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Seminars in Cell & Developmental Biology Nov 2020In eukaryotic cells, protein sorting is a highly regulated mechanism important for many physiological events. After synthesis in the endoplasmic reticulum and... (Review)
Review
In eukaryotic cells, protein sorting is a highly regulated mechanism important for many physiological events. After synthesis in the endoplasmic reticulum and trafficking to the Golgi apparatus, proteins sort to many different cellular destinations including the endolysosomal system and the extracellular space. Secreted proteins need to be delivered directly to the cell surface. Sorting of secreted proteins from the Golgi apparatus has been a topic of interest for over thirty years, yet there is still no clear understanding of the machinery that forms the post-Golgi carriers. Most evidence points to these post-Golgi carriers being tubular pleomorphic structures that bud from the -face of the Golgi. In this review, we present the background studies and highlight the key components of this pathway, we then discuss the machinery implicated in the formation of these carriers, their translocation across the cytosol, and their fusion at the plasma membrane.
Topics: Animals; Cell Membrane; Golgi Apparatus; Humans; Lipid Metabolism; Membrane Fusion; Protein Transport; Secretory Pathway
PubMed: 32317144
DOI: 10.1016/j.semcdb.2020.04.001 -
Cell Apr 2021Cellular versatility depends on accurate trafficking of diverse proteins to their organellar destinations. For the secretory pathway (followed by approximately 30% of...
Cellular versatility depends on accurate trafficking of diverse proteins to their organellar destinations. For the secretory pathway (followed by approximately 30% of all proteins), the physical nature of the vessel conducting the first portage (endoplasmic reticulum [ER] to Golgi apparatus) is unclear. We provide a dynamic 3D view of early secretory compartments in mammalian cells with isotropic resolution and precise protein localization using whole-cell, focused ion beam scanning electron microscopy with cryo-structured illumination microscopy and live-cell synchronized cargo release approaches. Rather than vesicles alone, the ER spawns an elaborate, interwoven tubular network of contiguous lipid bilayers (ER exit site) for protein export. This receptacle is capable of extending microns along microtubules while still connected to the ER by a thin neck. COPII localizes to this neck region and dynamically regulates cargo entry from the ER, while COPI acts more distally, escorting the detached, accelerating tubular entity on its way to joining the Golgi apparatus through microtubule-directed movement.
Topics: Biological Transport, Active; COP-Coated Vesicles; Endoplasmic Reticulum; Golgi Apparatus; HeLa Cells; Humans; Microtubules; Protein Transport; Ubiquitin-Protein Ligases
PubMed: 33852913
DOI: 10.1016/j.cell.2021.03.035 -
ELife Apr 2024Mapping proteins in and associated with the Golgi apparatus reveals how this cellular compartment emerges in budding yeast and progresses over time.
Mapping proteins in and associated with the Golgi apparatus reveals how this cellular compartment emerges in budding yeast and progresses over time.
Topics: Golgi Apparatus; Saccharomycetales
PubMed: 38629949
DOI: 10.7554/eLife.97430 -
Proceedings of the National Academy of... May 2023The Golgi is a membrane-bound organelle that is essential for protein and lipid biosynthesis. It represents a central trafficking hub that sorts proteins and lipids to...
The Golgi is a membrane-bound organelle that is essential for protein and lipid biosynthesis. It represents a central trafficking hub that sorts proteins and lipids to various destinations or for secretion from the cell. The Golgi has emerged as a docking platform for cellular signaling pathways including LRRK2 kinase whose deregulation leads to Parkinson disease. Golgi dysfunction is associated with a broad spectrum of diseases including cancer, neurodegeneration, and cardiovascular diseases. To allow the study of the Golgi at high resolution, we report a rapid Golgi immunoprecipitation technique (Golgi-IP) to isolate intact Golgi mini-stacks for subsequent analysis of their content. By fusing the Golgi-resident protein TMEM115 to three tandem HA epitopes (GolgiTAG), we purified the Golgi using Golgi-IP with minimal contamination from other compartments. We then established an analysis pipeline using liquid chromatography coupled with mass spectrometry to characterize the human Golgi proteome, metabolome, and lipidome. Subcellular proteomics confirmed known Golgi proteins and identified proteins not previously associated with the Golgi. Metabolite profiling established the human Golgi metabolome and revealed the enrichment of uridine-diphosphate (UDP) sugars and their derivatives, which is consistent with their roles in protein and lipid glycosylation. Furthermore, targeted metabolomics validated SLC35A2 as the subcellular transporter for UDP-hexose. Finally, lipidomics analysis showed that phospholipids including phosphatidylcholine, phosphatidylinositol, and phosphatidylserine are the most abundant Golgi lipids and that glycosphingolipids are enriched in this compartment. Altogether, our work establishes a comprehensive molecular map of the human Golgi and provides a powerful method to study the Golgi with high precision in health and disease.
Topics: Humans; Golgi Apparatus; Chromatography, Liquid; Proteome; Lipids; Uridine Diphosphate
PubMed: 37155866
DOI: 10.1073/pnas.2219953120 -
Cell Reports Dec 2022STING, an endoplasmic reticulum (ER)-resident receptor for cyclic di-nucleotides (CDNs), is essential for innate immune responses. Upon CDN binding, STING moves from the...
STING, an endoplasmic reticulum (ER)-resident receptor for cyclic di-nucleotides (CDNs), is essential for innate immune responses. Upon CDN binding, STING moves from the ER to the Golgi, where it activates downstream type-I interferon (IFN) signaling. General cargo proteins exit from the ER via concentration at ER exit sites. However, the mechanism of STING concentration is poorly understood. Here, we visualize the ER exit sites of STING by blocking its transport at low temperature or by live-cell imaging with the cell-permeable ligand bis-SATE-2'F-c-di-dAMP, which we have developed. After ligand binding, STING forms punctate foci at non-canonical ER exit sites. Unbiased proteomic screens and super-resolution microscopy show that the Golgi-resident protein ACBD3/GCP60 recognizes and concentrates ligand-bound STING at specialized ER-Golgi contact sites. Depletion of ACBD3 impairs STING ER-to-Golgi trafficking and type-I IFN responses. Our results identify the ACBD3-mediated non-canonical cargo concentration system that drives the ER exit of STING.
Topics: Ligands; Proteomics; Membrane Proteins; Endoplasmic Reticulum; Golgi Apparatus; Interferon Type I; Protein Transport
PubMed: 36543137
DOI: 10.1016/j.celrep.2022.111868 -
Cell Structure and Function Aug 2019In research on cell biology, organelles have been a major unit of such analyses. Researchers have assumed that the inside of an organelle is almost uniform in regards to... (Review)
Review
In research on cell biology, organelles have been a major unit of such analyses. Researchers have assumed that the inside of an organelle is almost uniform in regards to its function, even though each organelle has multiple functions. However, we are now facing conundrums that cannot be resolved so long as we regard organelles as functionally uniform units. For instance, how can cells control the diverse patterns of glycosylation of various secretory proteins in the endoplasmic reticulum and Golgi in an orderly manner with high accuracy? Here, we introduce the novel concept of organelle zones as a solution; each organelle has functionally distinct zones, and zones in different organelles closely interact each other in order to perform complex cellular functions. This Copernican Revolution from organelle biology to organelle zone biology will drastically change and advance our thoughts about cells.Key words: organelle zone, contact site, ER stress, Golgi stress, organelle autoregulation.
Topics: Animals; Endoplasmic Reticulum; Golgi Apparatus; Humans; Organelles
PubMed: 31308351
DOI: 10.1247/csf.19010 -
Nature Methods Apr 2024Although StayGold is a bright and highly photostable fluorescent protein, its propensity for obligate dimer formation may hinder applications in molecular fusion and...
Although StayGold is a bright and highly photostable fluorescent protein, its propensity for obligate dimer formation may hinder applications in molecular fusion and membrane targeting. To attain monovalent as well as bright and photostable labeling, we engineered tandem dimers of StayGold to promote dispersibility. On the basis of the crystal structure of this fluorescent protein, we disrupted the dimerization to generate a monomeric variant that offers improved photostability and brightness compared to StayGold. We applied the new monovalent StayGold tools to live-cell imaging experiments using spinning-disk laser-scanning confocal microscopy or structured illumination microscopy. We achieved cell-wide, high-spatiotemporal resolution and sustained imaging of dynamic subcellular events, including the targeting of endogenous condensin I to mitotic chromosomes, the movement of the Golgi apparatus and its membranous derivatives along microtubule networks, the distribution of cortical filamentous actin and the remolding of cristae membranes within mobile mitochondria.
Topics: Mitochondria; Golgi Apparatus; Microtubules; Microscopy, Confocal
PubMed: 38036853
DOI: 10.1038/s41592-023-02085-6 -
Cells Sep 2020Conventional protein secretion in eukaryotic cells occurs via vesicular trafficking of proteins that are first targeted to the endoplasmic reticulum (ER), through the...
Conventional protein secretion in eukaryotic cells occurs via vesicular trafficking of proteins that are first targeted to the endoplasmic reticulum (ER), through the Golgi apparatus, and subsequently routed to the plasma membrane (PM), where membrane proteins take up residence while luminal proteins are released extracellularly [...].
Topics: Animals; Cell Membrane; Endoplasmic Reticulum; Fungi; Golgi Apparatus; Humans; Membrane Proteins; Plants; Protein Transport
PubMed: 32882862
DOI: 10.3390/cells9092009 -
Cell Reports Apr 2023STING is an endoplasmic reticulum-resident protein regulating innate immunity. After binding with cyclic guanosine monophosphate-AMP (cGAMP), STING translocates from the...
STING is an endoplasmic reticulum-resident protein regulating innate immunity. After binding with cyclic guanosine monophosphate-AMP (cGAMP), STING translocates from the endoplasmic reticulum (ER) to the Golgi apparatus to stimulate TBK1 and IRF3 activation, leading to expression of type I interferon. However, the exact mechanism concerning STING activation remains largely enigmatic. Here, we identify tripartite motif 10 (TRIM10) as a positive regulator of STING signaling. TRIM10-deficient macrophages exhibit reduced type I interferon production upon double-stranded DNA (dsDNA) or cGAMP stimulation and decreased resistance to herpes simplex virus 1 (HSV-1) infection. Additionally, TRIM10-deficient mice are more susceptible to HSV-1 infection and exhibit faster melanoma growth. Mechanistically, TRIM10 associates with STING and catalyzes K27- and K29-linked polyubiquitination of STING at K289 and K370, which promotes STING trafficking from the ER to the Golgi apparatus, formation of STING aggregates, and recruitment of TBK1 to STING, ultimately enhancing the STING-dependent type I interferon response. Our study defines TRIM10 as a critical activator in cGAS-STING-mediated antiviral and antitumor immunity.
Topics: Animals; Mice; DNA; Golgi Apparatus; Herpes Simplex; Immunity, Innate; Interferon Type I; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Nucleotidyltransferases; Tripartite Motif Proteins; Ubiquitin; Ubiquitin-Protein Ligases
PubMed: 36972172
DOI: 10.1016/j.celrep.2023.112306 -
Journal of Extracellular Vesicles Nov 2021The extracellular vesicle (EV) surface proteome (surfaceome) acts as a fundamental signalling gateway by bridging intra- and extracellular signalling networks, dictates...
The extracellular vesicle (EV) surface proteome (surfaceome) acts as a fundamental signalling gateway by bridging intra- and extracellular signalling networks, dictates EVs' capacity to communicate and interact with their environment, and is a source of potential disease biomarkers and therapeutic targets. However, our understanding of surface protein composition of large EVs (L-EVs, 100-800 nm, mean 310 nm, ATP5F1A, ATP5F1B, DHX9, GOT2, HSPA5, HSPD1, MDH2, STOML2), a major EV-subtype that are distinct from small EVs (S-EVs, 30-150 nm, mean 110 nm, CD44, CD63, CD81, CD82, CD9, PDCD6IP, SDCBP, TSG101) remains limited. Using a membrane impermeant derivative of biotin to capture surface proteins coupled to mass spectrometry analysis, we show that out of 4143 proteins identified in density-gradient purified L-EVs (1.07-1.11 g/mL, from multiple cancer cell lines), 961 proteins are surface accessible. The surface molecular diversity of L-EVs include (i) bona fide plasma membrane anchored proteins (cluster of differentiation, transporters, receptors and GPI anchored proteins implicated in cell-cell and cell-ECM interactions); and (ii) membrane surface-associated proteins (that are released by divalent ion chelator EDTA) implicated in actin cytoskeleton regulation, junction organization, glycolysis and platelet activation. Ligand-receptor analysis of L-EV surfaceome (e.g., ITGAV/ITGB1) uncovered interactome spanning 172 experimentally verified cognate binding partners (e.g., ANGPTL3, PLG, and VTN) with highest tissue enrichment for liver. Assessment of biotin inaccessible L-EV proteome revealed enrichment for proteins belonging to COPI/II-coated ER/Golgi-derived vesicles and mitochondria. Additionally, despite common surface proteins identified in L-EVs and S-EVs, our data reveals surfaceome heterogeneity between the two EV-subtype. Collectively, our study provides critical insights into diverse proteins operating at the interactive platform of L-EVs and molecular leads for future studies seeking to decipher L-EV heterogeneity and function.
Topics: Cell Line, Tumor; Chromatography, Liquid; Endoplasmic Reticulum; Extracellular Vesicles; Golgi Apparatus; Humans; Membrane Proteins; Mitochondria; Particle Size; Protein Transport; Proteome; Proteomics; Signal Transduction; Tandem Mass Spectrometry
PubMed: 34817906
DOI: 10.1002/jev2.12164