contact sites
Recently Published Documents


TOTAL DOCUMENTS

900
(FIVE YEARS 347)

H-INDEX

84
(FIVE YEARS 18)

2022 ◽  
Author(s):  
Hannah E Krawczyk ◽  
Siqi Sun ◽  
Nathan Doner ◽  
Qiqi Yan ◽  
Magdiel Sheng Satha Lim ◽  
...  

Membrane contact sites (MCS) are inter-organellar connections that allow for the direct exchange of molecules, such as lipids or Ca2+ between organelles, but can also serve to tether organelles at specific locations within cells. Here we identified and characterised three proteins that form a lipid droplet (LD)-plasma membrane (PM) tethering complex in plant cells, namely LD-localised SEED LD PROTEIN (SLDP) 1 and 2 and PM-localised LD-PLASMA MEMBRANE ADAPTOR (LIPA). Using proteomics and different protein-protein interaction assays, we show that both SLDPs associate with LIPA. Disruption of either SLDP1 and 2 expression, or that of LIPA, leads to an aberrant clustering of LDs in Arabidopsis seedlings. Ectopic co-expression of one of the SLDPs with LIPA on the other hand is sufficient to reconstitute LD-PM tethering in Nicotiana tabacum pollen tubes, a cell type characterised by dynamically moving LDs in the cytosolic streaming. Further, confocal laser scanning microscopy revealed both SLDP2.1 and LIPA to be enriched at LD-PM contact sites in seedlings. These and other results suggest that SLDP and LIPA interact to form a tethering complex that anchors a subset of LDs to the PM during post-germinative seedling growth in Arabidopsis thaliana.


2022 ◽  
Vol 221 (3) ◽  
Author(s):  
Suzan Kors ◽  
Christian Hacker ◽  
Chloe Bolton ◽  
Renate Maier ◽  
Lena Reimann ◽  
...  

Peroxisomes and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism. They form membrane contacts through interaction of the peroxisomal membrane protein ACBD5 (acyl-coenzyme A–binding domain protein 5) and the ER-resident protein VAPB (vesicle-associated membrane protein–associated protein B). ACBD5 binds to the major sperm protein domain of VAPB via its FFAT-like (two phenylalanines [FF] in an acidic tract) motif. However, molecular mechanisms, which regulate formation of these membrane contact sites, are unknown. Here, we reveal that peroxisome–ER associations via the ACBD5-VAPB tether are regulated by phosphorylation. We show that ACBD5-VAPB binding is phosphatase-sensitive and identify phosphorylation sites in the flanking regions and core of the FFAT-like motif, which alter interaction with VAPB—and thus peroxisome–ER contact sites—differently. Moreover, we demonstrate that GSK3β (glycogen synthase kinase-3 β) regulates this interaction. Our findings reveal for the first time a molecular mechanism for the regulation of peroxisome–ER contacts in mammalian cells and expand the current model of FFAT motifs and VAP interaction.


2022 ◽  
Vol 221 (3) ◽  
Author(s):  
Alexandre Toulmay ◽  
Fawn B. Whittle ◽  
Jerry Yang ◽  
Xiaofei Bai ◽  
Jessica Diarra ◽  
...  

Glycosylphosphatidylinositol (GPI) is a glycolipid membrane anchor found on surface proteins in all eukaryotes. It is synthesized in the ER membrane. Each GPI anchor requires three molecules of ethanolamine phosphate (P-Etn), which are derived from phosphatidylethanolamine (PE). We found that efficient GPI anchor synthesis in Saccharomyces cerevisiae requires Csf1; cells lacking Csf1 accumulate GPI precursors lacking P-Etn. Structure predictions suggest Csf1 is a tube-forming lipid transport protein like Vps13. Csf1 is found at contact sites between the ER and other organelles. It interacts with the ER protein Mcd4, an enzyme that adds P-Etn to nascent GPI anchors, suggesting Csf1 channels PE to Mcd4 in the ER at contact sites to support GPI anchor biosynthesis. CSF1 has orthologues in Caenorhabditis elegans (lpd-3) and humans (KIAA1109/TWEEK); mutations in KIAA1109 cause the autosomal recessive neurodevelopmental disorder Alkuraya-Kučinskas syndrome. Knockout of lpd-3 and knockdown of KIAA1109 reduced GPI-anchored proteins on the surface of cells, suggesting Csf1 orthologues in human cells support GPI anchor biosynthesis.


2022 ◽  
Vol 11 (1) ◽  
Author(s):  
Wendelin Moser ◽  
Annour Adoum Batil ◽  
Rebekka Ott ◽  
Moussa Abderamane ◽  
Ruth Clements ◽  
...  

Abstract Background Researching a water-borne disease in the middle of the Sahara desert might not seem the most relevant concern. However, nomadic Sahelian pastoralists health concerns regarding their livestock and anecdotal reports about trematode infections of Fasciola spp. and Schistosoma spp. in desert-raised animals justified an exploratory study focusing on the lakes of Ounianga in Northern Chad. The aim was to test whether trematode parasites such as Schistosoma spp. occur in human populations living around the Sahara desert lakes of Ounianga Kebir and Ounianga Serir in northern Chad. Methods The study was carried out in January 2019 and comprised of three components. First, a cross sectional survey based on a random sample drawn from the population to detect infections with S. haematobium and S. mansoni; second, focus group discussions exploring disease priorities, access to health and health seeking behaviour; and third, surveying water contact sites for intermediate host snails. Samples of trematode parasites and snails were confirmed on species level by molecular genetic methods. For parasitological and malacological surveys descriptive statistics were performed. Qualitative data analysis included the full review of all transcripts, followed by a descriptive and explorative thematic analysis. Results Among 258 participants, the overall S. haematobium prevalence using urine filtration was 39.2% [95% confidence interval (CI): 33.5–45.1%], with 51.5% of the infected suffering from heavy infection. The intermediate host snail of S. haematobium (Bulinus truncatus) occurred at water contact sites near both study villages, revealing the potential for local transmission. Although a positive S. mansoni point-of-care circulating cathodic antigen (POC-CCA) test result was obtained from 8.6% (95% CI 5.7–12.8%) of the samples, no intermediate host snails of S. mansoni were found, and the relevance of S. mansoni remains uncertain. Qualitative findings underline the importance of morbidity caused by urinary schistosomiasis, and the lack of access to diagnostics and treatment as a major health concern. Conclusions This research revealed a high prevalence of urinary schistosomiasis in the population living around the lakes of Ounianga in the Sahara, a United Nations Educational, Scientific and Cultural Organization (UNESCO) world heritage site in Chad. Despite the high public health importance of the associated morbidity expressed by the population, there is no access to diagnostics and treatment. Further work is needed to develop and test a context-adapted intervention. Graphical Abstract


Cell Reports ◽  
2022 ◽  
Vol 38 (2) ◽  
pp. 110213 ◽  
Author(s):  
Yoann Combot ◽  
Veijo T. Salo ◽  
Gilliane Chadeuf ◽  
Maarit Hölttä ◽  
Katharina Ven ◽  
...  

2021 ◽  
Vol 221 (2) ◽  
Author(s):  
Albert Lu ◽  
Frank Hsieh ◽  
Bikal R. Sharma ◽  
Sydney R. Vaughn ◽  
Carlos Enrich ◽  
...  

We report here two genome-wide CRISPR screens performed to identify genes that, when knocked out, alter levels of lysosomal cholesterol or bis(monoacylglycero)phosphate. In addition, these screens were also performed under conditions of NPC1 inhibition to identify modifiers of NPC1 function in lysosomal cholesterol export. The screens confirm tight coregulation of cholesterol and bis(monoacylglycero)phosphate in cells and reveal an unexpected role for the ER-localized SNX13 protein as a negative regulator of lysosomal cholesterol export and contributor to ER–lysosome membrane contact sites. In the absence of NPC1 function, SNX13 knockdown redistributes lysosomal cholesterol and is accompanied by triacylglycerol-rich lipid droplet accumulation and increased lysosomal bis(monoacylglycero)phosphate. These experiments provide unexpected insight into the regulation of lysosomal lipids and modification of these processes by novel gene products.


2021 ◽  
Vol 221 (1) ◽  
Author(s):  
Louise H. Wong ◽  
Andrea Martello ◽  
Emily R. Eden

Heterogeneity in endosomal membrane phospholipid content is emerging as a regulator of endocytic trafficking pathways. Kawasaki et al. (2021. J. Cell. Biol.https://doi.org/10.1083/jcb.202103141) demonstrate exchange of endosomal PI4P for PS by ORP10 at ER–endosome contact sites, with the consequent recruitment of endosomal fission factors.


Author(s):  
Aarya Bomanwar ◽  
Chandra Veer Singh

Septal reconstruction has many needs and usages. Nowadays, people are very concerned about looking and would like to correct them. Septal reconstruction has been immensely used in the field of cosmetics. A successful septoplasty would lead us to know about the pathology of the septum by which we can avoid further complications. It would be further significant in nasal obstruction or difficulty in breathing. Deviation of the nasal septum can also be corrected by septal   reconstruction by various techniques used for septoplasty. Complete septal reconstruction is the best method for extreme S-shaped and wave-like deviations or multiple fractures. The septoplasty is performed endonasal for caudal septal deviation. Traction sutures to rectify the caudal septum deviation is another type of surgery. Septoplasty usually opens the way for all other rhinoplasty procedures, as a straight, stable septum reflects the attractiveness and functionality of the nose. The patient's history and the surgeon's expertise play a favorable outcome. In conjunction with other nose procedures, such as cosmetic rhinoplasty and endoscopic sinus surgery, Septoplasty is frequently done to alleviate nasal airway obstruction or headaches induced by rhinology irritation produced by touch. Endoscopic septoplasty requires the same amount of time and delivers equal, if not better, results than previous procedures. Visualization is vastly improved by endoscopic technology. Isolated deviation, spurs, perforations, and contact sites are examples of distinct septal disorders that can be treated individually using this procedure. In this review article, the importance of traction sutures is mentioned. The article gives us an idea about Septoplasty and how it can be achieved, its complications, risk factors, and a few postoperative points.


Sign in / Sign up

Export Citation Format

Share Document