 109 (7) ◽  
pp. 1975-1989 ◽  
Author(s):  
T. Nilsson ◽  
C. Rabouille ◽  
N. Hui ◽  
R. Watson ◽  
G. Warren

Using a series of chimeric and truncated N-acetylglucosaminyltransferase I (NAGT I) molecules we have shown that part of the lumenal stalk region is both necessary and sufficient for kin recognition of mannosidase II and retention in the Golgi stack. The membrane-spanning domain was not required for retention, but replacing part or all of this domain with leucine residues did have a dramatic effect on Golgi morphology. In stable cell lines, stacked cisternae were replaced by tubulo-vesicular clusters containing the mutated NAGT I. The loss of stacked cisternae was proportional to the number of leucines used to replace the membrane-spanning domain.


1999 ◽  
Vol 147 (7) ◽  
pp. 1457-1472 ◽  
Author(s):  
Chung-Chih Lin ◽  
Harold D. Love ◽  
Jennifer N. Gushue ◽  
John J.M. Bergeron ◽  
Joachim Ostermann

Secretory proteins exit the ER in transport vesicles that fuse to form vesicular tubular clusters (VTCs) which move along microtubule tracks to the Golgi apparatus. Using the well-characterized in vitro approach to study the properties of Golgi membranes, we determined whether the Golgi enzyme NAGT I is transported to ER/Golgi intermediates. Secretory cargo was arrested at distinct steps of the secretory pathway of a glycosylation mutant cell line, and in vitro complementation of the glycosylation defect was determined. Complementation yield increased after ER exit of secretory cargo and was optimal when transport was blocked at an ER/Golgi intermediate step. The rapid drop of the complementation yield as secretory cargo progresses into the stack suggests that Golgi enzymes are preferentially targeted to ER/Golgi intermediates and not to membranes of the Golgi stack. Two mechanisms for in vitro complementation could be distinguished due to their different sensitivities to brefeldin A (BFA). Transport occurred either by direct fusion of preexisting transport intermediates with ER/Golgi intermediates, or it occurred as a BFA-sensitive and most likely COP I–mediated step. Direct fusion of ER/Golgi intermediates with cisternal membranes of the Golgi stack was not observed under these conditions.


2000 ◽  
Vol 150 (6) ◽  
pp. 1263-1270 ◽  
Author(s):  
Lelio Orci ◽  
Mylène Amherdt ◽  
Mariella Ravazzola ◽  
Alain Perrelet ◽  
James E. Rothman

A central feature of cisternal progression/maturation models for anterograde transport across the Golgi stack is the requirement that the entire population of steady-state residents of this organelle be continuously transported backward to earlier cisternae to avoid loss of these residents as the membrane of the oldest (trans-most) cisterna departs the stack. For this to occur, resident proteins must be packaged into retrograde-directed transport vesicles, and to occur at the rate of anterograde transport, resident proteins must be present in vesicles at a higher concentration than in cisternal membranes. We have tested this prediction by localizing two steady-state residents of medial Golgi cisternae (mannosidase II and N-acetylglucosaminyl transferase I) at the electron microscopic level in intact cells. In both cases, these abundant cisternal constituents were strongly excluded from buds and vesicles. This result suggests that cisternal progression takes place substantially more slowly than most protein transport and therefore is unlikely to be the predominant mechanism of anterograde movement.


2005 ◽  
Vol 16 (7) ◽  
pp. 3211-3222 ◽  
Author(s):  
Christine Sütterlin ◽  
Roman Polishchuk ◽  
Matt Pecot ◽  
Vivek Malhotra

At the onset of mitosis, the pericentriolar Golgi apparatus of mammalian cells is converted into small fragments, which are dispersed throughout the cytosol. The Golgi-associated protein GRASP65 is involved in this process. To address the role of GRASP65 in mitotic Golgi fragmentation, we depleted the protein from HeLa cells by RNAi. In the absence of GRASP65, the number of cisternae per Golgi stack is reduced without affecting the overall organization of Golgi membranes and protein transport. GRASP65-depleted cells entered mitosis, but accumulated in metaphase with condensed chromatin and multiple aberrant spindles and eventually died. Although Centrin2 and g-tubulin were detected in two of the spindle poles, the other spindle poles contained g-tubulin, but not Centrin2. Furthermore, we provide evidence that the expression of the C-terminus of GRASP65 interferes with entry of cells into mitosis. Our results suggest the requirement for GRASP65 in the regulation of spindle dynamics rather than a direct role in the stacking of Golgi cisternae. This novel function is in addition to the previously established negative role of GRASP65 at the G2/M transition, which is mediated by its C-terminus.


1984 ◽  
Vol 99 (1) ◽  
pp. 260-271 ◽  
Author(s):  
J E Rothman ◽  
R L Miller ◽  
L J Urbani

The transfer of the vesicular stomatitis virus-encoded glycoprotein (G protein) between Golgi populations in fused cells (Rothman, J. E., L. J. Urbani, and R. Brands. 1984. J. Cell Biol. 99:248-259) is exploited here to study and to help define the compartmental organization of the Golgi stack and to characterize the mechanism of intercompartmental transport. We find that G protein that has just received its peripheral N-acetylglucosamine in the Golgi complex of one cell is efficiently transferred to the Golgi complex of another cell to receive galactose (Gal). Remarkably, this transport occurs at the same rate between these two compartments whether they are present in the same or different Golgi populations. Therefore, a dissociative (presumably vesicular) transport step moves G protein from one part of the Golgi in which N-acetylglucosamine is added to another in which Gal is added. Minutes later, upon receiving Gal, the same G protein molecules are very poorly transferred to an exogenous Golgi population after cell fusion. Therefore, once this intercompartmental transfer has already taken place (before fusion), it cannot take place again (after fusion); i.e., transport across the compartment boundary in the Golgi complex that separates the sites of N-acetylglucosamine and Gal incorporation is a vectorial process. We conclude that transfers between Golgi cisternae occur by a stochastic process in which transport vesicles budding from cisternae dissociate, can diffuse away, and then attach to and fuse with the appropriate target cisterna residing in the same or in a different stack, based on a biochemical pairing after a random encounter. Under these circumstances, a transported protein would almost always randomize among stacks with each intercisternal transfer; it would not progress systematically through a single stack. Altogether, our studies define three sequential compartments in the Golgi stack.


1998 ◽  
Vol 140 (3) ◽  
pp. 541-551 ◽  
Author(s):  
Harold D. Love ◽  
Chung-Chih Lin ◽  
Craig S. Short ◽  
Joachim Ostermann

Secretory proteins enter the Golgi apparatus when transport vesicles fuse with the cis-side and exit in transport vesicles budding from the trans-side. Resident Golgi enzymes that have been transported in the cis-to-trans direction with the secretory flow must be recycled constantly by retrograde transport in the opposite direction. In this study, we describe the functional characterization of Golgi-derived transport vesicles that were isolated from tissue culture cells. We found that under the steady-state conditions of a living cell, a fraction of resident Golgi enzymes was found in vesicles that could be separated from cisternal membranes. These vesicles appeared to be depleted of secretory cargo. They were capable of binding to and fusion with isolated Golgi membranes, and after fusion their enzymatic contents most efficiently processed cargo that had just entered the Golgi apparatus. Those results indicate a possible role for these structures in recycling of Golgi enzymes in the Golgi stack.


1998 ◽  
Vol 141 (4) ◽  
pp. 849-862 ◽  
Author(s):  
Denis Dujardin ◽  
U. Irene Wacker ◽  
Anne Moreau ◽  
Trina A. Schroer ◽  
Janet E. Rickard ◽  
...  

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.


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