Pub Date : 2020-02-01DOI: 10.1177/2515256420908765
Nicolas Esnay, J. Dyer, R. Mullen, K. Chapman
Lipid droplets (LDs) are the principal subcellular sites for the storage of triacylglycerols (TAGs), and in plants, TAG degradation requires metabolism in peroxisomes. This metabolic cooperation includes TAG hydrolysis by the sugar-dependent 1 lipase located on the LD surface and the transfer of fatty acids into the peroxisome matrix by the peroxisomal membrane ATP-binding cassette transporter, PXA1. During seed germination, this process fuels heterotrophic growth and involves the retromer-dependent formation of peroxisomal membrane extensions called peroxules that interact with LDs. Similar changes in membrane architecture are also observed during interactions of peroxisomes and LDs in yeast and mammalian cells, despite differences in the molecular components required for their connections. Proteins directly involved in LD–peroxisome membrane contact site formation in plants have not yet been identified, but the connection between these two organelles is dependent upon PXA1, which contains a cytoplasmic exposed FFAT (two phenylalanines in an acidic tract)-like motif capable of interacting with vesicle-associated membrane protein-associated proteins (VAPs). Indeed, the identification of several VAPs in plant LD proteomes supports the premise that a VAP-PXA1 connection might be part of a functional tethering complex that connects these two organelles, although other types of interactions are also possible. Overall, such connections between peroxisomes and LDs would allow for efficient transfer of lipophilic substrates from LDs to the peroxisome matrix in plant cells, similar to how VAPs participate in lipid transfer reactions between other subcellular compartments in eukaryotic systems.
{"title":"Lipid Droplet–Peroxisome Connections in Plants","authors":"Nicolas Esnay, J. Dyer, R. Mullen, K. Chapman","doi":"10.1177/2515256420908765","DOIUrl":"https://doi.org/10.1177/2515256420908765","url":null,"abstract":"Lipid droplets (LDs) are the principal subcellular sites for the storage of triacylglycerols (TAGs), and in plants, TAG degradation requires metabolism in peroxisomes. This metabolic cooperation includes TAG hydrolysis by the sugar-dependent 1 lipase located on the LD surface and the transfer of fatty acids into the peroxisome matrix by the peroxisomal membrane ATP-binding cassette transporter, PXA1. During seed germination, this process fuels heterotrophic growth and involves the retromer-dependent formation of peroxisomal membrane extensions called peroxules that interact with LDs. Similar changes in membrane architecture are also observed during interactions of peroxisomes and LDs in yeast and mammalian cells, despite differences in the molecular components required for their connections. Proteins directly involved in LD–peroxisome membrane contact site formation in plants have not yet been identified, but the connection between these two organelles is dependent upon PXA1, which contains a cytoplasmic exposed FFAT (two phenylalanines in an acidic tract)-like motif capable of interacting with vesicle-associated membrane protein-associated proteins (VAPs). Indeed, the identification of several VAPs in plant LD proteomes supports the premise that a VAP-PXA1 connection might be part of a functional tethering complex that connects these two organelles, although other types of interactions are also possible. Overall, such connections between peroxisomes and LDs would allow for efficient transfer of lipophilic substrates from LDs to the peroxisome matrix in plant cells, similar to how VAPs participate in lipid transfer reactions between other subcellular compartments in eukaryotic systems.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"27 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78115371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1177/2515256420946627
V. Delfosse, W. Bourguet, G. Drin
Lipids are precisely distributed in the eukaryotic cell where they help to define organelle identity and function, in addition to their structural role. Once synthesized, many lipids must be delivered to other compartments by non-vesicular routes, a process that is undertaken by proteins called Lipid Transfer Proteins (LTPs). OSBP and the closely-related ORP and Osh proteins constitute a major, evolutionarily conserved family of LTPs in eukaryotes. Most of these target one or more subcellular regions, and membrane contact sites in particular, where two organelle membranes are in close proximity. It was initially thought that such proteins were strictly dedicated to sterol sensing or transport. However, over the last decade, numerous studies have revealed that these proteins have many more functions, and we have expanded our understanding of their mechanisms. In particular, many of them are lipid exchangers that exploit PI(4)P or possibly other phosphoinositide gradients to directionally transfer sterol or PS between two compartments. Importantly, these transfer activities are tightly coupled to processes such as lipid metabolism, cellular signalling and vesicular trafficking. This review describes the molecular architecture of OSBP/ORP/Osh proteins, showing how their specific structural features and internal configurations impart unique cellular functions.
{"title":"Structural and Functional Specialization of OSBP-Related Proteins","authors":"V. Delfosse, W. Bourguet, G. Drin","doi":"10.1177/2515256420946627","DOIUrl":"https://doi.org/10.1177/2515256420946627","url":null,"abstract":"Lipids are precisely distributed in the eukaryotic cell where they help to define organelle identity and function, in addition to their structural role. Once synthesized, many lipids must be delivered to other compartments by non-vesicular routes, a process that is undertaken by proteins called Lipid Transfer Proteins (LTPs). OSBP and the closely-related ORP and Osh proteins constitute a major, evolutionarily conserved family of LTPs in eukaryotes. Most of these target one or more subcellular regions, and membrane contact sites in particular, where two organelle membranes are in close proximity. It was initially thought that such proteins were strictly dedicated to sterol sensing or transport. However, over the last decade, numerous studies have revealed that these proteins have many more functions, and we have expanded our understanding of their mechanisms. In particular, many of them are lipid exchangers that exploit PI(4)P or possibly other phosphoinositide gradients to directionally transfer sterol or PS between two compartments. Importantly, these transfer activities are tightly coupled to processes such as lipid metabolism, cellular signalling and vesicular trafficking. This review describes the molecular architecture of OSBP/ORP/Osh proteins, showing how their specific structural features and internal configurations impart unique cellular functions.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"98 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82454147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1177/2515256419896965
Kamil Sołtysik, Y. Ohsaki, T. Fujimoto
The lipid droplet (LD) is a cytoplasmic organelle, but it also exists in the nucleus under some conditions or in some cell types. New studies have revealed that nuclear LDs do not occur by haphazard entry of cytoplasmic LDs. Instead, they are generated by specific mechanisms that are increasingly understood. The inner nuclear membrane (INM) plays a critical role in nuclear LD formation in both mammalian hepatocytes and budding yeast, although in significantly different ways. Hepatocyte nuclear LDs derive from precursors of very low-density lipoprotein lacking apolipoprotein B-100, which form in the endoplasmic reticulum lumen and accumulate in intranuclear extensions of the perinuclear space called type I nucleoplasmic reticulum. In contrast, nuclear LDs in yeast are generated by triglyceride synthesized in the INM. Nuclear LDs in hepatocytes and budding yeast are both instrumental in the regulation of phospholipid synthesis; however, again they function in different ways. As the full functional importance is as yet unknown, the close relationship of nuclear LDs and the INM is an attractive target of research from both physiological and pathological perspectives.
{"title":"Duo in a Mystical Realm—Nuclear Lipid Droplets and the Inner Nuclear Membrane","authors":"Kamil Sołtysik, Y. Ohsaki, T. Fujimoto","doi":"10.1177/2515256419896965","DOIUrl":"https://doi.org/10.1177/2515256419896965","url":null,"abstract":"The lipid droplet (LD) is a cytoplasmic organelle, but it also exists in the nucleus under some conditions or in some cell types. New studies have revealed that nuclear LDs do not occur by haphazard entry of cytoplasmic LDs. Instead, they are generated by specific mechanisms that are increasingly understood. The inner nuclear membrane (INM) plays a critical role in nuclear LD formation in both mammalian hepatocytes and budding yeast, although in significantly different ways. Hepatocyte nuclear LDs derive from precursors of very low-density lipoprotein lacking apolipoprotein B-100, which form in the endoplasmic reticulum lumen and accumulate in intranuclear extensions of the perinuclear space called type I nucleoplasmic reticulum. In contrast, nuclear LDs in yeast are generated by triglyceride synthesized in the INM. Nuclear LDs in hepatocytes and budding yeast are both instrumental in the regulation of phospholipid synthesis; however, again they function in different ways. As the full functional importance is as yet unknown, the close relationship of nuclear LDs and the INM is an attractive target of research from both physiological and pathological perspectives.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90579552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1177/2515256419865859
Andrés Norambuena, G. Bloom
A growing body of evidence supports the idea that organelles talk to each other. This communication is characterized by either physical interactions, functional associations mediated by signaling molecules, or both. This flow of information allows the orchestration of proper cellular metabolic responses to the ever-changing extracellular environment. Mitochondria, the cell’s principle metabolic factories, have emerged as a major player that not only influence the functions of other organelles, such as the endoplasmic reticulum, nuclei, and lysosomes, but as recently shown by our group, mitochondria also receive functionally critical information from lysosomes. This process was found to be mediated by the lysosome-associated mechanistic target of rapamycin complex 1, another major regulator of cellular metabolism. As discussed here, disruption of this lysosome-to-mitochondria signaling pathway may underlie the early pathogenesis of Alzheimer’s disease.
{"title":"A Novel Communication Pathway Between Lysosomes and Mitochondria Is Disrupted in Alzheimer’s Disease","authors":"Andrés Norambuena, G. Bloom","doi":"10.1177/2515256419865859","DOIUrl":"https://doi.org/10.1177/2515256419865859","url":null,"abstract":"A growing body of evidence supports the idea that organelles talk to each other. This communication is characterized by either physical interactions, functional associations mediated by signaling molecules, or both. This flow of information allows the orchestration of proper cellular metabolic responses to the ever-changing extracellular environment. Mitochondria, the cell’s principle metabolic factories, have emerged as a major player that not only influence the functions of other organelles, such as the endoplasmic reticulum, nuclei, and lysosomes, but as recently shown by our group, mitochondria also receive functionally critical information from lysosomes. This process was found to be mediated by the lysosome-associated mechanistic target of rapamycin complex 1, another major regulator of cellular metabolism. As discussed here, disruption of this lysosome-to-mitochondria signaling pathway may underlie the early pathogenesis of Alzheimer’s disease.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"167 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75977142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1177/2515256419856730
Laetitia Voilquin, M. Lodi, Thomas Di Mattia, M. Chenard, C. Mathelin, F. Alpy, C. Tomasetto
Intracellular cholesterol transport is a complex process involving specific carrier proteins. Cholesterol-binding proteins, such as the lipid transfer protein steroidogenic acute regulatory-related lipid transfer domain-3 (STARD3), are implicated in cholesterol movements between organelles. Indeed, STARD3 modulates intracellular cholesterol allocation by reducing it from the plasma membrane and favoring its passage from the endoplasmic reticulum (ER) to endosomes, where the protein is localized. STARD3 interacts with ER-anchored partners, notably vesicle-associated membrane protein-associated proteins (VAP-A and VAP-B) and motile sperm domain-containing 2 (MOSPD2), to create ER–endosome membrane contacts. Mechanistic studies showed that at ER–endosome contacts, STARD3 and VAP proteins build a molecular machine able to rapidly transfer cholesterol. This review presents the current knowledge on the molecular and cellular function of STARD3 in intracellular cholesterol traffic.
{"title":"STARD3: A Swiss Army Knife for Intracellular Cholesterol Transport","authors":"Laetitia Voilquin, M. Lodi, Thomas Di Mattia, M. Chenard, C. Mathelin, F. Alpy, C. Tomasetto","doi":"10.1177/2515256419856730","DOIUrl":"https://doi.org/10.1177/2515256419856730","url":null,"abstract":"Intracellular cholesterol transport is a complex process involving specific carrier proteins. Cholesterol-binding proteins, such as the lipid transfer protein steroidogenic acute regulatory-related lipid transfer domain-3 (STARD3), are implicated in cholesterol movements between organelles. Indeed, STARD3 modulates intracellular cholesterol allocation by reducing it from the plasma membrane and favoring its passage from the endoplasmic reticulum (ER) to endosomes, where the protein is localized. STARD3 interacts with ER-anchored partners, notably vesicle-associated membrane protein-associated proteins (VAP-A and VAP-B) and motile sperm domain-containing 2 (MOSPD2), to create ER–endosome membrane contacts. Mechanistic studies showed that at ER–endosome contacts, STARD3 and VAP proteins build a molecular machine able to rapidly transfer cholesterol. This review presents the current knowledge on the molecular and cellular function of STARD3 in intracellular cholesterol traffic.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"292 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88320427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-05-01DOI: 10.1177/2515256419847407
B. Delprat, J. Rieusset, C. Delettre
Interactions between endoplasmic reticulum (ER) and mitochondria are key components of essential cellular functions. Indeed, these membrane appositions are necessary for proper Ca2+ transfer from ER to mitochondria, to regulate lipid metabolism, apoptosis, and inflammation. We report that the ER protein WFS1 interacts with the neuronal calcium sensor protein NCS1 to regulate mitochondria associated-ER membrane formation. Mutations in the WFS1 gene are associated with Wolfram syndrome, a rare neurodegenerative disease. We demonstrated that human WFS1-deficient cells lack NCS1 and fail to tether ER and mitochondria, resulting in a decrease in Ca2+ transfer and mitochondrial respiration. Interestingly, we showed that NCS1 overexpression in WFS1-deficient cells restored ER–mitochondria interactions and calcium exchange. Our results suggest that WFS1 regulates ER tethering to mitochondria through NCS1 and that restoration of NCS1 expression could be a therapeutic tool for restoring calcium signaling at the mitochondria associated-ER membrane interface and mitochondrial function in Wolfram syndrome.
{"title":"Defective Endoplasmic Reticulum–Mitochondria Connection Is a Hallmark of Wolfram Syndrome","authors":"B. Delprat, J. Rieusset, C. Delettre","doi":"10.1177/2515256419847407","DOIUrl":"https://doi.org/10.1177/2515256419847407","url":null,"abstract":"Interactions between endoplasmic reticulum (ER) and mitochondria are key components of essential cellular functions. Indeed, these membrane appositions are necessary for proper Ca2+ transfer from ER to mitochondria, to regulate lipid metabolism, apoptosis, and inflammation. We report that the ER protein WFS1 interacts with the neuronal calcium sensor protein NCS1 to regulate mitochondria associated-ER membrane formation. Mutations in the WFS1 gene are associated with Wolfram syndrome, a rare neurodegenerative disease. We demonstrated that human WFS1-deficient cells lack NCS1 and fail to tether ER and mitochondria, resulting in a decrease in Ca2+ transfer and mitochondrial respiration. Interestingly, we showed that NCS1 overexpression in WFS1-deficient cells restored ER–mitochondria interactions and calcium exchange. Our results suggest that WFS1 regulates ER tethering to mitochondria through NCS1 and that restoration of NCS1 expression could be a therapeutic tool for restoring calcium signaling at the mitochondria associated-ER membrane interface and mitochondrial function in Wolfram syndrome.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"105 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77624272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1177/2515256419840528
V. Olkkonen
The study commented here reports that the OSBP homologue ORP4L is aberrantly induced in CD34+CD38− leukemia stem cells (LSCs) of patients with acute myeloid leukemia and acts as an accessory factor for phospholipase C β3 (PLCβ3), a PLC isoform with a dominant role in these cells. Our mechanistic data suggest that ORP4L extracts and presents PI4,5P2 for catalysis by PLCβ3, thus controlling Ca2+ oscillations, bioenergetics, and survival of the cells. A small molecular compound LYZ-81 is described as a specific inhibitor of ORP4L, which can be employed to eradicate LSCs in vitro and in vivo in NOD/SCID mice. Our observations identify ORP4L as a potential target for new leukemia therapies.
{"title":"ORP4L: Can Targeting an MCS Component Provide Tools for Eradication of Leukemia?","authors":"V. Olkkonen","doi":"10.1177/2515256419840528","DOIUrl":"https://doi.org/10.1177/2515256419840528","url":null,"abstract":"The study commented here reports that the OSBP homologue ORP4L is aberrantly induced in CD34+CD38− leukemia stem cells (LSCs) of patients with acute myeloid leukemia and acts as an accessory factor for phospholipase C β3 (PLCβ3), a PLC isoform with a dominant role in these cells. Our mechanistic data suggest that ORP4L extracts and presents PI4,5P2 for catalysis by PLCβ3, thus controlling Ca2+ oscillations, bioenergetics, and survival of the cells. A small molecular compound LYZ-81 is described as a specific inhibitor of ORP4L, which can be employed to eradicate LSCs in vitro and in vivo in NOD/SCID mice. Our observations identify ORP4L as a potential target for new leukemia therapies.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73949124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1177/2515256419877091
T. Levine, F. Perez, Yasunori Saheki, J. von Blume
On May 29, 2019, at the Osaka University Hospital, Japan, the “Organelle Zones” research grant group (see http://organellezone.org/english/) organized a 1 day symposium for its own members and four guest speakers, with about 60 attendees. The research group studies three different ways in which regions within organelles carry out functions distinct from other parts of the organelle. Work at this suborganellar level is increasingly recognized as an important aspect of cell biology. The group’s projects are divided into these themes with 9 Principal Investigators and 18 Coinvestigators over 5 years. The symposium followed a similar meeting in 2018 and had four speakers from within the consortium as well as the external speakers. The talks were divided into three sessions, each showcasing one way of subcompartmentalizing organelles into zones.
{"title":"Meeting Report From the 2019 “Organelle Zone” Symposium in Osaka, Japan","authors":"T. Levine, F. Perez, Yasunori Saheki, J. von Blume","doi":"10.1177/2515256419877091","DOIUrl":"https://doi.org/10.1177/2515256419877091","url":null,"abstract":"On May 29, 2019, at the Osaka University Hospital, Japan, the “Organelle Zones” research grant group (see http://organellezone.org/english/) organized a 1 day symposium for its own members and four guest speakers, with about 60 attendees. The research group studies three different ways in which regions within organelles carry out functions distinct from other parts of the organelle. Work at this suborganellar level is increasingly recognized as an important aspect of cell biology. The group’s projects are divided into these themes with 9 Principal Investigators and 18 Coinvestigators over 5 years. The symposium followed a similar meeting in 2018 and had four speakers from within the consortium as well as the external speakers. The talks were divided into three sessions, each showcasing one way of subcompartmentalizing organelles into zones.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"56 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77551505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1177/2515256419829623
Huala Wu, I. J. van der Klei
Peroxisomes are important organelles and present in almost all eukaryotic cells. Close associations between peroxisomes and other cell compartments are known for several decades. The first molecular details of physical contacts between peroxisomes and various other organelles are now beginning to emerge. We recently described a novel contact between peroxisomes and vacuoles in the yeast Hansenula polymorpha, which develops during conditions of strong peroxisome proliferation. At such conditions, Pex3-GFP forms focal patches at the peroxisome–vacuole contacts, while overproduction of Pex3 promotes their formation. These results reveal a novel function for Pex3 in the formation of these contacts, where it might act as a tethering protein. We speculate that the peroxisome–vacuole contact is important for membrane lipid transfer at conditions of strong organellar expansion.
{"title":"Novel Peroxisome–Vacuole Contacts in Yeast","authors":"Huala Wu, I. J. van der Klei","doi":"10.1177/2515256419829623","DOIUrl":"https://doi.org/10.1177/2515256419829623","url":null,"abstract":"Peroxisomes are important organelles and present in almost all eukaryotic cells. Close associations between peroxisomes and other cell compartments are known for several decades. The first molecular details of physical contacts between peroxisomes and various other organelles are now beginning to emerge. We recently described a novel contact between peroxisomes and vacuoles in the yeast Hansenula polymorpha, which develops during conditions of strong peroxisome proliferation. At such conditions, Pex3-GFP forms focal patches at the peroxisome–vacuole contacts, while overproduction of Pex3 promotes their formation. These results reveal a novel function for Pex3 in the formation of these contacts, where it might act as a tethering protein. We speculate that the peroxisome–vacuole contact is important for membrane lipid transfer at conditions of strong organellar expansion.","PeriodicalId":87951,"journal":{"name":"Contact","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84033582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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