-
Current Opinion in Cell Biology Aug 2014Recent work supports the idea that cisternae of the Golgi apparatus can be assigned to three classes, which correspond to discrete stages of cisternal maturation. Each... (Review)
Review
Recent work supports the idea that cisternae of the Golgi apparatus can be assigned to three classes, which correspond to discrete stages of cisternal maturation. Each stage has a unique pattern of membrane traffic. At the first stage, cisternae form in association with the ER at multifunctional membrane assembly stations. At the second stage, cisternae synthesize carbohydrates while exchanging material via COPI vesicles. At the third stage, cisternae of the trans-Golgi network segregate into domains and produce transport carriers with the aid of specific lipids and the actin cytoskeleton. These processes are coordinated by cascades of Rab and Arf/Arl GTPases.
Topics: Animals; Biological Transport; Carbohydrates; GTP Phosphohydrolases; Golgi Apparatus; Humans
PubMed: 24840895
DOI: 10.1016/j.ceb.2014.04.010 -
Traffic (Copenhagen, Denmark) Jul 2012The conserved oligomeric Golgi (COG) complex co-ordinates retrograde vesicle transport within the Golgi. These vesicles maintain the distribution of glycosylation... (Review)
Review
The conserved oligomeric Golgi (COG) complex co-ordinates retrograde vesicle transport within the Golgi. These vesicles maintain the distribution of glycosylation enzymes between the Golgi's cisternae, and therefore COG is intimately involved in glycosylation homeostasis. Recent years have greatly enhanced our knowledge of COG's composition, protein interactions, cellular function and most recently also its structure. The emergence of COG-dependent human glycosylation disorders gives particular relevance to these advances. The structural data have firmly placed COG in the family of multi-subunit tethering complexes that it shares with the exocyst, Dsl1 and Golgi-associated retrograde protein (GARP) complexes. Here, we review our knowledge of COG's involvement in vesicle tethering at the Golgi. In particular, we consider what this knowledge may add to our molecular understanding of vesicle tethering and how it impacts on the fine tuning of Golgi function, most notably glycosylation.
Topics: Animals; Congenital Disorders of Glycosylation; Glycosylation; Golgi Apparatus; Humans; Protein Processing, Post-Translational; Transport Vesicles; Vesicular Transport Proteins
PubMed: 22300173
DOI: 10.1111/j.1600-0854.2012.01338.x -
The Journal of Cell Biology Jun 2022The mammalian Golgi comprises tightly adjacent and flattened membrane sacs called cisternae. We still do not understand the molecular organization of the Golgi and...
The mammalian Golgi comprises tightly adjacent and flattened membrane sacs called cisternae. We still do not understand the molecular organization of the Golgi and intra-Golgi transport of cargos. One of the most significant challenges to studying the Golgi is resolving Golgi proteins at the cisternal level under light microscopy. We have developed a side-averaging approach to visualize the cisternal organization and intra-Golgi transport in nocodazole-induced Golgi ministacks. Side-view images of ministacks acquired from Airyscan microscopy are transformed and aligned before intensity normalization and averaging. From side-average images of >30 Golgi proteins, we uncovered the organization of the pre-Golgi, cis, medial, trans, and trans-Golgi network membrane with an unprecedented spatial resolution. We observed the progressive transition of a synchronized cargo wave from the cis to the trans-side of the Golgi. Our data support our previous finding, in which constitutive cargos exit at the trans-Golgi while the secretory targeting to the trans-Golgi network is signal dependent.
Topics: Animals; Biological Transport; Golgi Apparatus; Mammals; Nocodazole; trans-Golgi Network
PubMed: 35467701
DOI: 10.1083/jcb.202109114 -
Traffic (Copenhagen, Denmark) Apr 2012The Golgi apparatus is an organelle that has been extensively studied in the model eukaryote, yeast. Its morphology varies among yeast species; the Golgi exists as a... (Review)
Review
The Golgi apparatus is an organelle that has been extensively studied in the model eukaryote, yeast. Its morphology varies among yeast species; the Golgi exists as a system of dispersed cisternae in the case of the budding yeast Saccharomyces cerevisiae, whereas the Golgi cisternae in Pichia pastoris and Schizosaccharomyces pombe are organized into stacks. In spite of the different organization, the mechanism of trafficking through the Golgi apparatus is believed to be similar, involving cisternal maturation, in which the resident Golgi proteins are transported backwards while secretory cargo proteins can stay in the cisternae. Questions remain regarding the organization of the yeast Golgi, the regulatory mechanisms that underlie cisternal maturation of the Golgi and transport machinery of cargo proteins through this organelle. Studies using different yeast species have provided hints to these mechanisms.
Topics: Biological Transport; Golgi Apparatus; Models, Biological; Saccharomyces cerevisiae; Signal Transduction
PubMed: 22132734
DOI: 10.1111/j.1600-0854.2011.01316.x -
Cold Spring Harbor Perspectives in... Jul 2011Since its first visualization in 1898, the Golgi has been a topic of intense morphological research. A typical mammalian Golgi consists of a pile of stapled cisternae,... (Review)
Review
Since its first visualization in 1898, the Golgi has been a topic of intense morphological research. A typical mammalian Golgi consists of a pile of stapled cisternae, the Golgi stack, which is a key station for modification of newly synthesized proteins and lipids. Distinct stacks are interconnected by tubules to form the Golgi ribbon. At the entrance site of the Golgi, the cis-Golgi, vesicular tubular clusters (VTCs) form the intermediate between the endoplasmic reticulum and the Golgi stack. At the exit site of the Golgi, the trans-Golgi, the trans-Golgi network (TGN) is the major site of sorting proteins to distinct cellular locations. Golgi functioning can only be understood in light of its complex architecture, as was revealed by a range of distinct electron microscopy (EM) approaches. In this article, a general concept of mammalian Golgi architecture, including VTCs and the TGN, is described.
Topics: Animals; COP-Coated Vesicles; Endoplasmic Reticulum; Golgi Apparatus; Humans; Mammals; Mice; Microscopy, Electron; trans-Golgi Network
PubMed: 21502307
DOI: 10.1101/cshperspect.a005181 -
Andrology Sep 2019The Hermes body (HB) previously called the cytoplasmic droplet is a focal distension of the flagellar cytoplasm of epididymal spermatozoa consisting mainly of isolated... (Review)
Review
BACKGROUND
The Hermes body (HB) previously called the cytoplasmic droplet is a focal distension of the flagellar cytoplasm of epididymal spermatozoa consisting mainly of isolated flattened Golgi cisternae.
OBJECTIVE
To define a functional role for the HB of epididymal spermatozoa.
METHODS
Isolated fractions of HBs of epididymal spermatozoa were prepared and by quantitative tandem mass spectrometry revealed 1511 proteins.
RESULTS
The glucose transporter GLUT-3 was the most abundant protein followed by hexokinase 1, which along with the presence of all glycolytic enzymes suggested a role for the HB in glycolysis. Several TMED/p24 Golgi trafficking proteins were abundant with TMED7/p27 and TMED2/p24 defining the identity of the flattened cisternae within the HB as Golgi, along with the known Golgi proteins, GBF1, GOLPH3, Man2α1, and ManIIX. The Golgi trafficking protein TMED7/p27 via small 50-nm vesicles emanating from the Golgi cisternae was proposed to transport GLUT-3 to the plasma membrane for ATP production related to sperm motility. The internal membranes revealed abundant proteins not only of Golgi cisternae, but also of endoplasmic reticulum and endosomes. COPI and COPII coats, clathrin, SNAREs, annexins, atlastins, and GTPases were identified for vesicular trafficking and membrane fusion, in addition to ribosomes, stress proteins for protection, proteasome proteins involved in degradation, and cytoskeletal elements for migration of the HB along the flagellum. The biogenesis of the HB occurring at step 19 spermatids of the testis just prior to their release was uncovered as a key step in germ cell differentiation, where several proteins were expressed, some for the first time.
CONCLUSION
As epididymal spermatozoa undergo remodeling of their protein makeup through selective degradation of sperm proteins during epididymal transit, then remodeling as a consequence of new protein synthesis is not excluded by our observations.
Topics: Animals; Cell Differentiation; Epididymis; Glucose Transporter Type 3; Golgi Apparatus; Humans; Male; Protein Biosynthesis; Protein Transport; Sperm Maturation; Sperm Motility; Spermatozoa; Tandem Mass Spectrometry
PubMed: 31102346
DOI: 10.1111/andr.12641 -
Journal of Molecular Biology Aug 2016Glycosylation is a ubiquitous modification that occurs on proteins and lipids in all living cells. Consistent with their high complexity, glycans play crucial biological... (Review)
Review
Glycosylation is a ubiquitous modification that occurs on proteins and lipids in all living cells. Consistent with their high complexity, glycans play crucial biological roles in protein quality control and recognition events. Asparagine-linked protein N-glycosylation, the most complex glycosylation, initiates in the endoplasmic reticulum and matures in the Golgi apparatus. This process not only requires an accurate distribution of processing machineries, such as glycosyltransferases, glycosidases, and nucleotide sugar transporters, but also needs an efficient and well-organized factory that is responsible for the fidelity and quality control of sugar chain processing. In addition, accurate glycosylation must occur in coordination with protein trafficking and sorting. These activities are carried out by the Golgi apparatus, a membrane organelle in the center of the secretory pathway. To accomplish these tasks, the Golgi has developed into a unique stacked structure of closely aligned, flattened cisternae in which Golgi enzymes reside; in mammalian cells, dozens of Golgi stacks are often laterally linked into a ribbon-like structure. Here, we review our current knowledge of how the Golgi structure is formed and why its formation is required for accurate glycosylation, with the focus on how the Golgi stacking factors GRASP55 and GRASP65 generate the Golgi structure and how the conserved oligomeric Golgi complex maintains Golgi enzymes in different Golgi subcompartments by retrograde protein trafficking.
Topics: Animals; Biological Transport; Endoplasmic Reticulum; Glycosylation; Golgi Apparatus; Humans; Membrane Proteins; Protein Transport
PubMed: 26956395
DOI: 10.1016/j.jmb.2016.02.030 -
Methods in Molecular Biology (Clifton,... 2023The Golgi is a complex structure characterized by stacks of tightly aligned flat cisternae. In mammalian cells, Golgi stacks often concentrate in the perinuclear region...
The Golgi is a complex structure characterized by stacks of tightly aligned flat cisternae. In mammalian cells, Golgi stacks often concentrate in the perinuclear region and link together to form a ribbon. This structure is dynamic to accommodate continuous cargo flow in and out of the Golgi in both directions and undergoes morphological changes under physiological and pathological conditions. The fine, stacked Golgi structure makes it difficult to study by conventional light or even super-resolution microscopy. Furthermore, efforts to understand how Golgi structural dynamics impact cellular processes have been slow because of the knowledge gap in the protein machinery that maintains the complex and dynamic Golgi structure. In this method article, we list the common assays used in our research to help new and established researchers select the most appropriate method to properly address their questions.
Topics: Animals; Golgi Apparatus; Mammals
PubMed: 36512224
DOI: 10.1007/978-1-0716-2639-9_20 -
Cells Dec 2020Glycosylation is the most common post-translational modification of proteins; it mediates their correct folding and stability, as well as their transport through the... (Review)
Review
Glycosylation is the most common post-translational modification of proteins; it mediates their correct folding and stability, as well as their transport through the secretory transport. Changes in and linked glycans have been associated with multiple pathological conditions including congenital disorders of glycosylation, inflammatory diseases and cancer. Glycoprotein glycosylation at the Golgi involves the coordinated action of hundreds of glycosyltransferases and glycosidases, which are maintained at the correct location through retrograde vesicle trafficking between Golgi cisternae. In this review, we describe the molecular machinery involved in vesicle trafficking and tethering at the Golgi apparatus and the effects of mutations in the context of glycan biosynthesis and human diseases.
Topics: Animals; Glycoproteins; Glycoside Hydrolases; Glycosylation; Glycosyltransferases; Golgi Apparatus; Humans; Protein Stability; Protein Transport
PubMed: 33321764
DOI: 10.3390/cells9122652 -
The Journal of Cell Biology Dec 2001In this issue, Short et al. report the discovery of a protein named Golgin-45 that is located on the surface of the middle (or medial) cisternae of the Golgi complex.... (Review)
Review
In this issue, Short et al. report the discovery of a protein named Golgin-45 that is located on the surface of the middle (or medial) cisternae of the Golgi complex. Depletion of this protein disrupts the Golgi complex and leads to the return of a resident, lumenal, medial Golgi enzyme to the endoplasmic reticulum. These findings suggest that Golgin-45 serves as a linchpin for the maintenance of Golgi complex structure, and offer hints as to the mechanisms by which the polarized Golgi complex is constructed.
Topics: Animals; Golgi Apparatus; Humans; Membrane Proteins; Protein Transport
PubMed: 11739400
DOI: 10.1083/jcb.200109095