scholarly journals Pex3-mediated peroxisomal membrane contact sites in yeast

2020 ◽  
Author(s):  
Huala Wu
Keyword(s):  
Peroxisomal Membrane ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact

scholarly journals Peroxisomal Membrane Contact Sites in Yeasts

2021 ◽  
Vol 9 ◽  
Author(s):  
Amit S. Joshi
Keyword(s):  
Lipid Droplets ◽  
Peroxisome Biogenesis ◽  
Functional Importance ◽  
Peroxisomal Membrane ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Recent Developments ◽  
Membrane Contacts ◽  
Membrane Bound ◽  
Membrane Contact

Peroxisomes are ubiquitous, single membrane-bound organelles that play a crucial role in lipid metabolism and human health. While peroxisome number is maintained by the division of existing peroxisomes, nascent peroxisomes can be generated from the endoplasmic reticulum (ER) membrane in yeasts. During formation and proliferation, peroxisomes maintain membrane contacts with the ER. In addition to the ER, contacts between peroxisomes and other organelles such as lipid droplets, mitochondria, vacuole, and plasma membrane have been reported. These membrane contact sites (MCS) are dynamic and important for cellular function. This review focuses on the recent developments in peroxisome biogenesis and the functional importance of peroxisomal MCS in yeasts.

scholarly journals Fluorescent Tools to Analyze Peroxisome–Endoplasmic Reticulum Interactions in Mammalian Cells

Contact ◽  
2019 ◽  
Vol 2 ◽  
pp. 251525641984864 ◽  
Author(s):  
Alexa Bishop ◽  
Maki Kamoshita ◽  
Josiah B. Passmore ◽  
Christian Hacker ◽  
Tina A. Schrader ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Proximity Ligation Assay ◽  
Reporter System ◽  
Peroxisomal Membrane ◽  
Proximity Ligation ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact

Peroxisomes (POs) and the endoplasmic reticulum (ER) cooperate extensively in lipid-related metabolic pathways, and the ER also provides phospholipids to enable the peroxisomal membrane to expand prior to division. Recently, we identified peroxisomal proteins, ACBD5 and ACBD4, and the ER protein vesicle-associated membrane protein-associated protein-B (VAPB) as tethering components, which physically interact to foster PO–ER associations at membrane contact sites. Overexpression or loss of these tether proteins alters the extent of PO–ER interactions, impacting on lipid exchange between these two compartments. To facilitate further studies into PO–ER associations at the level of membrane contact sites, their role, composition, and regulation, we have developed two fluorescence-based systems to monitor PO–ER interactions. We modified a proximity ligation assay and a split-fluorescence reporter system using split superfolder green fluorescent protein. Using the proximity ligation assay, we were able to measure the changes in PO–ER interactions while the split-fluorescence reporter was more limited and only allowed us to label PO–ER contacts. We show that both techniques can be useful additions to the toolkit of methods to study PO–ER associations and explore the relative merits of each.

scholarly journals Peroxisome retention involves Inp1-dependent peroxisome–plasma membrane contact sites in yeast

2020 ◽  
Vol 219 (10) ◽  
Author(s):  
Arjen M. Krikken ◽  
Huala Wu ◽  
Rinse de Boer ◽  
Damien P. Devos ◽  
Tim P. Levine ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Hansenula Polymorpha ◽  
Peroxisomal Membrane ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
C Terminus ◽  
Latrunculin A ◽  
Membrane Contact ◽  
Mother Cells

Retention of peroxisomes in yeast mother cells requires Inp1, which is recruited to the organelle by the peroxisomal membrane protein Pex3. Here we show that Hansenula polymorpha Inp1 associates peroxisomes to the plasma membrane. Peroxisome–plasma membrane contact sites disappear upon deletion of INP1 but increase upon INP1 overexpression. Analysis of truncated Inp1 variants showed that the C terminus is important for association to the peroxisome, while a stretch of conserved positive charges and a central pleckstrin homology-like domain are important for plasma membrane binding. In cells of a PEX3 deletion, strain Inp1-GFP localizes to the plasma membrane, concentrated in patches near the bud neck and in the cortex of nascent buds. Upon disruption of the actin cytoskeleton by treatment of the cells with latrunculin A, Inp1-GFP became cytosolic, indicating that Inp1 localization is dependent on the presence of an intact actin cytoskeleton.

scholarly journals Caenorhabditis elegans Junctophilin has tissue-specific functions and regulates neurotransmission with extended-synaptotagmin

Genetics ◽  
2021 ◽  
Author(s):  
Christopher A Piggott ◽  
Zilu Wu ◽  
Stephen Nurrish ◽  
Suhong Xu ◽  
Joshua M Kaplan ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Calcium Channel ◽  
Tissue Specific ◽  
Voltage Gated ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Pharyngeal Muscles ◽  
Membrane Contact ◽  
Null Mutants

Abstract The junctophilin family of proteins tether together plasma membrane (PM) and endoplasmic reticulum (ER) membranes, and couple PM- and ER-localized calcium channels. Understanding in vivo functions of junctophilins is of great interest for dissecting the physiological roles of ER-PM contact sites. Here, we show that the sole C. elegans junctophilin JPH-1 localizes to discrete membrane contact sites in neurons and muscles and has important tissue-specific functions. jph-1 null mutants display slow growth and development due to weaker contraction of pharyngeal muscles, leading to reduced feeding. In the body wall muscle, JPH-1 co-localizes with the PM-localized EGL-19 voltage-gated calcium channel and ER-localized UNC-68/RyR calcium channel, and is required for animal movement. In neurons, JPH-1 co-localizes with the membrane contact site protein Extended-SYnaptoTagmin 2 (ESYT-2) in soma, and is present near presynaptic release sites. Interestingly, jph-1 and esyt-2 null mutants display mutual suppression in their response to aldicarb, suggesting that JPH-1 and ESYT-2 have antagonistic roles in neuromuscular synaptic transmission. Additionally, we find an unexpected cell non-autonomous effect of jph-1 in axon regrowth after injury. Genetic double mutant analysis suggests that jph-1 functions in overlapping pathways with two PM-localized voltage-gated calcium channels, egl-19 and unc-2, and unc-68/RyR for animal health and development. Finally, we show that jph-1 regulates the colocalization of EGL-19 and UNC-68 and that unc-68/RyR is required for JPH-1 localization to ER-PM puncta. Our data demonstrate important roles for junctophilin in cellular physiology, and also provide insights into how junctophilin functions together with other calcium channels in vivo.

scholarly journals Remodelling of Nucleus-Vacuole Junctions During Metabolic and Proteostatic Stress

Contact ◽  
2021 ◽  
Vol 4 ◽  
pp. 251525642110166
Author(s):  
Verena Kohler ◽  
Sabrina Büttner
Keyword(s):  
Nuclear Envelope ◽  
Internal Stress ◽  
Molecular Architecture ◽  
Adaptation To Stress ◽  
Semipermeable Membranes ◽  
Cellular Adaptation ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Intracellular Compartments ◽  
Membrane Contact

Cellular adaptation to stress and metabolic cues requires a coordinated response of different intracellular compartments, separated by semipermeable membranes. One way to facilitate interorganellar communication is via membrane contact sites, physical bridges between opposing organellar membranes formed by an array of tethering machineries. These contact sites are highly dynamic and establish an interconnected organellar network able to quickly respond to external and internal stress by changing size, abundance and molecular architecture. Here, we discuss recent work on nucleus-vacuole junctions, connecting yeast vacuoles with the nucleus. Appearing as small, single foci in mitotic cells, these contacts expand into one enlarged patch upon nutrient exhaustion and entry into quiescence or can be shaped into multiple large foci essential to sustain viability upon proteostatic stress at the nuclear envelope. We highlight the remarkable plasticity and rapid remodelling of these contact sites upon metabolic or proteostatic stress and their emerging importance for cellular fitness.

scholarly journals Synaptotagmins at the endoplasmic reticulum–plasma membrane contact sites maintain diacylglycerol homeostasis during abiotic stress

2021 ◽  
Author(s):  
Noemi Ruiz-Lopez ◽  
Jessica Pérez-Sancho ◽  
Alicia Esteban del Valle ◽  
Richard P Haslam ◽  
Steffen Vanneste ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Abiotic Stress ◽  
Fluorescent Protein ◽  
Mechanical Damage ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact ◽  
Green Fluorescent

Abstract Endoplasmic reticulum-plasma membrane contact sites (ER-PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER-PM protein tether synaptotagmin1 (SYT1) exhibit decreased plasma membrane (PM) integrity under multiple abiotic stresses such as freezing, high salt, osmotic stress and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER-PM tether that also functions in maintaining PM integrity. The ER-PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to wild type while the levels of most glycerolipid species remain unchanged. Additionally, the SYT1-green fluorescent protein (GFP) fusion preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work uncovers a SYT-dependent mechanism of stress adaptation counteracting the detrimental accumulation of diacylglycerol at the PM produced during episodes of abiotic stress.

Sign in / Sign up

Export Citation Format

Share Document