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Scientific Reports Apr 2024Evolution shapes protein sequences for their functions. Here, we studied the moonlighting functions of the N-linked sequon NXS/T, where X is not P, in human...
Evolution shapes protein sequences for their functions. Here, we studied the moonlighting functions of the N-linked sequon NXS/T, where X is not P, in human nucleocytosolic proteins. By comparing membrane and secreted proteins in which sequons are well known for N-glycosylation, we discovered that cyto-sequons can participate in nucleic acid binding, particularly in zinc finger proteins. Our global studies further discovered that sequon occurrence is largely proportional to protein length. The contribution of sequons to protein functions, including both N-glycosylation and nucleic acid binding, can be regulated through their density as well as the biased usage between NXS and NXT. In proteins where other PTMs or structural features are rich, such as phosphorylation, transmembrane ɑ-helices, and disulfide bridges, sequon occurrence is scarce. The information acquired here should help understand the relationship between protein sequence and function and assist future protein design and engineering.
Topics: Humans; Proteins; Glycosylation; Amino Acid Sequence; Phosphorylation; Nucleic Acids
PubMed: 38565583
DOI: 10.1038/s41598-024-57334-1 -
BioEssays : News and Reviews in... Sep 2023The type III secretion system (T3SS) is a specialized nanomachine that enables bacteria to secrete proteins in a specific order and directly deliver a specific set of... (Review)
Review
The type III secretion system (T3SS) is a specialized nanomachine that enables bacteria to secrete proteins in a specific order and directly deliver a specific set of them, collectively known as effectors, into eukaryotic organisms. The core structure of the T3SS is a syringe-like apparatus composed of multiple building blocks, including both membrane-associated and soluble proteins. The cytosolic components organize together in a chamber-like structure known as the sorting platform (SP), responsible for recruiting, sorting, and initiating the substrates destined to engage this secretion pathway. In this article, we provide an overview of recent findings on the SP's structure and function, with a particular focus on its assembly pathway. Furthermore, we discuss the molecular mechanisms behind the recruitment and hierarchical sorting of substrates by this cytosolic complex. Overall, the T3SS is a highly specialized and complex system that requires precise coordination to function properly. A deeper understanding of how the SP orchestrates T3S could enhance our comprehension of this complex nanomachine, which is central to the host-pathogen interface, and could aid in the development of novel strategies to fight bacterial infections.
Topics: Bacterial Proteins; Secretory Pathway; Protein Transport; Type III Secretion Systems; Cytosol
PubMed: 37329195
DOI: 10.1002/bies.202300078 -
Journal of Proteome Research Sep 2023Cerebrospinal fluid (CSF) is an essential matrix for the discovery of neurological disease biomarkers. However, the high dynamic range of protein concentrations in CSF...
Cerebrospinal fluid (CSF) is an essential matrix for the discovery of neurological disease biomarkers. However, the high dynamic range of protein concentrations in CSF hinders the detection of the least abundant protein biomarkers by untargeted mass spectrometry. It is thus beneficial to gain a deeper understanding of the secretion processes within the brain. Here, we aim to explore if and how the secretion of brain proteins to the CSF can be predicted. By combining a curated CSF proteome and the brain elevated proteome of the Human Protein Atlas, brain proteins were classified as CSF or non-CSF secreted. A machine learning model was trained on a range of sequence-based features to differentiate between CSF and non-CSF groups and effectively predict the brain origin of proteins. The classification model achieves an area under the curve of 0.89 if using high confidence CSF proteins. The most important prediction features include the subcellular localization, signal peptides, and transmembrane regions. The classifier generalized well to the larger brain detected proteome and is able to correctly predict novel CSF proteins identified by affinity proteomics. In addition to elucidating the underlying mechanisms of protein secretion, the trained classification model can support biomarker candidate selection.
Topics: Humans; Proteome; Brain; Protein Transport; Biological Transport; Biomedical Research; Cerebrospinal Fluid Proteins
PubMed: 37606934
DOI: 10.1021/acs.jproteome.3c00366 -
Molecular Biology Reports Sep 2023Cutaneous aging is an inevitable biological process that develops over time due to cumulative cellular and molecular changes caused by exposure to intrinsic... (Review)
Review
PURPOSE
Cutaneous aging is an inevitable biological process that develops over time due to cumulative cellular and molecular changes caused by exposure to intrinsic (chronological aging) and extrinsic (photo-aging) factors on the skin. Skin aging is characterized by a decline in the body's capability to sustain senescence, dermal cell apoptosis, and homeostasis. Stem cell secretions (secretome) are defined as the total set of dynamically overlapping paracrine soluble growth factors, cytokines, chemokines, angiogenic factors, extracellular matrix proteins, and antimicrobial peptides known to be responsible for tissue rejuvenation, regeneration, homeostasis, and immunomodulation.
METHODS
In this review, we summarized the molecular and regulatory mechanism of the secretome in preventing the skin aging process, as well as its capacity in inducing skin rejuvenation. Furthermore, we illustrated secretome efficiency as an anti-aging therapeutic strategy based on in vitro and in vivo published studies.
RESULTS
In all reviewed publications, the secretome has been proven to be the most effective treatment for aged skin, capable of reversing the aging process through the action of cytokines, growth factors, and collagen, which are its primary components. The reported mechanism of action involves modulating the signaling pathways of aging and replenishing the skin with collagen, fibronectin, and elastin, ultimately resulting in skin renewal and rejuvenation.
CONCLUSION
In conclusion, compared to available treatments, the secretome shows great promise as an anti-aging therapy.
Topics: Rejuvenation; Secretome; Intercellular Signaling Peptides and Proteins; Cytokines; Collagen; Stem Cells
PubMed: 37452901
DOI: 10.1007/s11033-023-08622-y -
Cryobiology Dec 2023Currently, the majority of sturgeons are relict fishes of high economic value yet endangered with extinction. Cryopreservation of sperm has great potential in fish... (Review)
Review
Currently, the majority of sturgeons are relict fishes of high economic value yet endangered with extinction. Cryopreservation of sperm has great potential in fish farming and conservation, but the problem of low cryoresistance of sturgeon sperm has not yet been solved. The goal of this work was to review current literature data on the causes of low tolerance of sturgeon sperm to cryodamage. The influence of cryopreservation on the parameters of physiology and metabolism of sturgeon sperm (morphology and fine ultrastructure, mobility and fertilization ability, integrity of the plasma membrane, protein, lipid and metabolite profiles, antioxidant status, DNA damage), as well as on biomarkers of oxidative stress (lipids peroxidation levels and carbonyl derivatives of proteins) is discussed. Since the development of oxidative stress is an important mechanism of sperm cryodamage induction, the review presents the literature on the role of oxygen-derived species in damage of sturgeon reproductive cells caused by cryopreservation. Particular attention is paid to the system of antioxidant protection of sturgeon seminal plasma and spermatozoa, represented by antioxidant enzymes and low molecular weight antioxidants capable of utilizing various reactive forms of oxygen and nitrogen. The review discusses the results of lipidomic and proteomic studies of sturgeon sperm, which made it possible to obtain new data on the lipid composition of cell membranes, to detect proteins involved in the protection of sturgeon spermatozoa from oxidative damage during cryopreservation. This review presents the use of «omics» technology to elucidate the mechanism of cryodamage in sturgeon sperm. Additionally, the review summarizes information on the unique anatomical, morphological, biochemical, and physiological features of sturgeon sperm, which may be associated with low cryoresistance of sturgeon, in order to establish prospects for further research on improving the methods of the conservation of sperm of these threatened species.
Topics: Animals; Male; Antioxidants; Semen; Proteomics; Cryopreservation; Spermatozoa; Oxidative Stress; Fishes; Oxygen; Lipids; Sperm Motility
PubMed: 37848167
DOI: 10.1016/j.cryobiol.2023.104594 -
Cells Oct 2023Impaired iron homeostasis has been proven to be one of the critical contributors to the pathology of Parkinson's disease (PD). Ferritin is considered an intracellular...
Impaired iron homeostasis has been proven to be one of the critical contributors to the pathology of Parkinson's disease (PD). Ferritin is considered an intracellular protein responsible for storing cytosolic iron. Recent studies have found that ferritin can be secreted from cells independent of the classical endoplasmic reticulum-Golgi system. However, the precise mechanisms underlying the secretion of ferritin in the brain were not elucidated. In the present study, we demonstrated that the primary cultured astrocytes do have the ability to secrete ferritin, which is enhanced by iron treatment. Increased ferritin secretion was accompanied by increased protein expression of ferritin response to iron stimulation. Further study showed that iron-induced expression and secretion of ferritin could be inhibited by CQ or 3-MA pretreatment. In addition, the knockdown of transient receptor potential mucolipin 1 (TRPML1) antagonized iron-induced ferritin secretion, accompanied by further increased intracellular protein levels of ferritin. Further study demonstrated that ferritin colocalized with LAMP1 in iron-treated astrocytes. On the contrary, ras-associated protein 27a (Rab27a) knockdown further enhanced iron-induced ferritin secretion and decreased intracellular protein levels of ferritin. Furthermore, we also showed that the secretory autophagy protein tripartite motif containing 16 (TRIM16) and sec22b decreased in iron-treated astrocytes. These results suggested that astrocytes might secrete ferritin via TRPML1-mediated exocytosis. This provides new evidence for the mechanisms underlying the secretion of ferritin in primary cultured astrocytes under a high iron environment.
Topics: Iron; Ferritins; Astrocytes; Biological Transport; Exocytosis
PubMed: 37947597
DOI: 10.3390/cells12212519 -
Bone Research Aug 2023Proper regulation of Wnt signaling is critical for normal bone development and homeostasis. Mutations in several Wnt signaling components, which increase the activity of...
Proper regulation of Wnt signaling is critical for normal bone development and homeostasis. Mutations in several Wnt signaling components, which increase the activity of the pathway in the skeleton, cause high bone mass in human subjects and mouse models. Increased bone mass is often accompanied by severe headaches from increased intracranial pressure, which can lead to fatality and loss of vision or hearing due to the entrapment of cranial nerves. In addition, progressive forehead bossing and mandibular overgrowth occur in almost all subjects. Treatments that would provide symptomatic relief in these subjects are limited. Porcupine-mediated palmitoylation is necessary for Wnt secretion and binding to the frizzled receptor. Chemical inhibition of porcupine is a highly selective method of Wnt signaling inhibition. We treated three different mouse models of high bone mass caused by aberrant Wnt signaling, including homozygosity for loss-of-function in Sost, which models sclerosteosis, and two strains of mice carrying different point mutations in Lrp5 (equivalent to human G171V and A214V), at 3 months of age with porcupine inhibitors for 5-6 weeks. Treatment significantly reduced both trabecular and cortical bone mass in all three models. This demonstrates that porcupine inhibition is potentially therapeutic for symptomatic relief in subjects who suffer from these disorders and further establishes that the continued production of Wnts is necessary for sustaining high bone mass in these models.
Topics: Animals; Humans; Mice; Adaptor Proteins, Signal Transducing; Bodily Secretions; Disease Models, Animal; Gain of Function Mutation; Hyperostosis; Low Density Lipoprotein Receptor-Related Protein-5; Mutation
PubMed: 37612291
DOI: 10.1038/s41413-023-00278-5 -
Cells Sep 2023Lysophosphatidic acid (LPA) signalling is essential for maintaining germ cell viability during mouse spermatogenesis; however, its role in human spermatozoa is unknown....
Lysophosphatidic acid (LPA) signalling is essential for maintaining germ cell viability during mouse spermatogenesis; however, its role in human spermatozoa is unknown. We previously demonstrated that peroxiredoxin 6 (PRDX6) calcium-independent phospholipase A (iPLA) releases lysophospholipids such as LPA or arachidonic acid (AA) and that inhibiting PRDX6 iPLA activity impairs sperm cell viability. The exogenous addition of LPA bypassed the inhibition of PRDX6 iPLA activity and maintained the active phosphoinositide 3-kinase (PI3K)/AKT pathway. Here, we aimed to study PI3K/AKT pathway regulation via LPA signalling and protein kinases in maintaining sperm viability. The localization of LPARs in human spermatozoa was determined using immunocytochemistry, and P-PI3K and P-AKT substrate phosphorylations via immunoblotting. Sperm viability was determined using the hypo-osmotic swelling test. LPAR1, 3, 5 and 6 were located on the sperm plasma membrane. The inhibition of LPAR1-3 with Ki16425 promoted the impairment of sperm viability and decreased the phosphorylation of PI3K AKT substrates. Inhibitors of PKC, receptor-type PTK and PLC impaired sperm viability and the PI3K/AKT pathway. Adding 1-oleoyl-2-acetyl-snglycerol (OAG), a cell-permeable analog of diacylglycerol (DAG), prevented the loss of sperm viability and maintained the phosphorylation of PI3K. In conclusion, human sperm viability is supported by LPAR signalling and regulated by PLC, PKC and RT-PTK by maintaining phosphorylation levels of PI3K and AKT substrates.
Topics: Humans; Male; Lysophospholipids; Peroxiredoxin VI; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Semen
PubMed: 37681929
DOI: 10.3390/cells12172196 -
Pharmaceutical Biology Dec 2023Therapeutic effects of Qiangjing tablets (QJT) on sperm vitality and asthenozoospermia (AZS) have been confirmed. However, the mechanism of action remains unclear.
CONTEXT
Therapeutic effects of Qiangjing tablets (QJT) on sperm vitality and asthenozoospermia (AZS) have been confirmed. However, the mechanism of action remains unclear.
OBJECTIVE
This study investigates the effects of QJT on AZS and the underlying mechanism of action.
MATERIALS AND METHODS
Sixty Sprague-Dawley rats were randomly divided into six groups: Control, ORN (ornidazole; 200 mg/kg), ORN + QJT-low (0.17 g/mL), ORN + QJT-middle (0.33 g/mL), ORN + QJT-high (0.67 g/mL), and ORN + QJT + Radicicol (0.67 g/mL QJT and 20 mg/kg radicicol) groups. Pathological evaluation and analysis of mitophagy were conducted by H&E staining and transmission electron microscopy, respectively. Reactive oxygen species were detected by flow cytometry. Protein expression was determined by Western blotting.
RESULTS
QJT significantly improved ORN-treated sperm motility and kinematic parameters, as well as the pathological symptoms of testicular and epididymal tissues. In particular, QJT mitigated impaired mitochondrial morphology, and increased the PHB, Beclin-1, LC3-II protein, and ROS levels ( < 0.05), and reduced the protein expression levels of LC3-I and p62 ( < 0.05). Mechanistically, QJT antagonized the downregulation of SCF and Parkin protein levels ( < 0.05). Furthermore, QJT significantly increased the protein expressions levels of LKB1, AMPKα, p-AMPKα, ULK1 and p-ULK1 ( < 0.05). The ameliorative effect of QJT on pathological manifestations, mitochondrial morphology, and the expressions of mitophagy and mitochondrial ubiquitination-related proteins was counteracted by radicicol.
DISCUSSION AND CONCLUSIONS
QJT improved AZS mitochondrial ubiquitination and mitophagy mediated by the LKB1/AMPK/ULK1 signaling pathway. Our study provides a theoretical basis for the treatment of AZS and male infertility.
Topics: Animals; Male; Rats; AMP-Activated Protein Kinases; Asthenozoospermia; Autophagy-Related Protein-1 Homolog; Drugs, Chinese Herbal; Intracellular Signaling Peptides and Proteins; Mitophagy; Rats, Sprague-Dawley; Semen; Sperm Motility; Tablets; Ubiquitination
PubMed: 36655371
DOI: 10.1080/13880209.2023.2168021 -
Current Biology : CB Jul 2023Fertilization is a fundamental process in sexual reproduction during which gametes fuse to combine their genetic material and start the next generation in their life...
Fertilization is a fundamental process in sexual reproduction during which gametes fuse to combine their genetic material and start the next generation in their life cycle. Fertilization involves species-specific recognition, adhesion, and fusion between the gametes. In mammals and other model species, some proteins are known to be required for gamete interactions and have been validated with loss-of-function fertility phenotypes. Yet, the molecular basis of sperm-egg interaction is not well understood. In a forward genetic screen for fertility mutants in Caenorhabditis elegans, we identified spe-51. Mutant worms make sperm that are unable to fertilize the oocyte but otherwise normal by all available measurements. The spe-51 gene encodes a secreted protein that includes an immunoglobulin (Ig)-like domain and a hydrophobic sequence of amino acids. The SPE-51 protein acts cell autonomously and localizes to the surface of the spermatozoa. We further show that the gene product of the mammalian sperm function gene Sof1 is likewise secreted. This is the first example of a secreted protein required for the interactions between the sperm and egg with genetic validation for a specific function in fertilization in C. elegans (also see spe-36). This is also the first experimental evidence that mammalian SOF1 is secreted. Our analyses of these genes begin to build a paradigm for sperm-secreted or reproductive-tract-secreted proteins that coat the sperm surface and influence their survival, motility, and/or the ability to fertilize the egg.
Topics: Animals; Male; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Amino Acid Sequence; Membrane Proteins; Semen; Spermatozoa; Fertilization; Sperm-Ovum Interactions; Sperm Proteins; Immunoglobulin Domains; Mammals
PubMed: 37453427
DOI: 10.1016/j.cub.2023.06.029