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Nature Communications Jun 2024Autophagy is relevant for diverse processes in eukaryotic cells, making its regulation of fundamental importance. The formation and maturation of autophagosomes require...
Autophagy is relevant for diverse processes in eukaryotic cells, making its regulation of fundamental importance. The formation and maturation of autophagosomes require a complex choreography of numerous factors. The endosomal sorting complex required for transport (ESCRT) is implicated in the final step of autophagosomal maturation by sealing of the phagophore membrane. ESCRT-III components were shown to mediate membrane scission by forming filaments that interact with cellular membranes. However, the molecular mechanisms underlying the recruitment of ESCRTs to non-endosomal membranes remain largely unknown. Here we focus on the ESCRT-associated protein ALG2-interacting protein X (ALIX) and identify Ca-dependent lipid binding protein 1 (CaLB1) as its interactor. Our findings demonstrate that CaLB1 interacts with AUTOPHAGY8 (ATG8) and PI(3)P, a phospholipid found in autophagosomal membranes. Moreover, CaLB1 and ALIX localize with ATG8 on autophagosomes upon salt treatment and assemble together into condensates. The depletion of CaLB1 impacts the maturation of salt-induced autophagosomes and leads to reduced delivery of autophagosomes to the vacuole. Here, we propose a crucial role of CaLB1 in augmenting phase separation of ALIX, facilitating the recruitment of ESCRT-III to the site of phagophore closure thereby ensuring efficient maturation of autophagosomes.
Topics: Arabidopsis; Autophagosomes; Endosomal Sorting Complexes Required for Transport; Arabidopsis Proteins; Calcium-Binding Proteins; Autophagy; Phosphatidylinositol Phosphates; Autophagy-Related Protein 8 Family; Vacuoles; Phase Separation
PubMed: 38898014
DOI: 10.1038/s41467-024-49485-6 -
Journal of Biochemistry Jun 2024Cytidine diphosphate diacylglycerol (CDP-DAG) is a critical intermediate that is converted to multiple phospholipids in prokaryotes and eukaryotes. In budding yeast,...
Cytidine diphosphate diacylglycerol (CDP-DAG) is a critical intermediate that is converted to multiple phospholipids in prokaryotes and eukaryotes. In budding yeast, CDP-DAG synthesis from cytidine triphosphate (CTP) and phosphatidic acid (PA) is catalyzed by the membrane-integrated protein Cds1 in the endoplasmic reticulum and the peripheral membrane-bound protein Tam41 in mitochondria. Although a recent study revealed that the fission yeast SpTam41 consists of a nucleotidyltransferase domain and a winged helix domain, forming an active-site pocket for CTP binding between the two domains together with a C-terminal amphipathic helix for membrane association, how CTP and Mg2+, a most-favored divalent cation, are accommodated with PA remains obscure. A more recent report by Kimura et al. (J. Biochem. 2022; 171:429-441) solved the crystal structure of FbTam41, a functional ortholog from a Firmicutes bacterium, with CTP-Mg2+, successfully providing a detailed molecular view of CDP-DAG synthesis. In this commentary, our current understanding of Tam41-mediated reaction is discussed.
PubMed: 38896689
DOI: 10.1093/jb/mvae046 -
Protein Science : a Publication of the... Jul 2024Alzheimer's disease is the fastest-growing neurodegenerative disease that affects over six million Americans. The abnormal aggregation of amyloid β peptide and Tau...
Alzheimer's disease is the fastest-growing neurodegenerative disease that affects over six million Americans. The abnormal aggregation of amyloid β peptide and Tau protein is the expected molecular cause of the loss of neurons in brains of AD patients. A growing body of evidence indicates that lipids can alter the aggregation rate of amyloid β peptide and modify the toxicity of amyloid β aggregates. However, the role of lipids in Tau aggregation remains unclear. In this study, we utilized a set of biophysical methods to determine the extent to which phospatidylserine (PS) altered the aggregation properties of Tau isoforms with one (1N4R) and two (2N4R) N terminal inserts that enhance the binding of Tau to tubulin. We found that the length and saturation of fatty acids (FAs) in PS altered the aggregation rate of 2N4R isoform, while no changes in the aggregation rate of 1N4R were observed. These results indicate that N terminal inserts play an important role in protein-lipid interactions. We also found that PS could change the toxicity of 1N4R and 2N4R Tau fibrils, as well as alter molecular mechanisms by which these aggregates exert cytotoxicity to neurons. Finally, we found that although Tau fibrils formed in the presence and absence of PS endocytosed by cells, only fibril species that were formed in the presence of PS exert strong impairment of the cell mitochondria.
Topics: tau Proteins; Humans; Phosphatidylserines; Tubulin; Alzheimer Disease; Protein Binding; Neurons; Protein Aggregates; Protein Isoforms
PubMed: 38895991
DOI: 10.1002/pro.5078 -
International Journal of Molecular... Jun 2024Renal ischemia/reperfusion is a serious condition that not only causes acute kidney injury, a severe clinical syndrome with high mortality, but is also an inevitable...
Renal ischemia/reperfusion is a serious condition that not only causes acute kidney injury, a severe clinical syndrome with high mortality, but is also an inevitable part of kidney transplantation or other kidney surgeries. Alterations of oxygen levels during ischemia/reperfusion, namely hypoxia/reoxygenation, disrupt mitochondrial metabolism and induce structural changes that lead to cell death. A signature mitochondrial phospholipid, cardiolipin, with many vital roles in mitochondrial homeostasis, is one of the key players in hypoxia/reoxygenation-induced mitochondrial damage. In this study, we analyze the effect of hypoxia/reoxygenation on human renal proximal tubule epithelial cell (RPTEC) cardiolipins, as well as their metabolism and mitochondrial functions. RPTEC cells were placed in a hypoxic chamber with a 2% oxygen atmosphere for 24 h to induce hypoxia; then, they were replaced back into regular growth conditions for 24 h of reoxygenation. Surprisingly, after 24 h, hypoxia cardiolipin levels substantially increased and remained higher than control levels after 24 h of reoxygenation. This was explained by significantly elevated levels of cardiolipin synthase and lysocardiolipin acyltransferase 1 (LCLAT1) gene expression and protein levels. Meanwhile, hypoxia/reoxygenation decreased ADP-dependent mitochondrial respiration rates and oxidative phosphorylation capacity and increased reactive oxygen species generation. Our findings suggest that hypoxia/reoxygenation induces cardiolipin remodeling in response to reduced mitochondrial oxidative phosphorylation in a way that protects mitochondrial function.
Topics: Humans; Cardiolipins; Mitochondria; Cell Hypoxia; Reactive Oxygen Species; Oxygen; Kidney Tubules, Proximal; Oxidative Phosphorylation; Kidney; Cell Line; Transferases (Other Substituted Phosphate Groups); Membrane Proteins
PubMed: 38892409
DOI: 10.3390/ijms25116223 -
Plants (Basel, Switzerland) May 2024In plant models such as , phosphatidic acid (PA), a key molecule of lipid signaling, was shown not only to be involved in stress responses, but also in plant development...
In plant models such as , phosphatidic acid (PA), a key molecule of lipid signaling, was shown not only to be involved in stress responses, but also in plant development and nutrition. In this article, we highlight lipid signaling existing in crop species. Based on open access databases, we update the list of sequences encoding phospholipases D, phosphoinositide-dependent phospholipases C, and diacylglycerol-kinases, enzymes that lead to the production of PA. We show that structural features of these enzymes from model plants are conserved in equivalent proteins from selected crop species. We then present an in-depth discussion of the structural characteristics of these proteins before focusing on PA binding proteins. For the purpose of this article, we consider RESPIRATORY BURST OXIDASE HOMOLOGUEs (RBOHs), the most documented PA target proteins. Finally, we present pioneering experiments that show, by different approaches such as monitoring of gene expression, use of pharmacological agents, ectopic over-expression of genes, and the creation of silenced mutants, that lipid signaling plays major roles in crop species. Finally, we present major open questions that require attention since we have only a perception of the peak of the iceberg when it comes to the exciting field of phospholipid signaling in plants.
PubMed: 38891340
DOI: 10.3390/plants13111532 -
Nature Communications Jun 2024The transient receptor potential canonical type 3 (TRPC3) channel plays a pivotal role in regulating neuronal excitability in the brain via its constitutive activity....
The transient receptor potential canonical type 3 (TRPC3) channel plays a pivotal role in regulating neuronal excitability in the brain via its constitutive activity. The channel is intricately regulated by lipids and has previously been demonstrated to be positively modulated by PIP. Using molecular dynamics simulations and patch clamp techniques, we reveal that PIP predominantly interacts with TRPC3 at the L3 lipid binding site, located at the intersection of pre-S1 and S1 helices. We demonstrate that PIP sensing involves a multistep mechanism that propagates from L3 to the pore domain via a salt bridge between the TRP helix and S4-S5 linker. Notably, we find that both stimulated and constitutive TRPC3 activity require PIP. These structural insights into the function of TRPC3 are invaluable for understanding the role of the TRPC subfamily in health and disease, in particular for cardiovascular diseases, in which TRPC3 channels play a major role.
Topics: TRPC Cation Channels; Humans; Molecular Dynamics Simulation; Phosphatidylinositol 4,5-Diphosphate; HEK293 Cells; Binding Sites; Animals; Patch-Clamp Techniques; Protein Binding
PubMed: 38890374
DOI: 10.1038/s41467-024-49396-6 -
Alcohol and Alcoholism (Oxford,... May 2024To investigate the association between alcohol consumption registered daily with a digital smartphone-based diary and concentration of phosphatidylethanol (PEth)...
AIMS
To investigate the association between alcohol consumption registered daily with a digital smartphone-based diary and concentration of phosphatidylethanol (PEth) 16:0/18:1 in a population without a known alcohol use disorder (AUD), and evaluate whether prospective registration of alcohol consumption is better than retrospective registration and if the association between alcohol intake and PEth was affected by sex or body mass index (BMI).
METHODS
A total of 41 women and 21 men without AUD-diagnosis registered their alcohol consumption prospectively with a digital diary for 14 days, and retrospectively with the Timeline Followback method in the same time interval. PEth was measured before and after the registration period.
RESULTS
The correlation between alcohol consumption and PEth varied from 0.65 to 0.87. It did not depend significantly on the reporting method, and was not influenced by sex or BMI. Based on the regression coefficient, a reduction of alcohol consumption by two alcohol units (26 g of pure ethanol) per day would lead to a reduction of the PEth concentration of about 0.1 μmol/l, and vice versa.
CONCLUSIONS
There was a good correlation between PEth concentration and alcohol consumption, both when alcohol consumption was reported prospectively and retrospectively. The preferred cut-off for PEth should be adjusted to the level of alcohol consumption considered harmful and a purposeful trade-off between sensitivity and specificity. In order to identify persons with a daily alcohol consumption of more than two or three units of alcohol with a sensitivity of 80% or 90%, we suggest a cut-off of around 0.1 μmol/l.
Topics: Humans; Male; Female; Alcohol Drinking; Smartphone; Adult; Middle Aged; Glycerophospholipids; Retrospective Studies; Healthy Volunteers; Prospective Studies; Young Adult; Body Mass Index; Self Report
PubMed: 38881524
DOI: 10.1093/alcalc/agae040 -
Skin Research and Technology : Official... Jun 2024
Topics: Burns; Platelet Activating Factor; Cell-Derived Microparticles; Humans; Animals; Male; Alcoholic Intoxication; Immune Tolerance
PubMed: 38881182
DOI: 10.1111/srt.13743 -
Biomedicine & Pharmacotherapy =... Jul 2024Myocardial reperfusion injury occurs when blood flow is restored after ischemia, an essential process to salvage ischemic tissue. However, this phenomenon is intricate,... (Review)
Review
Myocardial reperfusion injury occurs when blood flow is restored after ischemia, an essential process to salvage ischemic tissue. However, this phenomenon is intricate, characterized by various harmful effects. Tissue damage in ischemia-reperfusion injury arises from various factors, including the production of reactive oxygen species, the sequestration of proinflammatory immune cells in ischemic tissues, the induction of endoplasmic reticulum stress, and the occurrence of postischemic capillary no-reflow. Secretory phospholipase A2 (sPLA2) plays a crucial role in the eicosanoid pathway by releasing free arachidonic acid from membrane phospholipids' sn-2 position. This liberated arachidonic acid serves as a substrate for various eicosanoid biosynthetic enzymes, including cyclooxygenases, lipoxygenases, and cytochromes P450, ultimately resulting in inflammation and an elevated risk of reperfusion injury. Therefore, the activation of sPLA2 directly correlates with the heightened and accelerated damage observed in myocardial ischemia-reperfusion injury (MIRI). Presently, clinical trials are in progress for medications aimed at sPLA2, presenting promising avenues for intervention. Cardiolipin (CL) plays a crucial role in maintaining mitochondrial function, and its alteration is closely linked to mitochondrial dysfunction observed in MIRI. This paper provides a critical analysis of CL modifications concerning mitochondrial dysfunction in MIRI, along with its associated molecular mechanisms. Additionally, it delves into various pharmacological approaches to prevent or alleviate MIRI, whether by directly targeting mitochondrial CL or through indirect means.
Topics: Humans; Myocardial Reperfusion Injury; Animals; Cardiolipins; Phospholipases A2, Secretory
PubMed: 38878685
DOI: 10.1016/j.biopha.2024.116936 -
Journal of Hazardous Materials Aug 2024Exposure to ozone (O) has been associated with cardiovascular outcomes in humans, yet the underlying mechanisms of the adverse effect remain poorly understood. We aimed...
Exposure to ozone (O) has been associated with cardiovascular outcomes in humans, yet the underlying mechanisms of the adverse effect remain poorly understood. We aimed to investigate the association between O exposure and glycerophospholipid metabolism in healthy young adults. We quantified plasma concentrations of phosphatidylcholines (PCs) and lysophosphatidylcholines (lysoPCs) using a UPLC-MS/MS system. Time-weighted personal exposures were calculated to O and co-pollutants over 4 time windows, and we employed orthogonal partial least squares discriminant analysis to discern differences in lipids profiles between high and low O exposure. Linear mixed-effects models and mediation analysis were utilized to estimate the associations between O exposure, lipids, and cardiovascular physiology indicators. Forty-three healthy adults were included in this study, and the mean (SD) time-weighted personal exposures to O was 9.08 (4.06) ppb. With shorter exposure durations, O increases were associated with increasing PC and lysoPC levels; whereas at longer exposure times, the opposite relationship was shown. Furthermore, two specific lipids, namely lysoPC a C26:0 and lysoPC a C17:0, showed significantly positive mediating effects on associations of long-term O exposure with pulse wave velocity and systolic blood pressure, respectively. Alterations in specific lipids may underlie the cardiovascular effects of O exposure.
Topics: Humans; Ozone; Male; Female; Adult; Air Pollutants; Young Adult; Lysophosphatidylcholines; Glycerophospholipids; Environmental Exposure; Phosphatidylcholines
PubMed: 38876019
DOI: 10.1016/j.jhazmat.2024.134870