Albumins Research Articles

Cereal processing by-products and wastewater for sustainable protein extraction.

Cereal processing by-products and wastewater for sustainable protein extraction.

Any1 is a phospholipid scramblase involved in endosome biogenesis.

Endosomes are central organelles in the recycling and degradation of receptors and membrane proteins. Once endocytosed, such proteins are sorted at endosomes into intraluminal vesicles (ILVs). The resulting multivesicular bodies (MVBs) then fuse with the lysosomes, leading to the degradation of ILVs and recycling of the resulting monomers. However, the biogenesis of MVBs requires a constant lipid supply for efficient ILV formation. An ER-endosome membrane contact site has been suggested to play a critical role in MVB biogenesis. Here, we identify Any1 as a novel phospholipid scramblase, which functions with the lipid transfer protein Vps13 in MVB biogenesis. We uncover that Any1 cycles between the early endosomes and the Golgi and colocalizes with Vps13, possibly at a here-discovered potential contact site between lipid droplets (LDs) and endosomes. Strikingly, both Any1 and Vps13 are required for MVB formation, presumably to couple lipid flux with membrane homeostasis during ILV formation and endosome maturation.

Pollen Food Allergy Syndrome in Southern European Adults: Patterns and Insights

Oral Allergy Syndrome (OAS) is an allergic reaction that occurs upon contact of the mouth and throat with food, leading to symptoms primarily affecting the oral mucosa. In patients with allergic rhinitis, OAS may develop due to cross-reactivity between the pollen allergens responsible for allergic rhinitis, and specific plant-derived foods. This particular type of OAS is known as Pollen Food Allergy Syndrome (PFAS). The difference in prevalence of PFAS across different regions of the world is attributed to various factors, including environmental exposure and dietary habits. Southern Europe’s temperate climate favors the blooming of many allergenic plants, making respiratory allergies and PFAS significant public health concerns. There is a regional variation in pollen in Southern Europe, contributing to differences in the presence of panallergens—such as profilins, pathogenesis-related class 10 (PR-10) proteins and lipid transfer proteins (LTPs)—which mediate PFAS. In order to examine the epidemiology, pathogenesis, and diagnostic approaches of OAS and PFAS, focusing on their prevalence and impact in Southern European adults, a narrative review was performed. Data from Portugal, Spain, France, Italy, Albania, Greece, and Türkiye were retrieved. The main outcome of this review was that the frequency of PFAS varies across studies, not only between countries but also within the same country, due to vegetation variability across regions as well as methodological differences and the year of study. However, despite these differences, PFAS emerges as a common issue in Southern Europe, underscoring the need for effective diagnosis and management.

Characterising Lipid Transfer Protein Allergy in UK Adults.

Characterising Lipid Transfer Protein Allergy in UK Adults.

VAPA mediates lipid exchange between Leishmania amazonensis and host macrophages.

Leishmania is a vacuolar pathogen that replicates within parasitophorous vacuoles inside host phagocytes. To promote its replication, Leishmania relies on a panoply of strategies to acquire macromolecules such as lipids from host macrophages. In this study, we have evaluated the role of VAPA, an endoplasmic reticulum-resident membrane protein involved in inter-organellar lipid transport, in macrophages infected with L. amazonensis. Following infection of bone marrow-derived macrophages with metacyclic L. amazonensis promastigotes, we observed that VAPA gradually associates with communal parasitophorous vacuoles. Knockdown of VAPA prevented the replication of L. amazonensis, which was accompanied by an impaired parasitophorous vacuole expansion. Using fluorescent ceramide, we established that VAPA is required for the transport of sphingolipids to the parasitophorous vacuoles and for its acquisition by L. amazonensis amastigotes. Proximity-ligation assays revealed that L. amazonensis hijacks VAPA by disrupting its interactions with the host cell lipid transfer proteins CERT and ORP1L. Finally, we found that VAPA is essential for the transfer of the Leishmania virulence glycolipid lipophosphoglycan from the parasitophorous vacuoles to the host cell endoplasmic reticulum. We propose that VAPA contributes to the ability of L. amazonensis to colonize macrophages by mediating bi-directional transfer of lipids essential for parasite replication and virulence between the parasitophorous vacuoles and the host cell endoplasmic reticulum.

Neurodegenerative and Neurodevelopmental Roles for Bulk Lipid Transporters VPS13A and BLTP2.

Bridge-like lipid transfer proteins (BLTPs) mediate bulk lipid transport at membrane contact sites. Mutations in BLTPs are linked to both early-onset neurodevelopmental and later-onset neurodegenerative diseases, including movement disorders. The tissue specificity and temporal requirements of BLTPs in disease pathogenesis remain poorly understood. The objective of this study was to determine tissue-specific and aging-dependent roles for VPS13A and BLTP2 using Drosophila models. We generated tissue-specific knockdowns of the VPS13A ortholog (Vps13) and the BLTP2 ortholog (hobbit) in neurons and muscles of Drosophila. We analyzed age-dependent locomotor behavior, neurodegeneration, and synapse development and function. Neuron-specific loss of the VPS13A ortholog caused neurodegeneration followed by aging-dependent movement deficits and reduced lifespan, whereas muscle-specific loss affected only lifespan. In contrast, neuronal loss of the BLTP2 ortholog resulted in severe early-onset locomotor defects without neurodegeneration, whereas muscle loss impaired synaptogenesis and neurotransmission at the neuromuscular junction. VPS13A maintains neuronal survival, whereas BLTP2 orchestrates synaptic development. The phenotypic specificity of BLTP function provides mechanistic insights into distinct disease trajectories for BLTP-associated disorders. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

PDZD8 promotes autophagy at ER-lysosome membrane contact sites to regulate activity-dependent synaptic growth.

PDZD8 promotes autophagy at ER-lysosome membrane contact sites to regulate activity-dependent synaptic growth.

S-palmitoylation modulates ATG2-dependent non-vesicular lipid transport during starvation-induced autophagy.

Lipid transfer proteins mediate the non-vesicular transport of lipids at membrane contact sites to regulate the lipid composition of organelle membranes. Despite significant recent advances in our understanding of the structural basis for lipid transfer, its functional regulation remains unclear. In this study, we report that S-palmitoylation modulates the cellular function of ATG2, a rod-like lipid transfer protein responsible for transporting phospholipids from the endoplasmic reticulum (ER) to phagophores during autophagosome formation. During starvation-induced autophagy, ATG2A undergoes depalmitoylation as the balance between ZDHHC11-mediated palmitoylation and APT1-mediated depalmitoylation. Inhibition of ATG2A depalmitoylation leads to impaired autophagosome formation and disrupted autophagic flux. Further, in cell and in vitro analyses demonstrate that S-palmitoylation at the C-terminus of ATG2A anchors the C-terminus to the ER. Depalmitoylation detaches the C-terminus from the ER membrane, enabling it to interact with phagophores and promoting their growth. These findings elucidate a S-palmitoylation-dependent regulatory mechanism of cellular ATG2, which may represent a broad regulatory strategy for lipid transport mediated by bridge-like transporters within cells.

Internalization of affinity tags enables the purification of secreted Chlamydomonas proteins

There is great interest in establishing microalgae as new platforms for the sustainable production of high-value products such as recombinant proteins. Many human therapeutic proteins must be glycosylated, which requires their passage through the secretory pathway into the culture medium. While the low complexity of proteins in the culture medium should facilitate affinity purification of secreted recombinant proteins, this has proven challenging for proteins secreted by the unicellular green alga Chlamydomonas reinhardtii. In Leishmania tarentulae, we observed that C-terminally exposed affinity tags are frequently truncated, presumably due to proteolytic activity. We wondered whether this might also occur in Chlamydomonas and contribute to the difficulties in affinity purification of secreted proteins in this alga. Using the methionine-rich 2S albumin from Bertholletia excelsa and the ectodomain of the SARS-CoV-2 spike protein produced and secreted in Chlamydomonas, we demonstrate that they can be efficiently affinity-purified from the culture medium by Ni-NTA chromatography when the 8xHis affinity tag is internalized. This finding represents an important step towards further development of Chlamydomonas as a host for the sustainable production of high-value recombinant proteins.

Lipid Dynamics at Membrane Contact Sites.

In eukaryotes, lipid building blocks for cellular membranes are made largely in the endoplasmic reticulum and then redistributed to other organelles. Lipids are transported between organelles by vesicular trafficking or else by proteins located primarily at sites where different organelles are closely apposed. Here we discuss transport at organelle contact sites mediated by shuttle-like proteins that carry single lipids between membranes to fine-tune their composition and by the more recently discovered bridge-like proteins that tether two organelles and provide a path for bulk lipid movement. Protein-mediated lipid transport is assisted by integral membrane proteins that have roles in (a) lowering the energy barrier for lipid transfer between the membrane and the lipid transfer protein, a key parameter determining the transfer rate, and (b) scrambling lipids to counteract the bilayer asymmetry that would result from such transfer. Advances in this field are shedding new light on a variety of physiological mechanisms.

Diagnosis and Management of Lipid Transfer Protein Allergy-A BSACI Clinical Practice Statement.

Although the most prevalent plant food allergy in the United Kingdom (UK) is pollen food syndrome (PFS), there is increasing evidence that reactions to plant foods could also be due to sensitisation to Lipid Transfer Proteins (LTP). These proteins, highly resistant to heat and processing, are present in raw, cooked and processed plant foods and often provoke moderate to severe symptoms. LTP allergy is common in Mediterranean countries, but there is a lack of epidemiological data from Northern Europe, although small case series have been published characterising LTP allergy in both England and Scotland. To gather further information and aid the development of a clinical practice statement on LTP allergy, a survey was conducted by the British Society of Allergy and Clinical Immunology (BSACI). The results confirmed that LTP allergy is being diagnosed in both children and adults in all areas of the UK. The survey results, along with published UK data, confirm that tree nuts, peanuts, apples, stone fruits, tomatoes and processed foods, such as pizza or curry, are common food triggers. Anaphylactic reactions are not uncommon and are often facilitated by the presence of co-factors such as exercise or alcohol. Unlike LTP allergy in Spain and Italy, UK individuals are also more likely to be sensitised to birch and grass pollen, but this does not appear to reduce the severity of the condition. Diagnosis can be complex; a positive test to individual LTP allergens can only be confirmatory of a diagnosis of LTP allergy when accompanied by a typical clinical history. Management can be difficult, and individualised advice is vital to avoid the exclusion of multiple foods and minimise the likelihood of co-factors. Given the diverse range of foods, co-factor involvement and highly idiosyncratic nature of LTP allergy, the need for adrenaline autoinjectors should always be considered.

IgE-mediated lipid transfer protein allergy in children.

Lipid Transfer Protein (LTP) allergy, traditionally more prevalent in adults from Southern Europe, is increasingly recognized in pediatric populations worldwide. This review explores the epidemiology, pathogenesis, clinical manifestations, diagnosis, and management of LTP allergy in children. LTP allergy can present with severe systemic symptoms both in children and adults; in children-only studies, anaphylaxis is reported in up to half of the patients. Moreover, children often display polysensitization to multiple plant-based foods. The prevalence of LTP allergy among children remains under-researched, contributing to diagnostic and clinical practice variability. Key allergenic sources involved include peach (Pru p 3) and other Rosaceae fruits, as well as tree nuts, with cofactors such as physical activity frequently triggering or exacerbating reactions. Advancements in understanding natural tolerance and targeted therapies, along with expanding LTP immunotherapy, offer promising directions for improving the management of this challenging condition in pediatric patients.

Comprehensive analysis of the LTPG gene family in willow: Identification, expression profiling, and stress response.

Comprehensive analysis of the LTPG gene family in willow: Identification, expression profiling, and stress response.

Insights from lipidomics into the terminal maturation of circulating human reticulocytes

In the age of “omics”, lipidomics of erythropoiesis is still missing. How reticulocytes mature in the circulation into functional erythrocytes is also largely unknown. We have isolated here two populations of human circulating reticulocytes at different levels of maturation, and three subpopulations of erythrocytes of different age, and characterized the evolution of their lipidome. (Sphingomyelin+cholesterol) and partly phosphatidylethanolamine increase relative to total lipids, whereas phosphatidylcholine and phosphatidylserine decrease from immature reticulocytes to mature erythrocytes, at the same time as the surface area per cell decreases. The relative amounts of more than 70 phospholipid subclasses, based on the number of carbon atoms (12–24) and of double bonds (0–6) in the fatty acids linked to the phospholipid, also change in the process. As reticulocytes and erythrocytes cannot perform de-novo phospholipid synthesis, lipid remodeling likely requires selective removal of phospholipids from the membrane or their exchange with plasma or both, with the possible involvement of lipid transfer proteins such as VPS13A, which is expressed in reticulocytes and erythrocytes. These findings not only shed light on fundamental aspects of red blood cell physiology and erythropoiesis but also raise intriguing questions surrounding protein-lipid interactions, membrane architecture, and lipid trafficking mechanisms.

Hoi1 targets the yeast BLTP2 protein to ER-PM contact sites to regulate lipid homeostasis.

Membrane contact sites between organelles are important for maintaining cellular lipid homeostasis. Members of the recently identified family of bridge-like lipid transfer proteins (BLTPs) span opposing membranes at these contact sites to enable the rapid transfer of bulk lipids between organelles. While the VPS13 and ATG2 family members use organelle-specific adaptors for membrane targeting, the mechanisms that regulate other bridge-like transporters remain unknown. Here, we identify the conserved protein Ybl086c, which we name Hoi1 (Hob interactor 1), as an adaptor that targets the yeast BLTP2-like proteins Fmp27/Hob1 and Hob2 to ER-PM contact sites. Two separate Hoi1 domains interface with alpha-helical projections that decorate the central hydrophobic channel on Fmp27, and loss of these interactions disrupts cellular sterol homeostasis. The mutant phenotypes of BLTP2 and HOI1 orthologs indicate these proteins act in a shared pathway in worms and flies. Together, this suggests that Hoi1-mediated recruitment of BLTP2-like proteins represents an evolutionarily conserved mechanism for regulating lipid transport at membrane contact sites.

Sunflower (Helianthus annuus) Seed Allergy.

Sunflower seed is one of the most common edible seeds. Its consumption is growing. Cases of sunflower seed allergy have been reported since the 1970s. However, there are few data on the prevalence and clinical manifestations of sunflower seed allergy. To improve our understanding of sunflower seed allergy. We evaluated the clinical and immunological features of patients with sunflower seed allergy diagnosed in the allergy department of a tertiary hospital in Madrid over a 5-year period. Forty-seven patients reported adverse reactions after ingestion of sunflower seed and were sensitized specifically to sunflower seed, as determined by skin prick test (median, 8 mm) or specific IgE (median, 1.10 kUA/L). Most reactions were adult-onset and were preceded by a history of atopy and other food allergies, predominantly to peach, peanut, and nuts. The clinical presentation of sunflower seed allergy ranged from mild to severe, with many patients experiencing severe reactions, in which epinephrine was underused. Repeated exposures to sunflower seed in the same patient showed severity of symptoms to vary. Levels of sunflower seed IgE were strongly correlated with levels of IgE to nonspecific lipid transfer proteins, while the severity of the reactions did not differ significantly according to sensitization to the proteins. Our findings reveal variability in the clinical presentations of sunflower seed allergy on repeated exposures and underuse of epinephrine in anaphylaxis. We highlight the importance of strict avoidance of sunflower seed and accurate prescription and administration of epinephrine in allergic patients.

VPS13D mutations affect mitochondrial homeostasis and locomotion in Caenorhabditis elegans.

Mitochondria control cellular metabolism, serve as hubs for signaling and organelle communication, and are important for the health and survival of cells. VPS13D encodes a cytoplasmic lipid transfer protein that regulates mitochondrial morphology, mitochondria and endoplasmic reticulum (ER) contact, quality control of mitochondria. VPS13D mutations have been reported in patients displaying ataxic and spastic gait disorders with variable age of onset. Here we used CRISPR/Cas9 gene editing to create VPS13D related-spinocerebellar ataxia-4 (SCAR4) missense mutations and C-terminal deletion in VPS13D's orthologue vps-13D in C. elegans. Consistent with SCAR4 patient movement disorders and mitochondrial dysfunction, vps-13D mutant worms exhibit locomotion defects and abnormal mitochondrial morphology. Importantly, animals with a vps-13D deletion or a N3017I missense mutation exhibited an increase in mitochondrial unfolded protein response (UPRmt). The cellular and behavioral changes caused by VPS13D mutations in C. elegans advance the development of animal models that are needed to study SCAR4 pathogenesis.

Lipid Transfer Proteins (LTPs) Partially Purified from Capsicum chinense Jacq. Seeds: Antifungal Properties and α-amylase Inhibitory Activity.

In this study, we identified and partially purified antimicrobial peptides belonging to the family of lipid transfer proteins (LTPs) from Capsicum chinense seeds (UENF 1751 accession). Fractions rich in LTPs were obtained via ion exchange chromatography and subsequently purified via reverse-phase chromatography in an HPLC system. Therefore, two fractions were revealed: C1 (the nonretained fraction) and C2 (the retained fraction in ion-exchange chromatography). Fraction C1 was subjected to reverse-phase chromatography via a C18 column on an HPLC system, and ten fractions were obtained (P1-P10), all of which significantly inhibited the growth of Candida albicans, except for P4 and P9. The viability analysis of the active fractions at a concentration of 100µg.mL-1 against C. albicans revealed that they did not exhibit fungicidal activity but rather exhibited fungistatic activity. The peptide is considered fungicidal when it results in the total loss of viable yeast cells, that is, when it causes the complete death of the fungi. When the substance only inhibits cell growth, but does not eliminate them completely, the effect is classified as fungistatic. Fractions P3, P4, P7, and P10 inhibited Tenebrio molitor larvae α-amylase. The P10 fraction presented protein bands in its electrophoretic profile with a molecular mass between 6.5kDa and 14.2kDa and reacted positively to an antibody produced against a protein from the LTP family bywestern blotting. The results of the analysis of amino acid residues from the P10 fraction revealed similarity between type I LTPs and type II LTPs. The ultrastructural aspects of C. albicans cells exposed to the P10 fraction were evaluated via transmission electron microscopy (TEM), with significant differences in their morphology being evident compared with those of the control. In summary, our results demonstrated the presence of LTPs in C. chinense seeds with inhibitory effects on the growth of yeasts of the genus Candida, which exhibited fungistatic effects and structural changes in C. albicans cells, in addition to exhibiting inhibitory effects on the larval insect T. molitor α-amylase.

Lipid transfer protein VAS inhibits the hypersensitive response via reactive oxygen species signaling in Nicotiana benthamiana.

Lipid transfer proteins (LTPs) are small cysteine-rich soluble proteins that affect flower and seed development, cuticular wax deposition, and biotic and abiotic stress responses. We isolated an LTP-encoding gene homologous to LTPVAS in Nicotiana benthamiana and designated it LTP-VASCULAR TISSUE SIZE (NbLTPVAS). This gene was expressed in seeds, leaves, roots, and stems. Additionally, NbLTPVAS expression was induced by hypersensitive response (HR)-inducing agents. Cell death was accelerated and the phytopathogenic bacterial population decreased significantly in NbLTPVAS-silenced plants infected with the incompatible Ralstonia solanacearum strain 8107. The expression of HR marker gene hin1 in NbLTPVAS-silenced plants was markedly induced by R. solanacearum 8107, indicative of the acceleration of HR. HR cell death in NbLTPVAS-silenced plants was also promoted by the Agrobacterium-mediated expression of HR-inducing proteins including INF1, AvrA, and PopP1. Excessive production of reactive oxygen species (ROS) was detected in NbLTPVAS-silenced plants. The expression of NbrbohB (encoding a ROS-generating enzyme) also increased in NbLTPVAS-silenced plants, but the expression of the antioxidant enzyme-encoding genes NbSOD and NbAPX decreased. The silencing of both NbLTPVAS and NbrbohB adversely affected HR induction. Moreover, NbLTPVAS was secreted into the intercellular washing fluid. The transient expression of the full-length NbLTPVAS induced the expression of antioxidant genes, attenuated ROS production, and suppressed the induction of HR cell death. This is the first functional analysis of LTPVAS in plant-microbe interactions. Our study provides novel insights into the role of NbLTPVAS as a negative regulator of HR via ROS homeostasis in N. benthamiana.

Multiple interactions mediate the localization of BLTP2 at ER-PM contacts to control plasma membrane dynamics.

BLTP2/KIAA0100, a bridge-like lipid transfer protein, was reported to localize at contacts of the endoplasmic reticulum (ER) with either the plasma membrane (PM) or recycling tubular endosomes depending on the cell type. Our findings suggest that mediating bulk lipid transport between the ER and the PM is a key function of this protein as BLTP2 tethers the ER to tubular endosomes only after they become continuous with the PM and that it also tethers the ER to macropinosomes in the process of fusing with the PM. We further identify interactions underlying binding of BLTP2 to the PM, including phosphoinositides, the adaptor proteins FAM102A and FAM102B, and also N-BAR domain proteins at membrane-connected tubules. The absence of BLTP2 results in the accumulation of intracellular vacuoles, many of which are connected to the plasma membrane, pointing to a role of the lipid transport function of BLTP2 in the control of PM dynamics.