Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GOLGI APPARATUS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed1990

Retinoid modulation of cell-free membrane transfer between endoplasmic reticulum and Golgi apparatus.

Cell-free transfer of radiolabeled membrane proteins from part-rough, part-smooth transitional elements of the endoplasmic reticulum to Golgi apparatus immobilized to nitrocellulose in the presence of nucleoside triphosphate, an ATP-regenerating system and a cytosol fraction was promoted by retinol. At an optimum concentration of 1 microgram/ml, the rate and amount of transfer was approximately doubled over 1 to 2 h of incubation in the cell-free system. The transition vesicles induced to form in the cell-free system were concentrated by preparative free-flow electrophoresis in order to study separately the steps of vesicle formation from transitional endoplasmic reticulum and the steps of vesicle fusion with Golgi apparatus. The retinol effect was on vesicle formation as evidenced by an approx. 2-fold increase in transition vesicle numbers, as determined by electron microscope morphometry, and amount from protein determinations on the isolated fractions enriched in transition vesicles. The retinol response in the complete transfer could be eliminated by addition of concentrated cytosol, including cytosol depleted of retinol. An interaction of retinol with some component of the vesicle formation process, possibly involving guanine nucleotides, is indicated.

Adenosine Triphosphate↗
PubMed1995

Three-dimensional organization of stable microtubules and the Golgi apparatus in the somata of developing chick sensory neurons.

Microtubules play a role important in regulating cell shape and in mediating organelle movements. These functions are especially important in elaborately branched neurons, which have many stable microtubules that are resistant to cold and to microtubule depolymerizing drugs. We examined the three-dimensional organization of microtubules in cell bodies of cultured chick embryo sensory neurons, using confocal laser scanning microscopy. Microtubules were visualized with antibodies against alpha-tubulin and post-translationally modified forms of alpha-tubulin that accumulate in older microtubules. Optical sections were collected through neuronal somata, and the images were reconstructed in three dimensions. In neuronal perikarya a dense network of older microtubules is co-localized with the Golgi apparatus. This complex of the Golgi and older microtubules usually lies beneath the cell nucleus and is oriented toward the substratum. From this region, older microtubules extend into each neurite. A cage of older microtubules extends around the nucleus to the top of the perikaryon. The stability of these microtubules was confirmed by their resistance to the depolymerizing drug, nocodazole. This arrangement of stable microtubules in a developing neuron provides a supporting cytoskeleton and a transport pathway for movement of cytoplasmic components between the Golgi apparatus, the perikaryon and developing neurites.

Animals↗
PubMed1997

Human Rer1 is localized to the Golgi apparatus and complements the deletion of the homologous Rer1 protein of Saccharomyces cerevisiae.

Sec12p is a type II membrane glycoprotein in the endoplasmic reticulum (ER) of Saccharomyces cerevisiae which is essential for transport vesicle budding. It is the guanine nucleotide exchange factor for the small GTP-binding protein Sar1p which is a constituent of COP II ER to Golgi vesicles. We report the sequence and localization of the human homologue to yeast Rer1p, which has recently been identified genetically as an essential component for retention of Sec12p in the ER. Reverse polymerase chain reaction was used to obtain cDNAs from HeLa cells. They code for a protein of 196 amino acids, corresponding to a molecular mass of 23 kDa. The translated sequence is 44% identical and 65% similar to yeast Rer1 protein. The four putative transmembrane domains are predicted to form a W-topology with both N- and C-terminus facing the cytosol. The functional activity of myc-tagged human Rer1 was demonstrated by the complementation of the RER1 deletion in S. cerevisiae. Mislocalization of the Sec12-reporter protein was reduced similar to the results obtained with yeast Rer1p. Human Rer1 protein was expressed in HeLa cells and the subcellular distribution analyzed by double immunofluorescence and immunoelectron microscopy of thawed cryosections. The tagged protein was localized to the Golgi apparatus and peripheral elements of the ER-Golgi interface. High overexpression leads to relocation of human Rer1 to ER-like structures together with KDEL-receptor and affects the structural organization of the Golgi apparatus. Under conditions of brefeldin A treatment, human Rer1 distributes together with recycling Golgi proteins.

Adaptor Proteins, Vesicular Transport↗
PubMed2002

Phospholipase D2 is localized to the rims of the Golgi apparatus in mammalian cells.

Phospholipase D (PLD) hydrolyzes phosphatidylcholine to generate phosphatidic acid, a molecule known to have multiple physiological roles, including release of nascent secretory vesicles from the trans-Golgi network. In mammalian cells two forms of the enzyme, PLD1 and PLD2, have been described. We recently demonstrated that PLD1 is localized to the Golgi apparatus, nuclei, and to a lesser extent, plasma membrane. Due to its low abundance, the intracellular localization of PLD2 has been characterized only indirectly through overexpression of chimeric proteins. Using antibodies specific to PLD2, together with immunofluorescence microscopy, herein we demonstrate that a significant fraction of endogenous PLD2 localized to the perinuclear Golgi region and was also distributed throughout cells in dense cytoplasmic puncta; a fraction of which colocalized with caveolin-1 and the plasma membrane. On treatment with brefeldin A, PLD2 translocated into the nucleus in a manner similar to PLD1, suggesting a potential role in nuclear signaling. Most significantly, cryoimmunogold electron microscopy demonstrated that in pituitary GH(3) cells >90% of PLD2 present in the Golgi apparatus was localized to cisternal rims and peri-Golgi vesicles exclusively. The data are consistent with a model whereby PLD2 plays a role in Golgi vesicular transport.

Animals↗
PubMed1988

Human proteins IEF 58 and 57a are associated with the Golgi apparatus.

A mouse monoclonal antibody (mAB 22-II-D8B) raised against lysed transformed human amnion cells (AMA) has been characterized. The mAB decorated the Golgi apparatus in growing and quiescent cultured monolayer cells (fibroblasts and epithelial cells) of various species as determined by double immunofluorescence labeling and colocalization with galactosyltransferase antibodies. It reacted with the acidic human proteins IEF 58 (Mr = 29,000) and 57a, respectively (Mr = 30,000) (HeLa protein catalogue number; [(1982) Clin. Chem. 28, 766]), Golgi staining was also observed in BS-C-1 cells microinjected with mAB 22-II-D8B suggesting that the epitopes recognized by the antibody are most likely located on the cytoplasmic face of the membranes. The precise localization of the antigens to the various cisternae of the Golgi apparatus could not be demonstrated by immunogold cytochemistry on ultrathin cryosections due to either weak reactivity of the antibody or low concentration of the antigens. Immunofluorescence staining with mAB 22-II-D8B of lymphoid human Molt-4 cells and some human tissues failed to reveal any significant staining even though these expressed high levels of both IEF 58 and 57a. These results are taken to imply that the epitopes recognized by mAB 22-II-D8B may be masked in some cell types.

Animals↗
PubMed2001

Fragmentation and re-assembly of the Golgi apparatus in vitro. A requirement for phosphatidic acid and phosphatidylinositol 4,5-bisphosphate synthesis.

Recent work from our laboratory demonstrated that phosphatidic acid (PA) and phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)), are required to maintain the structural integrity of the Golgi apparatus. To investigate the role of these lipids in regulating Golgi structure and function, we developed a novel assay to follow the release of post-Golgi vesicles. Isolated rat liver Golgi membranes were incubated with [(3)H]CMP sialic acid to radiolabel endogenous soluble and membrane glycoproteins present in the late Golgi and trans-Golgi network. The release of post-Golgi secretory vesicles was determined by measuring incorporation of (3)H-labeled proteins into a medium speed supernatant. Vesicle budding was dependent on temperature, cytosol, energy and time. Electron microscopy of Golgi fractions prior to and after incubation demonstrated that the stacked Golgi cisternae generated a heterogeneous population of vesicles (50- to 350-nm diameter). Inhibition of phospholipase D-mediated PA synthesis, by incubation with 1-butanol, resulted in the complete fragmentation of the Golgi membranes in vitro into 50- to 100-nm vesicles; this correlated with diminished PtdIns(4,5)P(2) synthesis. Following alcohol washout, PA synthesis resumed and in the presence of cytosol PtdIns(4,5)P(2) synthesis was restored. Most significantly, under these conditions the fragmented Golgi elements reformed into flattened cisternae and the re-assembled Golgi supported vesicle release. These data demonstrate that inositol phospholipid synthesis is essential for the structure and function of the Golgi apparatus.

Alcohols↗
PubMed1989

Involvement of the Golgi apparatus in sorting of materials to opposite ends of frog rod retinal photoreceptors.

We have studied the rod cells of retinas of Rana pipiens by phosphatase cytochemistry and immunocytochemistry. We find that the Golgi apparatus of these cells, although different in its intracellular distribution from that of other neurons, has a cis-trans organization like that of other neurons as regards morphological features and the distribution of phosphatase activities. Antibodies against opsin bind to several sacs of the rod Golgi apparatus, especially those at the trans side of the Golgi stack. This suggests that Golgi involvement in the packaging of opsin for eventual delivery to the photoreceptive outer segments of the cell involves passage through trans Golgi systems. Proteins destined for the opposite end of the cell--the presynaptic terminal--also seem to pass through trans Golgi systems, as is indicated both by immunocytochemical localization of the synaptic vesicle protein p38 (synaptophysin) and by the presence of thiamine pyrophosphatase activity in some of the synaptic vesicles. Our findings suggest that sorting of membrane proteins destined for opposite ends of the photoreceptor takes place in systems at or near the trans Golgi face.

Animals↗
PubMed1981

A three-dimensional study of organelle interrelationships in regenerating rat liver. 6. Golgi apparatus.

Luminal materials from the ER are supplied to the Golgi apparatus (GA) either via precisternal elements (PE) detaching from the ER and building up a first cisterna, or via direct luminal continuities with the sER. Membrane supply is believed to follow only the first of these two pathways. It is further argued that during the processing of luminal materials and membrane - two Golgi activities that proceed at a different rate - bits of membrane carrying the differentiation enzymes are recycled to less differentiated membranes in the form of Golgi vesicles (GV).

Animals↗
PubMed1991

Oligomerization and intracellular protein transport: dimerization of intestinal dipeptidylpeptidase IV occurs in the Golgi apparatus.

It was postulated that newly synthesized membrane proteins need to be assembled into oligomers in the endoplasmic reticulum in order to be transported to the Golgi apparatus. By use of the differentiated human adenocarcinoma cell line Caco-2, the general validity of this proposal was studied for small intestinal brush border enzymes which are dimers in most mammalian species. Chemical cross-linking experiments and sucrose gradient rate-zonal centrifugation revealed that dipeptidylpeptidase IV is present as a dimer in the brush border membrane of Caco-2 cells whereas the disaccharidase sucrase-isomaltase appears to be a monomer. Dipeptidylpeptidase IV was found to dimerize immediately after complex glycosylation, an event associated with the Golgi apparatus. Dimerization of this enzyme was inhibited by CCCP but did not depend on complex glycosylation of N-linked carbohydrates as assessed by the use of the trimming inhibitor 1-deoxymannojirimycin. It is concluded that dimerization of dipeptidylpeptidase IV occurs in a late Golgi compartment and therefore cannot be a prerequisite for its export from the endoplasmic reticulum.

Adenocarcinoma↗
PubMed1984

Effect of monensin on the Golgi apparatus of absorptive cells in the small intestine of the rat. Morphological and cytochemical studies.

The effect of short-time treatment with the ionophore monensin, administered intraluminally at concentrations of 5 and 10 microM, was studied on the Golgi apparatus of absorptive cells in the small intestine of the rat. At 2-3 min after treatment most of the Golgi stacks exhibited dilated cisternae. At 4-5 min stacked cisternae were absent; they were replaced by groups of smooth-surfaced vacuoles. Dilatation and vacuolization occurred in the entire stacks without preferential effect on any particular Golgi subcompartment. Monensin did not influence the cytochemical Golgi reaction of thiamine pyrophosphatase and acid phosphatase. The characteristic staining pattern of these two enzymes in all Golgi cisternae of absorptive cells in the proximal small intestine, and the reactivity restricted to trans cisternae in distal segments of the small intestine, were unchanged after treatment with monensin. In the distal small intestine, the cytochemical pattern allowed the monensin-induced vacuoles to be attributed to the former cis- or trans-Golgi face. Further, the cytochemical results demonstrate that vacuolization is not restricted to the stacked cisternae, but includes the trans-most cisterna. The latter, usually located at some distance from the Golgi stacks, has been defined as belonging to the GERL system in several types of cells. The clear response to monensin, an agent that selectively affects the Golgi apparatus, indicates common properties between trans-most and stacked Golgi cisternae.

Acid Phosphatase↗
PubMed1976

The topographical location and unique nature of a glucokinase associated with the Golgi apparatus of rat liver.

A particulate glucokinase was recovered in the Golgi-rich fraction of rat liver prepared by the method of Morré [Methods Enzymol. (1971) 22, 130-148], thus extending the demonstration by Berthillier et al. [Biochim. Biophys. Acta (1973), 293, 370-378] of particulate glucokinase activity in a microsomal subfraction that showed enrichment in Golgi characteristics. The purity of this fraction was examined and it was then subjected to several treatments, the action of Triton X-100, freezing and thawing, and sonication to establish the topographical location of the glucokinase activity thus solubilized. The evidence suggests that the glucokinase activity is either soluble in the lumen of the Golgi apparatus or loosely associated with the inside of the Golgi membranes.

Animals↗
PubMed1988

Contribution of the Golgi apparatus components to the formation of the acrosomic system and chromatoid body in rat spermatids.

The cytochemical distribution of two different acid phosphatases, nicotinamide adenine dinucleotide phosphatase (NADPase) and cytidine monophosphatase (CMPase), was analyzed within the Golgi apparatus, acrosomic system, and chromatoid body of early spermatids. Within the saccules composing the Golgi cortex, the phosphatases were localized in specific and nonoverlapping compartments: the cis-tubular network, or cis-element, and the first underlying saccule were unreactive for both enzymes, the following four to five saccules were reactive for NADPase, and the last three saccules were reactive for CMPase. Vesicles of various sizes and short membranous tubules, present near the edges of saccules and in the medulla of the Golgi apparatus, were NADPase- and/or CMPase-positive. The acrosomic system showed a weak but significant NADPase reactivity and a strong CMPase reactivity. The vesicles associated with the chromatoid body were reactive for NADPase and/or CMPase. The combined observations indicate that the two cytochemically distinct compartments of the Golgi cortex, the NADPase- and CMPase-positive saccules, independently contribute to the formation of the acrosomic system and the vesicular component of the chromatoid body.

Acrosome↗
PubMed1998

Leptin receptor immunoreactivity is associated with the Golgi apparatus of hypothalamic neurons and glial cells.

Leptin has emerged as a major peripheral hormone, controlling central mechanisms of metabolism and related autonomic and endocrine functions. In the regulation of hypothalamic neurones, leptin is suggested to affect different second messenger systems and transcription regulating factors. The present study reports the predominant localization of leptin receptor immunoreactivity in the cis and trans cisternae of the Golgi apparatus in hypothalamic neuronal and glial cells. In these hypothalamic cells, translocation of leptin receptor immunoreactivity from the Golgi apparatus to the perikaryal membrane, nucleus or to the cytoplasm was not apparent after manipulation of the metabolic state either by fasting or suppression of the thyroid axis. On the other hand, leptin receptor immunoreactivity was associated with the perikaryal membrane of neurones in other parts of the central nervous system, including the dentate gyrus and the cingulate cortex. These data indicate an extremely high turnover of leptin receptors in hypothalamic target sites, but also raise the possibility that leptin may interact with the Golgi apparatus-related mechanisms to alter intracellular mechanisms.

Animals↗
PubMed1999

The N-terminal 77 amino acids from tobacco N-acetylglucosaminyltransferase I are sufficient to retain a reporter protein in the Golgi apparatus of Nicotiana benthamiana cells.

In order to investigate sequences of tobacco N-acetylglucosaminyltransferase I (GnTI), involved in targeting to and retention in the plant Golgi apparatus the cytoplasmic transmembrane stem (CTS) region of the enzyme was cloned in frame with the cDNA of the green fluorescent protein (gfp) and subsequently transiently expressed in Nicotiana benthamiana plants using a tobacco mosaic virus (TMV) based expression vector. Confocal laser scanning microscopy showed small fluorescent vesicular bodies in CTS-gfp expressing cells, while gfp alone expressed in control plants was uniformly distributed in the cytoplasm. The CTS-gfp fusion protein colocalised with immunolabelling observed by an antibody specific for the Golgi located plant Lewis a epitope. Furthermore, treatment with brefeldin A, a Golgi specific drug, resulted in the formation of large fluorescent vesiculated areas. These results strongly suggest a Golgi location for CTS-gfp and as a consequence our findings reveal that the N-terminal 77 amino acids of tobacco GnTI are sufficient to target to and to retain a reporter protein in the plant Golgi apparatus and that TMV based vectors are suitable vehicles for rapid delivery of recombinant proteins to the secretory pathway.

Biological Transport↗
PubMed1986

The trans-tubular network of the hepatocyte Golgi apparatus is part of the secretory pathway.

We have recently demonstrated the presence of sialyltransferase and sialic acid in a trans-tubular network (TTN) continuous with trans Golgi apparatus cisternae of rat liver hepatocytes. Based on these findings, we concluded that this structure, which also exhibited thiamine pyrophosphatase and acid phosphatase activity, is an integral part of the Golgi apparatus and functions in sialylation. In the present study, by comparing the distribution of a major hepatocyte secretory product with that of sialyltransferase, we sought to determine whether the TTN is also part of the secretory pathway. Examination of adjacent serial thin sections labeled for albumin showed its presence throughout the TTN and simultaneously provided new details about the structural complexity of the TTN. Double-immunolabeling with protein A-gold allowed the direct demonstration of albumin throughout the sialyltransferase containing TTN. Additional double staining protocols (combination of preembedding enzyme cytochemistry with postembedding immunolabeling) revealed the presence of albumin in both the thiamine pyrophosphatase and acid phosphatase positive regions of the TTN. These data show that albumin, a nonglycosylated secretory protein, reaches the TTN where terminal glycosylation of glycoproteins occurs. Therefore, it appears that the TTN of rat hepatocytes which functions in terminal glycosylation is also part of the constitutive secretory pathway.

Albumins↗
PubMed2001

Vacuolar storage proteins are sorted in the cis-cisternae of the pea cotyledon Golgi apparatus.

Developing pea cotyledons contain functionally different vacuoles, a protein storage vacuole and a lytic vacuole. Lumenal as well as membrane proteins of the protein storage vacuole exit the Golgi apparatus in dense vesicles rather than in clathrin-coated vesicles (CCVs). Although the sorting receptor for vacuolar hydrolases BP-80 is present in CCVs, it is not detectable in dense vesicles. To localize these different vacuolar sorting events in the Golgi, we have compared the distribution of vacuolar storage proteins and of alpha-TIP, a membrane protein of the protein storage vacuole, with the distribution of the vacuolar sorting receptor BP-80 across the Golgi stack. Analysis of immunogold labeling from cryosections and from high pressure frozen samples has revealed a steep gradient in the distribution of the storage proteins within the Golgi stack. Intense labeling for storage proteins was registered for the cis-cisternae, contrasting with very low labeling for these antigens in the trans-cisternae. The distribution of BP-80 was the reverse, showing a peak in the trans-Golgi network with very low labeling of the cis-cisternae. These results indicate a spatial separation of different vacuolar sorting events in the Golgi apparatus of developing pea cotyledons.

COP-Coated Vesicles↗
PubMed1989

H+-translocating ATPase in Golgi apparatus. Characterization as vacuolar H+-ATPase and its subunit structures.

Golgi apparatus was prepared from rat liver, and enzymatic properties and the subunit structure of the H+-ATPase were characterized. GTP (and also ITP) was found to drive H+-transport with about 20% of the initial velocity as that of ATP. Bafilomycin, a specific inhibitor for vacuolar H+-ATPase, inhibited the activity at 2.5 nM. The H+-ATPase was completely inhibited in the cold in the presence of MgATP (5 mM) and NaNO3 (0.1 M). The cold inactivation of the H+-ATPase resulted in release of a set of polypeptides from Golgi membrane, with molecular masses almost identical to that of the hydrophilic sector of chromaffin granule H+-ATPase (72, 57, 41, 34, and 33 kDa). Three of these polypeptides (72, 57, and 34 kDa), cross-reacted with antibodies against the corresponding subunits of the chromaffin granule H+-ATPase. A counterpart of the 39-kDa hydrophobic component of chromaffin granule H+-ATPase was identified in the membrane, but no 115-kDa component was found. Hence, the Golgi H+-ATPase shows typical features of vacuolar H+-ATPase, in relatively low substrate specificity, its response to inhibitors, inactivation by cold treatment in the presence of MgATP, and subunit composition judged by antibody cross-reactivity.

Adenosine Diphosphate↗