Biology subjects

Petkevicius, K.

Publications and source records attributed to Petkevicius, K..

7 recordsLinked to original sources

bioRxiv2026

CLN6 is a glycerophosphoglycerol epimerase in bis(monoacylglycero)phosphate biosynthesis

Lysosomal catabolism depends on bis(monoacylglycero)phosphate (BMP), a phospholipid with atypical S,S stereochemistry of unknown biosynthetic origin. CLN8 and CLN5 catalyze sequential acylation steps in BMP synthesis, and their loss of function causes Batten disease, a group of inherited neurodegenerative lysosomal storage disorders. Here we identify CLN6, a biochemically uncharacterized endoplasmic reticulum protein whose loss also causes Batten disease, as the calcium-dependent glycerophosphoglycerol epimerase that establishes BMP stereochemistry upstream of CLN8. CLN6 deficiency depletes BMP in cells, mice, and patient lysosomes, and reduces lysosomal hydrolase levels. BMP-precursor supplementation bypasses CLN6, restores BMP and increases hydrolase abundance in CLN6-deficient cells and mice. These findings place three Batten disease proteins in a single biosynthetic pathway and reveal BMP deficiency as a reversible cause of disrupted lysosomal hydrolase homeostasis.

biochemistry↗

bioRxiv2026

Molecular insights into ATP synthase c-ring accumulation in BMP-deficient lysosomes in Batten disease

Bis(monoacylglycero)phosphate (BMP) is a signature lysosomal phospholipid that supports the catabolic functions of the lysosome. We recently demonstrated that BMP deficiency is associated with a variant of Batten disease, a neurodegenerative lysosomal storage disorder. This observation led us to investigate how BMP deficiency contributes to the previously reported accumulation of the ATP synthase c-ring in the lysosomes of Batten disease patients and preclinical models. The c-ring is an inner mitochondrial membrane (IMM) protein complex that interacts with cardiolipin, a mitochondrial phospholipid that shares structural features with BMP. Based on this, we hypothesised that BMP may perform an analogous function to cardiolipin in lysosomes. Specifically, we proposed that BMP preferentially interacts with the c-ring, dispersing it within lysosomal membranes and facilitating its degradation. To test this hypothesis, we conducted all-atom molecular dynamics simulations to examine the interactions of various BMP variants with the c-ring of human ATP synthase under different membrane conditions. We observed leaflet-specific preferential interactions of BMP with the protein interface. Replacement of BMP with anionic POPG lipids resulted in a lower binding affinity to the c-ring, indicating the importance of BMPs unique structure with respect to protein binding. Furthermore, BMP enrichment was enhanced when using the physiologically relevant di-22:6 BMP variant in membranes containing polyunsaturated lipids and cholesterol. Overall, our study suggests that BMP promotes lysosomal c-ring degradation via c-ring co-localisation, whereas BMP deficiency in Batten disease drives c-ring accumulation. Significance statementBatten disease comprises a group of neurodegenerative lysosomal storage disorders that primarily affects infants and children. Several recently identified disease genes are linked to the biosynthesis of lipid bis(monoacylglycero)phosphate (BMP), a lysosomal lipid required for normal lysosome function. However, how BMP deficiency contributes to disease pathology remains poorly understood. Here, we investigate the relationship between BMP deficiency and lysosomal accumulation of the ATP synthase c-ring, a hallmark pathological feature of Batten disease. Using molecular simulations, we show that BMP preferentially interacts with the c-ring, suggesting that BMP deficiency promotes c-ring aggregation within lysosomes. Our study provides a mechanistic starting point for understanding how BMP deficiency disrupts lysosomal function in Batten disease

biophysics↗

bioRxiv2025

CLN8 enables a non-canonical phospholipid synthesis pathway

According to text book knowledge, de novo glycerophospholipid (GPL) synthesis begins with the acylation of glycerol-3-phosphate to form phosphatidic acid, the precursor of all other GPLs. Here we describe an alternative GPL synthesis pathway that starts with the acyl-CoA-dependent acylation of glycerophosphoglycerol (GPG), resulting in the formation of lysophosphatidylglycerol (LPG). The acyltransferase reaction is catalyzed by the Batten disease-associated protein ceroid lipofuscinosis neuronal 8 (CLN8). Tracer studies revealed that CLN8-derived LPG is selectively converted into bis(monoacylglycero)phosphate (BMP), a GPL essential for lysosomal lipid homeostasis, but not into phosphatidylglycerol or cardiolipin. CLN8-knockout cells and mice cannot utilize GPG for BMP synthesis, resulting in BMP-deficiency and excess accumulation of phospholipids in lysosomes. The lipid synthesis pathway described herein is relevant for understanding lysosomal lipid metabolism and the pathogenesis of neurodegenerative diseases. BMP-deficiency may contribute to or even underlie lysosomal cargo accumulation in certain forms of Batten disease and other lysosomal storage disorders.

biochemistry↗

bioRxiv2025

Stereospecific GPG acylation by CLN8 drives BMP biosynthesis and its loss leads to Batten disease

Loss-of-function mutations in the endoplasmic reticulum membrane protein CLN8 cause Batten disease, a neurodegenerative lysosomal storage disorder1. Together with the lysosomal enzyme CLN5, CLN8 mediates the biosynthesis of bis(monoacylglycero)phosphate (BMP), a phospholipid essential for lysosomal function and distinguished by its unique S,S stereochemistry2,3. However, the role of CLN8 in BMP synthesis has remained unclear. Here we establish that CLN8 is a glycerophosphoglycerol (GPG) acyltransferase that catalyses the stereospecific acylation of S,S-GPG to produce S,S-lysophosphatidylglycerol (LPG), the CLN5 substrate in BMP synthesis. Using cryo-electron microscopy, we resolve structures of the CLN8 homodimer in apo and substrate-bound states at 2.7 [A] resolution, revealing the active site architecture and a ping-pong acyl transfer mechanism. Batten disease-causing missense mutations impair CLN8 enzymatic activity in vitro and reduce BMP levels in a Cln8R24G knock- in mouse, whereas the Cln8mnd mouse frameshift mutation causes complete loss of BMP in vivo. Exogenous S,S-LPG, but not the R,S stereoisomer, restored BMP synthesis in CLN8- deficient cells and mice, and improved neurological phenotypes in cln8 mutant zebrafish. Together, these findings define the enzymatic function of CLN8, elucidate the biochemical basis of CLN8 Batten disease, and establish a proof-of-concept for treating it through stereospecific BMP precursor supplementation.

biochemistry↗

bioRxiv2021

Sphingosine 1-Phosphate Mediates Adiponectin Receptor Signaling Essential For Lipid Homeostasis And Embryogenesis

Cells and organisms require proper membrane composition to function and develop. Phospholipids are the major component of membranes and are primarily acquired through the diet. Given great variability in diet composition, cells must be able to deploy mechanisms that correct deviations from optimal membrane composition and properties. Here, using lipidomics and unbiased proteomics, we found that the embryonic lethality in mice lacking the fluidity regulators Adiponectin Receptors 1 and 2 (AdipoR1/2) is associated with aberrant high saturation of the membrane phospholipids. Using mouse embryonic fibroblasts (MEFs) derived from AdipoR1/2-KO embryos, human cell lines and the model organism C. elegans we found that, mechanistically, AdipoR1/2-derived sphingosine 1-phosphate (S1P) signals in parallel through S1PR3-SREBP1 and PPAR{gamma} to sustain the expression of the fatty acid desaturase SCD and maintain membrane properties. Thus, our work identifies an evolutionary conserved pathway by which cells and organism achieve membrane homeostasis and adapt to a variable environment.

cell biology↗

bioRxiv2020

Production of moth sex pheromones for pest control by yeast fermentation

The use of insect sex pheromones is an alternative technology for pest control in agriculture and forestry, which, in contrast to insecticides, does not have adverse effects on human health or environment and is efficient also against insecticide-resistant insect populations.1,2 Due to the high cost of chemically synthesized pheromones, mating disruption applications are currently primarily targeting higher value crops, such as fruits.3 Here we demonstrate a biotechnological method for the production of pheromones of economically important moth pests using engineered yeast cell factories. Biosynthetic pathways towards several pheromones or their precursors were reconstructed in the oleaginous yeast Yarrowia lipolytica, which was further metabolically engineered for improved pheromone biosynthesis by decreasing fatty alcohol degradation and downregulating storage lipid accumulation. The sex pheromone of the cotton bollworm Helicoverpa armigera was produced by oxidation of fermented fatty alcohols into corresponding aldehydes. The resulting pheromone was just as efficient and specific for trapping of H. armigera male moths in cotton fields in Greece as a synthetic pheromone mixture. We further demonstrated the production of the main pheromone component of the fall armyworm Spodoptera frugiperda. Our work describes a biotech platform for the production of commercially relevant titres of moth pheromones for pest control by yeast fermentation. Significance statementAgriculture largely relies on insecticides and genetically modified crops for pest control, however alternative solutions are required due to emerging resistance, toxicity and regulatory issues, and consumer preferences. Mating disruption with sex pheromones that act by preventing insect reproduction is considered the most promising and scalable alternative to insecticides. This method is highly efficient and safe for human health and environment. The likelihood of insect resistance development is very low and can be handled by adjusting the pheromone composition. The high cost of chemically synthesized pheromones is the major barrier for the wider adoption of pheromones. A novel method based on yeast fermentation enables the production of insect sex pheromones as a lower cost from renewable feedstocks.

bioengineering↗

bioRxiv2019

Accelerated phosphatidylcholine turnover in macrophages promotes adipose tissue inflammation in obesity

White adipose tissue (WAT) inflammation contributes to the development of insulin resistance in obesity. While the role of adipose tissue macrophage (ATM) pro-inflammatory signalling in the development of insulin resistance has been established, it is less clear how WAT inflammation is initiated. Here, we show that ATMs from obese mice and humans exhibit markers of increased de novo phosphatidylcholine (PC) biosynthesis rate. Macrophage-specific knockout of phosphocholine-cytidylyltransferase A (CCT), the rate-limiting enzyme of de novo PC biosynthesis pathway, alleviated obesity-induced WAT inflammation and insulin resistance. Mechanistically, CCT-deficient macrophages showed reduced ER stress and inflammation in response to palmitate. Surprisingly, this was not due to lower exogenous palmitate incorporation into cellular PCs. Instead, CCT-null macrophages had lower PC turnover, leading to elevated membrane polyunsaturated fatty acids that negated the pro-inflammatory effects of palmitate. Our results reveal a link between obesity-associated increase in PC synthesis, accelerated PC turnover and pro-inflammatory activation of ATMs.

cell biology↗