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Chitin Synthesis in Yeast: A Matter of Trafficking. Int J Mol Sci 2022; 23:ijms232012251. [PMID: 36293107 PMCID: PMC9603707 DOI: 10.3390/ijms232012251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 01/24/2023] Open
Abstract
Chitin synthesis has attracted scientific interest for decades as an essential part of fungal biology and for its potential as a target for antifungal therapies. While this interest remains, three decades ago, pioneering molecular studies on chitin synthesis regulation identified the major chitin synthase in yeast, Chs3, as an authentic paradigm in the field of the intracellular trafficking of integral membrane proteins. Over the years, researchers have shown how the intracellular trafficking of Chs3 recapitulates all the steps in the intracellular trafficking of integral membrane proteins, from their synthesis in the endoplasmic reticulum to their degradation in the vacuole. This trafficking includes specific mechanisms for sorting in the trans-Golgi network, regulated endocytosis, and endosomal recycling at different levels. This review summarizes the work carried out on chitin synthesis regulation, mostly focusing on Chs3 as a molecular model to study the mechanisms involved in the control of the intracellular trafficking of proteins.
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Purkanti R, Thattai M. Genome doubling enabled the expansion of yeast vesicle traffic pathways. Sci Rep 2022; 12:11213. [PMID: 35780185 PMCID: PMC9250509 DOI: 10.1038/s41598-022-15419-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Vesicle budding and fusion in eukaryotes depend on a suite of protein types, such as Arfs, Rabs, coats and SNAREs. Distinct paralogs of these proteins act at distinct intracellular locations, suggesting a link between gene duplication and the expansion of vesicle traffic pathways. Genome doubling, a common source of paralogous genes in fungi, provides an ideal setting in which to explore this link. Here we trace the fates of paralog doublets derived from the 100-Ma-old hybridization event that gave rise to the whole genome duplication clade of budding yeast. We find that paralog doublets involved in specific vesicle traffic functions and pathways are convergently retained across the entire clade. Vesicle coats and adaptors involved in secretory and early-endocytic pathways are retained as doublets, at rates several-fold higher than expected by chance. Proteins involved in later endocytic steps and intra-Golgi traffic, including the entire set of multi-subunit and coiled-coil tethers, have reverted to singletons. These patterns demonstrate that selection has acted to expand and diversify the yeast vesicle traffic apparatus, across species and time.
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Affiliation(s)
- Ramya Purkanti
- Center for Integrative Genomics, Université de Lausanne, Lausanne, Switzerland
| | - Mukund Thattai
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India.
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Moro S, Moscoso-Romero E, Poddar A, Mulet JM, Perez P, Chen Q, Valdivieso MH. Exomer Is Part of a Hub Where Polarized Secretion and Ionic Stress Connect. Front Microbiol 2021; 12:708354. [PMID: 34349749 PMCID: PMC8326576 DOI: 10.3389/fmicb.2021.708354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/18/2021] [Indexed: 11/13/2022] Open
Abstract
Plasma membrane and membranous organelles contribute to the physiology of the Eukaryotic cell by participating in vesicle trafficking and the maintenance of ion homeostasis. Exomer is a protein complex that facilitates vesicle transport from the trans-Golgi network to the plasma membrane, and its absence leads to the retention of a set of selected cargoes in this organelle. However, this retention does not explain all phenotypes observed in exomer mutants. The Schizosaccharomyces pombe exomer is composed of Cfr1 and Bch1, and cfr1Δ and bch1Δ were sensitive to high concentrations of potassium salts but not sorbitol, which showed sensitivity to ionic but not osmotic stress. Additionally, the activity of the plasma membrane ATPase was higher in exomer mutants than in the wild-type, pointing to membrane hyperpolarization, which caused an increase in intracellular K+ content and mild sensitivity to Na+, Ca2+, and the aminoglycoside antibiotic hygromycin B. Moreover, in response to K+ shock, the intracellular Ca2+ level of cfr1Δ cells increased significantly more than in the wild-type, likely due to the larger Ca2+ spikes in the mutant. Microscopy analyses showed a defective endosomal morphology in the mutants. This was accompanied by an increase in the intracellular pools of the K+ exporting P-type ATPase Cta3 and the plasma membrane Transient Receptor Potential (TRP)-like Ca2+ channel Pkd2, which were partially diverted from the trans-Golgi network to the prevacuolar endosome. Despite this, most Cta3 and Pkd2 were delivered to the plasma membrane at the cell growing sites, showing that their transport from the trans-Golgi network to the cell surface occurred in the absence of exomer. Nevertheless, shortly after gene expression in the presence of KCl, the polarized distribution of Cta3 and Pkd2 in the plasma membrane was disturbed in the mutants. Finally, the use of fluorescent probes suggested that the distribution and dynamics of association of some lipids to the plasma membrane in the presence of KCl were altered in the mutants. Thus, exomer participation in the response to K+ stress was multifaceted. These results supported the notion that exomer plays a general role in protein sorting at the trans-Golgi network and in polarized secretion, which is not always related to a function as a selective cargo adaptor.
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Affiliation(s)
- Sandra Moro
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Esteban Moscoso-Romero
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Abhishek Poddar
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Jose M Mulet
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Pilar Perez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Salamanca, Spain
| | - Qian Chen
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - M-Henar Valdivieso
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
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Anton-Plagaro C, Sanchez N, Valle R, Mulet JM, Duncan MC, Roncero C. Exomer complex regulates protein traffic at the TGN through differential interactions with cargos and clathrin adaptor complexes. FASEB J 2021; 35:e21615. [PMID: 33978245 DOI: 10.1096/fj.202002610r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 12/16/2022]
Abstract
Protein sorting at the trans-Golgi network (TGN) usually requires the assistance of cargo adaptors. However, it remains to be examined how the same complex can mediate both the export and retention of different proteins or how sorting complexes interact among themselves. In Saccharomyces cerevisiae, the exomer complex is involved in the polarized transport of some proteins from the TGN to the plasma membrane (PM). Intriguingly, exomer and its cargos also show a sort of functional relationship with TGN clathrin adaptors that is still unsolved. Here, using a wide range of techniques, including time-lapse and BIFC microscopy, we describe new molecular implications of the exomer complex in protein sorting and address its different layers of functional interaction with clathrin adaptor complexes. Exomer mutants show impaired amino acid uptake because it facilitates not only the polarized delivery of amino acid permeases to the PM but also participates in their endosomal traffic. We propose a model for exomer where it modulates the recruitment of TGN clathrin adaptors directly or indirectly through the Arf1 function. Moreover, we describe an in vivo competitive relationship between the exomer and AP-1 complexes for the model cargo Chs3. These results highlight a broad role for exomer in regulating protein sorting at the TGN that is complementary to its role as cargo adaptor and present a model to understand the complexity of TGN protein sorting.
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Affiliation(s)
- Carlos Anton-Plagaro
- Instituto de Biología Funcional y Genómica (IBFG) and Departamento de Microbiología y Genética, CSIC-Universidad de Salamanca, Salamanca, Spain
| | - Noelia Sanchez
- Instituto de Biología Funcional y Genómica (IBFG) and Departamento de Microbiología y Genética, CSIC-Universidad de Salamanca, Salamanca, Spain
| | - Rosario Valle
- Instituto de Biología Funcional y Genómica (IBFG) and Departamento de Microbiología y Genética, CSIC-Universidad de Salamanca, Salamanca, Spain
| | - Jose Miguel Mulet
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universitat Politècnica de València, Valencia, Spain
| | - Mara C Duncan
- Cell and Developmental Biology Department, University of Michigan, Ann Arbor, MI, USA
| | - Cesar Roncero
- Instituto de Biología Funcional y Genómica (IBFG) and Departamento de Microbiología y Genética, CSIC-Universidad de Salamanca, Salamanca, Spain
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Makowski SL, Kuna RS, Field SJ. Induction of membrane curvature by proteins involved in Golgi trafficking. Adv Biol Regul 2019; 75:100661. [PMID: 31668661 PMCID: PMC7056495 DOI: 10.1016/j.jbior.2019.100661] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/22/2022]
Abstract
The Golgi apparatus serves a key role in processing and sorting lipids and proteins for delivery to their final cellular destinations. Vesicle exit from the Golgi initiates with directional deformation of the lipid bilayer to produce a bulge. Several mechanisms have been described by which lipids and proteins can induce directional membrane curvature to promote vesicle budding. Here we review some of the mechanisms implicated in inducing membrane curvature at the Golgi to promote vesicular trafficking to various cellular destinations.
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Affiliation(s)
- Stefanie L Makowski
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ramya S Kuna
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Seth J Field
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA.
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