Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.
A specific mannose-binding member of the collectin family of lectins. It binds to carbohydrate groups on invading pathogens and plays a key role in the MANNOSE-BINDING LECTIN COMPLEMENT PATHWAY.
A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)
A subclass of lectins that are specific for CARBOHYDRATES that contain MANNOSE.
A class of C-type lectins that target the carbohydrate structures found on invading pathogens. Binding of collectins to microorganisms results in their agglutination and enhanced clearance. Collectins form trimers that may assemble into larger oligomers. Each collectin polypeptide chain consists of four regions: a relatively short N-terminal region, a collagen-like region, an alpha-helical coiled-coil region, and carbohydrate-binding region.
Protein or glycoprotein substances of plant origin that bind to sugar moieties in cell walls or membranes. Some carbohydrate-metabolizing proteins (ENZYMES) from PLANTS also bind to carbohydrates, however they are not considered lectins. Many plant lectins change the physiology of the membrane of BLOOD CELLS to cause agglutination, mitosis, or other biochemical changes. They may play a role in plant defense mechanisms.
Complement activation triggered by the interaction of microbial POLYSACCHARIDES with serum MANNOSE-BINDING LECTIN resulting in the activation of MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. As in the classical pathway, MASPs cleave COMPLEMENT C4 and COMPLEMENT C2 to form C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
Serum serine proteases which participate in COMPLEMENT ACTIVATION. They are activated when complexed with the MANNOSE-BINDING LECTIN, therefore also known as Mannose-binding protein-Associated Serine Proteases (MASPs). They cleave COMPLEMENT C4 and COMPLEMENT C2 to form C4b2a, the CLASSICAL PATHWAY C3 CONVERTASE.
A subcomponent of complement C1, composed of six copies of three polypeptide chains (A, B, and C), each encoded by a separate gene (C1QA; C1QB; C1QC). This complex is arranged in nine subunits (six disulfide-linked dimers of A and B, and three disulfide-linked homodimers of C). C1q has binding sites for antibodies (the heavy chain of IMMUNOGLOBULIN G or IMMUNOGLOBULIN M). The interaction of C1q and immunoglobulin activates the two proenzymes COMPLEMENT C1R and COMPLEMENT C1S, thus initiating the cascade of COMPLEMENT ACTIVATION via the CLASSICAL COMPLEMENT PATHWAY.
Transport proteins that carry specific substances in the blood or across cell membranes.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A class of animal lectins that bind to carbohydrate in a calcium-dependent manner. They share a common carbohydrate-binding domain that is structurally distinct from other classes of lectins.
A receptor that is specific for IGF-II and mannose-6-phosphate. The receptor is a 250-kDa single chain polypeptide which is unrelated in structure to the type 1 IGF receptor (RECEPTOR, IGF TYPE 1) and does not have a tyrosine kinase domain.
A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
Phosphoric acid esters of mannose.
A nucleoside diphosphate sugar which can be converted to the deoxy sugar GDPfucose, which provides fucose for lipopolysaccharides of bacterial cell walls. Also acts as mannose donor for glycolipid synthesis.
The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.
A lipophilic glycosyl carrier of the monosaccharide mannose in the biosynthesis of oligosaccharide phospholipids and glycoproteins.
Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.
Lectins purified from the germinating seeds of common wheat (Triticum vulgare); these bind to certain carbohydrate moieties on cell surface glycoproteins and are used to identify certain cell populations and inhibit or promote some immunological or physiological activities. There are at least two isoforms of this lectin.
The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.
A class of animal lectins that bind specifically to beta-galactoside in a calcium-independent manner. Members of this class are distiguished from other lectins by the presence of a conserved carbohydrate recognition domain. The majority of proteins in this class bind to sugar molecules in a sulfhydryl-dependent manner and are often referred to as S-type lectins, however this property is not required for membership in this class.
Carbohydrates covalently linked to a nonsugar moiety (lipids or proteins). The major glycoconjugates are glycoproteins, glycopeptides, peptidoglycans, glycolipids, and lipopolysaccharides. (From Biochemical Nomenclature and Related Documents, 2d ed; From Principles of Biochemistry, 2d ed)
Polysaccharides are complex carbohydrates consisting of long, often branched chains of repeating monosaccharide units joined together by glycosidic bonds, which serve as energy storage molecules (e.g., glycogen), structural components (e.g., cellulose), and molecular recognition sites in various biological systems.
Glycosides formed by the reaction of the hydroxyl group on the anomeric carbon atom of mannose with an alcohol to form an acetal. They include both alpha- and beta-mannosides.
A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.
Cellular processes in biosynthesis (anabolism) and degradation (catabolism) of CARBOHYDRATES.
The N-acetyl derivative of galactosamine.
An aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. Deficiency of galactosyl-1-phosphate uridyltransferase (GALACTOSE-1-PHOSPHATE URIDYL-TRANSFERASE DEFICIENCY DISEASE) causes an error in galactose metabolism called GALACTOSEMIA, resulting in elevations of galactose in the blood.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
A plant genus in the family LILIACEAE (sometimes classified as Amaryllidaceae). Galanthus nivalis L. is the source of GALANTHAMINE.
Simple sugars, carbohydrates which cannot be decomposed by hydrolysis. They are colorless crystalline substances with a sweet taste and have the same general formula CnH2nOn. (From Dorland, 28th ed)
The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.
Lectin purified from peanuts (ARACHIS HYPOGAEA). It binds to poorly differentiated cells and terminally differentiated cells and is used in cell separation techniques.
Fucose is a deoxyhexose sugar, specifically a L-configuration 6-deoxygalactose, often found as a component of complex carbohydrates called glycans in various glycoproteins and glycolipids within the human body.
Enzymes that catalyze the transfer of mannose from a nucleoside diphosphate mannose to an acceptor molecule which is frequently another carbohydrate. The group includes EC 2.4.1.32, EC 2.4.1.48, EC 2.4.1.54, and EC 2.4.1.57.
An enzyme that catalyzes the reversible isomerization of D-mannose-6-phosphate to form D-fructose-6-phosphate, an important step in glycolysis. EC 5.3.1.8.
Polysaccharides consisting of mannose units.
Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.

Sec24 proteins and sorting at the endoplasmic reticulum. (1/916)

COPII proteins are necessary to generate secretory vesicles at the endoplasmic reticulum. In yeast, the Sec24p protein is the only COPII component in which two close orthologues have been identified. By using gene knock-out in yeast, we found that the absence of one of these Sec24 orthologues resulted in a selective secretion defect for a subset of proteins released into the medium. Data base searches revealed the existence of an entire family of Sec24-related proteins in humans, worms, flies, and plants. We identified and cloned two new human cDNAs encoding proteins homologous to yeast Sec24p, in addition to two human cDNAs already present within the data bases. The entire Sec24 family identified to date is characterized by clusters of highly conserved residues within the 2/3 carboxyl-terminal domain of all the proteins and a divergent amino terminus domain. Human (h) Sec24 orthologues co-immunoprecipitate with hSec23Ap and migrate as a complex by size exclusion chromatography. Immunofluorescence microscopy confirmed that these proteins co-localize with hSec23p and hSec13p. Together, our data suggest that in addition to its role in the shaping up of the vesicle, the Sec23-24p complex may be implicated in cargo selection and concentration.  (+info)

PU.1 and USF are required for macrophage-specific mannose receptor promoter activity. (2/916)

In the current study we report the isolation of 854 base pairs of the rat mannose receptor promoter. Analysis of the sequence revealed one Sp1 site, three PU.1 sites, and a potential TATA box (TTTAAA) 33 base pairs 5' of the transcriptional start site. The tissue specificity of the promoter was determined using transient transfections. The promoter was most active in the mature macrophage cell line NR8383 although the promoter also showed activity in the monocytic cell line RAW. No activity was observed in pre-monocytic cell lines or epithelial cell lines. Mutation of the TTTAAA sequence to TTGGAA resulted in a 50% decrease in activity in transient transfection assays suggesting that the promoter contains a functional TATA box. Using electrophoretic mobility shift assays and mutagenesis we established that the transcription factors Sp1, PU.1, and USF bound to the mannose receptor promoter, but only PU.1 and USF contributed to activation. Transient transfections using a dominant negative construct of USF resulted in a 50% decrease in mannose receptor promoter activity, further establishing the role of USF in activating the rat mannose receptor promoter. Comparison of the rat, mouse, and human sequence demonstrated that some binding sites are not conserved. Gel shifts were performed to investigate differences in protein binding between species. USF bound to the rat and human promoter but not to the mouse promoter, suggesting that different mechanisms are involved in regulation of mannose receptor expression in these species. From these results we conclude that, similar to other myeloid promoters, transcription of the rat mannose receptor is regulated by binding of PU.1 and a ubiquitous factor at an adjacent site. However, unlike other myeloid promoters, we have identified USF as the ubiquitous factor, and demonstrated that the promoter contains a functional TATA box.  (+info)

Molecular analysis of the ERGIC-53 gene in 35 families with combined factor V-factor VIII deficiency. (3/916)

Combined factor V-factor VIII deficiency (F5F8D) is a rare, autosomal recessive coagulation disorder in which the levels of both coagulation factors V and VIII are diminished. The F5F8D locus was previously mapped to a 1-cM interval on chromosome 18q21. Mutations in a candidate gene in this region, ERGIC-53, were recently found to be associated with the coagulation defect in nine Jewish families. We performed single-strand conformation and sequence analysis of the ERGIC-53 gene in 35 F5F8D families of different ethnic origins. We identified 13 distinct mutations accounting for 52 of 70 mutant alleles. These were 3 splice site mutations, 6 insertions and deletions resulting in translational frameshifts, 3 nonsense codons, and elimination of the translation initiation codon. These mutations are predicted to result in synthesis of either a truncated protein product or no protein at all. This study revealed that F5F8D shows extensive allelic heterogeneity and all ERGIC-53 mutations resulting in F5F8D are "null." Approximately 26% of the mutations have not been identified, suggesting that lesions in regulatory elements or severe abnormalities within the introns may be responsible for the disease in these individuals. In two such families, ERGIC-53 protein was detectable at normal levels in patients' lymphocytes, raising the further possibility of defects at other genetic loci.  (+info)

ERGIC-53 gene structure and mutation analysis in 19 combined factors V and VIII deficiency families. (4/916)

Combined factors V and VIII deficiency is an autosomal recessive bleeding disorder associated with plasma levels of coagulation factors V and VIII approximately 5% to 30% of normal. The disease gene was recently identified as the endoplasmic reticulum-Golgi intermediate compartment protein ERGIC-53 by positional cloning, with the detection of two founder mutations in 10 Jewish families. To identify mutations in additional families, the structure of the ERGIC-53 gene was determined by genomic polymerase chain reaction (PCR) and sequence analysis of bacterial artificial chromosome clones containing the ERGIC-53 gene. Nineteen additional families were analyzed by direct sequence analysis of the entire coding region and the intron/exon junctions. Seven novel mutations were identified in 10 families, with one additional family found to harbor one of the two previously described mutations. All of the identified mutations would be predicted to result in complete absence of functional ERGIC-53 protein. In 8 of 19 families, no mutation was identified. Genotyping data indicate that at least two of these families are not linked to the ERGIC-53 locus. Taken together, these results suggest that a significant subset of combined factors V and VIII deficiency is due to mutation in one or more additional genes.  (+info)

Mapping of structural determinants for the oligomerization of p58, a lectin-like protein of the intermediate compartment and cis-Golgi. (5/916)

Shortly after synthesis, p58, the rat homologue of the mannose-binding lectin ERGIC-53/MR60, which localizes to pre-Golgi and cis-Golgi compartments, forms dimers and hexamers, after which an equilibrium of both forms is reached. Mature p58, a type I membrane protein, contains four cysteine residues in the lumenal domain which are capable of forming disulphide bonds. The membrane-proximal half of the lumenal domain consists of four predicted alpha-helical domains, one heavily charged and three amphipathic in nature, all candidates for electrostatic or coiled-coil interactions. Using single-stranded mutagenesis, the cysteines were individually changed to alanines and the contribution of each of the alpha-helical domains was probed by internal deletions. The N-terminal cysteine to alanine mutants, C198A and C238A and the double mutant, C198/238A, oligomerized like the wild-type protein. The two membrane-proximal cysteines were found to be necessary for the oligomerization of p58. Mutants lacking one of the membrane proximal cysteines, either C473A or C482A, were unable to form hexamers, while dimers were formed normally. The C473/482A double mutant formed only monomers. Deletion of any of the individual alpha-helical domains had no effect on oligomerization. The dimeric and hexameric forms bound equally well to D-mannose. The dimeric and monomeric mutants displayed a cellular distribution similar to the wild-type protein, indicating that the oligomerization status played a minimal role in maintaining the subcellular distribution of p58.  (+info)

A different intracellular distribution of a single reporter protein is determined at steady state by KKXX or KDEL retrieval signals. (6/916)

To establish the specific contribution to protein topology of KKXX and KDEL retrieval motifs, we have determined by immunogold electron microscopy and cell fractionation the intracellular distribution at steady state of the transmembrane and anchorless versions of human CD8 protein, tagged with KKXX (CD8-E19) and KDEL (CD8-K), respectively, and stably expressed in epithelial rat cells (Martire, G., Mottola, G., Pascale, M. C., Malagolini, N., Turrini, I., Serafini-Cessi, F., Jackson, M. R., and Bonatti, S. (1996) J. Biol. Chem. 271, 3541-3547). The CD8-E19 protein is represented by a single form, initially O-glycosylated: only about half of it is located in the endoplasmic reticulum, whereas more than 30% of the total is present in the intermediate compartment and cis-Golgi complex. In the latter compartments, CD8-E19 colocalizes with beta-coat protein (COP) (COPI component) and shows the higher density of labeling. Conversely, about 90% of the total CD8-KDEL protein is localized in clusters on the endoplasmic reticulum, where significant co-localization with Sec-23p (COPII component) is observed, and unglycosylated and initially O-glycosylated forms apparently constitute a single pool. Altogether, these results suggest that KKXX and KDEL retrieval motifs have different topological effects on theirs own at steady state: the first results in a specific enrichment in the intermediate compartment and cis-Golgi complex, and the latter dictates residency in the endoplasmic reticulum.  (+info)

Type 1 and type 2 cytokine regulation of macrophage endocytosis: differential activation by IL-4/IL-13 as opposed to IFN-gamma or IL-10. (7/916)

Cytokine regulation of endocytic activity in primary human macrophages was studied to define ultrastructural changes and mechanisms of pinocytic regulation associated with cytokines secreted by activated T cells. The effects of IFN-gamma (type 1) and IL-4/IL-13 and IL-10 (type 2) cytokines on fluid phase and mannose receptor-mediated endocytosis were assessed by horseradish peroxidase and colloidal gold-BSA uptake and computer-assisted morphometric analysis. IL-4 and IL-13 enhanced fluid phase pinocytosis and mannose receptor-mediated uptake by activation of phosphatidylinositol 3-kinase. Inhibition of actin assembly showed that both cytokines exerted actin-dependent and -independent effects. Ultrastructurally, IL-4 and IL-13 increased tubular vesicle formation underneath the plasma membrane and at pericentriolar sites, concurrent with decreased particle sorting to lysosomes. By contrast, IL-10 or IFN-gamma decreased both fluid phase pinocytosis and mannose receptor-mediated uptake. IFN-gamma stimulated increased particle sorting to perinuclear lysosomes, while IL-10 decreased this activity. In summary, our data document differential effects on macrophage endocytic functions by type 1 or type 2 cytokines associated with induction and effector pathways in immunity.  (+info)

A comparison of the pharmacological properties of carbohydrate remodeled recombinant and placental-derived beta-glucocerebrosidase: implications for clinical efficacy in treatment of Gaucher disease. (8/916)

The objective of these studies was to characterize the macrophage mannose receptor binding and pharmacological properties of carbohydrate remodeled human placental-derived and recombinant beta-glucocerebrosidase (pGCR and rGCR, respectively). These are similar but not identical molecules that were developed as enzyme replacement therapies for Gaucher disease. Both undergo oligosaccharide remodeling during purification to expose terminal mannose sugar residues. Competitive binding data indicated carbohydrate remodeling improved targeting to mannose receptors over native enzyme by two orders of magnitude. Mannose receptor dissociation constants (Kd) for pGCR and rGCR were each 13 nmol/L. At 37 degrees C, 95% of the total macrophage binding was mannose receptor specific. In vivo, pGCR and rGCR were cleared from circulation by a saturable pathway. The serum half-life (t1/2) was 3 minutes when less than saturable amounts were injected intravenously (IV) into mice. Twenty minutes postdose, beta-glucocerebrosidase activity increased over endogenous levels in all tissues examined. Fifty percent of the injected activity was recovered. Ninety-five percent of recovered activity was in the liver. Parenchymal cells (PC), Kupffer cells (KC), and liver endothelium cells (LEC) were responsible for 75%, 22%, and 3%, respectively, of the hepatocellular uptake of rGCR and for 76%, 11%, and 12%, respectively, of the hepatocellular uptake of pGCR. Both molecules had poor stability in LEC and relatively long terminal half-lives in PC (t1/2 = 2 days) and KC (t1/2 = 3 days).  (+info)

Lectins are a type of proteins that bind specifically to carbohydrates and have been found in various plant and animal sources. They play important roles in biological recognition events, such as cell-cell adhesion, and can also be involved in the immune response. Some lectins can agglutinate certain types of cells or precipitate glycoproteins, while others may have a more direct effect on cellular processes. In some cases, lectins from plants can cause adverse effects in humans if ingested, such as digestive discomfort or allergic reactions.

Mannose-Binding Lectin (MBL) is a protein that belongs to the collectin family and plays a crucial role in the innate immune system. It's primarily produced by the liver and secreted into the bloodstream. MBL binds to carbohydrate structures, such as mannose, found on the surface of various microorganisms, including bacteria, viruses, fungi, and parasites.

Once MBL binds to these microorganisms, it activates the complement system through the lectin pathway, which leads to the destruction of the pathogens by opsonization (marking for phagocytosis) or direct lysis. Additionally, MBL can also initiate other immune responses, such as inflammation and immune cell activation, helping to protect the host from infections.

Deficiencies in MBL have been associated with increased susceptibility to certain infectious diseases, autoimmune disorders, and allergies. However, more research is needed to fully understand the complex role of MBL in human health and disease.

Mannose is a simple sugar (monosaccharide) that is similar in structure to glucose. It is a hexose, meaning it contains six carbon atoms. Mannose is a stereoisomer of glucose, meaning it has the same chemical formula but a different structural arrangement of its atoms.

Mannose is not as commonly found in foods as other simple sugars, but it can be found in some fruits, such as cranberries, blueberries, and peaches, as well as in certain vegetables, like sweet potatoes and turnips. It is also found in some dietary fibers, such as those found in beans and whole grains.

In the body, mannose can be metabolized and used for energy, but it is also an important component of various glycoproteins and glycolipids, which are molecules that play critical roles in many biological processes, including cell recognition, signaling, and adhesion.

Mannose has been studied as a potential therapeutic agent for various medical conditions, including urinary tract infections (UTIs), because it can inhibit the attachment of certain bacteria to the cells lining the urinary tract. Additionally, mannose-binding lectins have been investigated for their potential role in the immune response to viral and bacterial infections.

Mannose-binding lectins (MBLs) are a group of proteins that belong to the collectin family and play a crucial role in the innate immune system. They are primarily produced by the liver and secreted into the bloodstream. MBLs have a specific affinity for mannose sugar residues found on the surface of various microorganisms, including bacteria, viruses, fungi, and parasites.

The primary function of MBLs is to recognize and bind to these mannose-rich structures, which triggers the complement system's activation through the lectin pathway. This process leads to the destruction of the microorganism by opsonization (coating the microbe to enhance phagocytosis) or direct lysis. MBLs also have the ability to neutralize certain viruses and inhibit the replication of others, further contributing to their antimicrobial activity.

Deficiencies in MBL levels or function have been associated with an increased susceptibility to infections, particularly in children and older adults. However, the clinical significance of MBL deficiency remains a subject of ongoing research.

Collectins are a group of proteins that belong to the collectin family, which are involved in the innate immune system. They are composed of a collagen-like region and a carbohydrate recognition domain (CRD), which allows them to bind to specific sugars on the surface of microorganisms, cells, and particles. Collectins play a crucial role in the defense against pathogens by promoting the clearance of microbes, modulating inflammation, and regulating immune responses.

Some examples of collectins include:

* Surfactant protein A (SP-A) and surfactant protein D (SP-D), which are found in the lungs and help to maintain the stability of the lung lining and protect against respiratory infections.
* Mannose-binding lectin (MBL), which is a serum protein that binds to mannose sugars on the surface of microorganisms, activating the complement system and promoting phagocytosis.
* Collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1), which are found in the liver and kidneys, respectively, and play a role in the clearance of apoptotic cells and immune complexes.

Deficiencies or mutations in collectins can lead to increased susceptibility to infections, autoimmune diseases, and other disorders.

Plant lectins are proteins or glycoproteins that are abundantly found in various plant parts such as seeds, leaves, stems, and roots. They have the ability to bind specifically to carbohydrate structures present on cell membranes, known as glycoconjugates. This binding property of lectins is reversible and non-catalytic, meaning it does not involve any enzymatic activity.

Lectins play several roles in plants, including defense against predators, pathogens, and herbivores. They can agglutinate red blood cells, stimulate the immune system, and have been implicated in various biological processes such as cell growth, differentiation, and apoptosis (programmed cell death). Some lectins also exhibit mitogenic activity, which means they can stimulate the proliferation of certain types of cells.

In the medical field, plant lectins have gained attention due to their potential therapeutic applications. For instance, some lectins have been shown to possess anti-cancer properties and are being investigated as potential cancer treatments. However, it is important to note that some lectins can be toxic or allergenic to humans and animals, so they must be used with caution.

The Mannose-Binding Lectin (MBL) pathway is a part of the complement system, which is a group of proteins that play a crucial role in the body's immune defense against infectious agents. The MBL pathway is an alternative activation pathway of the complement system, which can be initiated without the need for antibodies.

MBL is a protein found in blood plasma and other bodily fluids. It recognizes and binds to specific sugars (mannose and fucose) found on the surface of many microorganisms, including bacteria, viruses, fungi, and parasites. When MBL binds to these sugars, it triggers a series of proteolytic cleavage events that activate the complement components C4 and C2, forming the C3 convertase (C4b2a).

The C3 convertase then cleaves the complement component C3 into C3a and C3b. C3b can bind to the surface of microorganisms, leading to their opsonization (coating) and subsequent phagocytosis by immune cells. Additionally, C3b can also trigger the formation of the membrane attack complex (MAC), which creates a pore in the membrane of microorganisms, leading to their lysis and death.

Overall, the MBL pathway plays an essential role in innate immunity, providing a rapid and effective defense against invading microorganisms.

Mannose-binding protein-associated serine proteases (MASPs) are a group of enzymes that are associated with mannose-binding lectin (MBL), a protein involved in the innate immune system's response to pathogens. MASPs are responsible for activating the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body.

MASPs are proteases, meaning they cleave other proteins at specific sites. There are two main types of MASPs, MASP-1 and MASP-2, which are activated by the binding of MBL to carbohydrate structures on the surface of pathogens. Once activated, MASP-1 and MASP-2 cleave complement components C4 and C2, leading to the formation of the C3 convertase enzyme complex, which ultimately results in the activation of the complement system.

MASPs have also been shown to play a role in other physiological processes, such as tissue remodeling and inflammation. Mutations in MASP genes have been associated with various immune disorders, including recurrent infections, autoimmune diseases, and inflammatory conditions.

Complement C1q is a protein that is part of the complement system, which is a group of proteins in the blood that help to eliminate pathogens and damaged cells from the body. C1q is the first component of the classical complement pathway, which is activated by the binding of C1q to antibodies that are attached to the surface of a pathogen or damaged cell.

C1q is composed of six identical polypeptide chains, each containing a collagen-like region and a globular head region. The globular heads can bind to various structures, including the Fc regions of certain antibodies, immune complexes, and some types of cells. When C1q binds to an activating surface, it triggers a series of proteolytic reactions that lead to the activation of other complement components and the formation of the membrane attack complex (MAC), which can punch holes in the membranes of pathogens or damaged cells, leading to their destruction.

In addition to its role in the immune system, C1q has also been found to have roles in various physiological processes, including tissue remodeling, angiogenesis, and the clearance of apoptotic cells. Dysregulation of the complement system, including abnormalities in C1q function, has been implicated in a variety of diseases, including autoimmune disorders, inflammatory diseases, and neurodegenerative conditions.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Genotype, in genetics, refers to the complete heritable genetic makeup of an individual organism, including all of its genes. It is the set of instructions contained in an organism's DNA for the development and function of that organism. The genotype is the basis for an individual's inherited traits, and it can be contrasted with an individual's phenotype, which refers to the observable physical or biochemical characteristics of an organism that result from the expression of its genes in combination with environmental influences.

It is important to note that an individual's genotype is not necessarily identical to their genetic sequence. Some genes have multiple forms called alleles, and an individual may inherit different alleles for a given gene from each parent. The combination of alleles that an individual inherits for a particular gene is known as their genotype for that gene.

Understanding an individual's genotype can provide important information about their susceptibility to certain diseases, their response to drugs and other treatments, and their risk of passing on inherited genetic disorders to their offspring.

Genetic polymorphism refers to the occurrence of multiple forms (called alleles) of a particular gene within a population. These variations in the DNA sequence do not generally affect the function or survival of the organism, but they can contribute to differences in traits among individuals. Genetic polymorphisms can be caused by single nucleotide changes (SNPs), insertions or deletions of DNA segments, or other types of genetic rearrangements. They are important for understanding genetic diversity and evolution, as well as for identifying genetic factors that may contribute to disease susceptibility in humans.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

C-type lectins are a family of proteins that contain one or more carbohydrate recognition domains (CRDs) with a characteristic pattern of conserved sequence motifs. These proteins are capable of binding to specific carbohydrate structures in a calcium-dependent manner, making them important in various biological processes such as cell adhesion, immune recognition, and initiation of inflammatory responses.

C-type lectins can be further classified into several subfamilies based on their structure and function, including selectins, collectins, and immunoglobulin-like receptors. They play a crucial role in the immune system by recognizing and binding to carbohydrate structures on the surface of pathogens, facilitating their clearance by phagocytic cells. Additionally, C-type lectins are involved in various physiological processes such as cell development, tissue repair, and cancer progression.

It is important to note that some C-type lectins can also bind to self-antigens and contribute to autoimmune diseases. Therefore, understanding the structure and function of these proteins has important implications for developing new therapeutic strategies for various diseases.

IGF-2 (Insulin-like Growth Factor 2) receptor is a type of transmembrane protein that plays a role in cell growth, differentiation, and survival. Unlike other receptors in the insulin and IGF family, IGF-2 receptor does not mediate the activation of intracellular signaling pathways upon binding to its ligand (IGF-2). Instead, it acts as a clearance receptor that facilitates the removal of IGF-2 from circulation by transporting it to lysosomes for degradation.

The IGF-2 receptor is also known as cation-independent mannose-6-phosphate receptor (CI-M6PR) because it can also bind and transport mannose-6-phosphate-containing enzymes to lysosomes for degradation.

Mutations in the IGF-2 receptor gene have been associated with certain types of cancer, as well as developmental disorders such as Beckwith-Wiedemann syndrome.

Genetic predisposition to disease refers to an increased susceptibility or vulnerability to develop a particular illness or condition due to inheriting specific genetic variations or mutations from one's parents. These genetic factors can make it more likely for an individual to develop a certain disease, but it does not guarantee that the person will definitely get the disease. Environmental factors, lifestyle choices, and interactions between genes also play crucial roles in determining if a genetically predisposed person will actually develop the disease. It is essential to understand that having a genetic predisposition only implies a higher risk, not an inevitable outcome.

I'm sorry for any confusion, but "Mannosephosphates" is not a widely recognized or established term in medicine or biochemistry. It seems that this term may be a combination of "mannose," which is a type of sugar (monosaccharide), and "phosphates," which are compounds containing phosphorus. However, without more context, it's difficult to provide an accurate medical definition for this term.

In biochemistry, mannose can be linked to phosphate groups in various ways, such as in the context of mannose-1-phosphate or mannose-6-phosphate, which are involved in different metabolic pathways. If you could provide more information about where you encountered this term, I might be able to give a more precise definition or explanation.

Guanosine diphosphate mannose (GDP-mannose) is a nucleotide sugar that plays a crucial role in the biosynthesis of various glycans, including those found on proteins and lipids. It is formed from mannose-1-phosphate through the action of the enzyme mannose-1-phosphate guanylyltransferase, using guanosine triphosphate (GTP) as a source of energy.

GDP-mannose serves as a donor substrate for several glycosyltransferases involved in the biosynthesis of complex carbohydrates, such as those found in glycoproteins and glycolipids. It is also used in the synthesis of certain polysaccharides, like bacterial cell wall components.

Defects in the metabolism or utilization of GDP-mannose can lead to various genetic disorders, such as congenital disorders of glycosylation (CDG), which can affect multiple organ systems and present with a wide range of clinical manifestations.

Carbohydrates are a major nutrient class consisting of organic compounds that primarily contain carbon, hydrogen, and oxygen atoms. They are classified as saccharides, which include monosaccharides (simple sugars), disaccharides (double sugars), oligosaccharides (short-chain sugars), and polysaccharides (complex carbohydrates).

Monosaccharides, such as glucose, fructose, and galactose, are the simplest form of carbohydrates. They consist of a single sugar molecule that cannot be broken down further by hydrolysis. Disaccharides, like sucrose (table sugar), lactose (milk sugar), and maltose (malt sugar), are formed from two monosaccharide units joined together.

Oligosaccharides contain a small number of monosaccharide units, typically less than 20, while polysaccharides consist of long chains of hundreds to thousands of monosaccharide units. Polysaccharides can be further classified into starch (found in plants), glycogen (found in animals), and non-starchy polysaccharides like cellulose, chitin, and pectin.

Carbohydrates play a crucial role in providing energy to the body, with glucose being the primary source of energy for most cells. They also serve as structural components in plants (cellulose) and animals (chitin), participate in various metabolic processes, and contribute to the taste, texture, and preservation of foods.

Dolichol monophosphate mannose (Dol-P-Man) is a type of glycosyl donor that plays a crucial role in the process of protein glycosylation within the endoplasmic reticulum (ER) of eukaryotic cells. Protein glycosylation is the enzymatic attachment of oligosaccharide chains to proteins, which can significantly affect their structure, stability, and function.

Dolichol monophosphate mannose consists of a dolichol molecule, a long-chain polyisoprenoid alcohol, linked to a mannose sugar via a phosphate group. The dolichol component serves as a lipid anchor, allowing Dol-P-Man to participate in the synthesis of oligosaccharides on the cytoplasmic side of the ER membrane.

In the first step of the process, mannose is transferred from a donor molecule, guanosine diphosphate mannose (GDP-Man), to dolichol phosphate (Dol-P) by the enzyme alpha-1,2-mannosyltransferase. This reaction forms Dol-P-Man, which then serves as a substrate for further glycosylation reactions in the ER lumen.

In summary, Dolichol monophosphate mannose is an essential intermediate in the biosynthesis of N-linked oligosaccharides, contributing to the proper folding and functioning of proteins within eukaryotic cells.

Oligosaccharides are complex carbohydrates composed of relatively small numbers (3-10) of monosaccharide units joined together by glycosidic linkages. They occur naturally in foods such as milk, fruits, vegetables, and legumes. In the body, oligosaccharides play important roles in various biological processes, including cell recognition, signaling, and protection against pathogens.

There are several types of oligosaccharides, classified based on their structures and functions. Some common examples include:

1. Disaccharides: These consist of two monosaccharide units, such as sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).
2. Trisaccharides: These contain three monosaccharide units, like maltotriose (glucose + glucose + glucose) and raffinose (galactose + glucose + fructose).
3. Oligosaccharides found in human milk: Human milk contains unique oligosaccharides that serve as prebiotics, promoting the growth of beneficial bacteria in the gut. These oligosaccharides also help protect infants from pathogens by acting as decoy receptors and inhibiting bacterial adhesion to intestinal cells.
4. N-linked and O-linked glycans: These are oligosaccharides attached to proteins in the body, playing crucial roles in protein folding, stability, and function.
5. Plant-derived oligosaccharides: Fructooligosaccharides (FOS) and galactooligosaccharides (GOS) are examples of plant-derived oligosaccharides that serve as prebiotics, promoting the growth of beneficial gut bacteria.

Overall, oligosaccharides have significant impacts on human health and disease, particularly in relation to gastrointestinal function, immunity, and inflammation.

Wheat germ agglutinins (WGA) are proteins found in wheat germ that have the ability to bind to specific carbohydrate structures, such as N-acetylglucosamine and sialic acid, which are present on the surface of many cells in the human body. WGA is a type of lectin, a group of proteins that can agglutinate, or clump together, red blood cells and bind to specific sugars on cell membranes.

WGA has been studied for its potential effects on various biological processes, including inflammation, immune response, and gut barrier function. Some research suggests that WGA may interact with the gut epithelium and affect intestinal permeability, potentially contributing to the development of gastrointestinal symptoms in some individuals. However, more research is needed to fully understand the clinical significance of these findings.

It's worth noting that while WGA has been studied for its potential biological effects, it is not currently recognized as a major allergen or toxic component of wheat. However, some people may still choose to avoid foods containing WGA due to personal dietary preferences or sensitivities.

A "carbohydrate sequence" refers to the specific arrangement or order of monosaccharides (simple sugars) that make up a carbohydrate molecule, such as a polysaccharide or an oligosaccharide. Carbohydrates are often composed of repeating units of monosaccharides, and the sequence in which these units are arranged can have important implications for the function and properties of the carbohydrate.

For example, in glycoproteins (proteins that contain carbohydrate chains), the specific carbohydrate sequence can affect how the protein is processed and targeted within the cell, as well as its stability and activity. Similarly, in complex carbohydrates like starch or cellulose, the sequence of glucose units can determine whether the molecule is branched or unbranched, which can have implications for its digestibility and other properties.

Therefore, understanding the carbohydrate sequence is an important aspect of studying carbohydrate structure and function in biology and medicine.

Galectins are a family of animal lectins (carbohydrate-binding proteins) that bind specifically to beta-galactosides. They play important roles in various biological processes, including inflammation, immune response, cancer progression, and development. Galectins are widely distributed in various tissues and organ systems, and they can be found both intracellularly and extracellularly.

There are 15 known mammalian galectins, which are classified into three groups based on their structure: prototype (Gal-1, -2, -5, -7, -10, -13, -14, and -16), chimera-type (Gal-3), and tandem-repeat type (Gal-4, -6, -8, -9, and -12). Each galectin has a unique set of functions, but they often work together to regulate cellular processes.

Abnormal expression or function of galectins has been implicated in various diseases, including cancer, fibrosis, and autoimmune disorders. Therefore, galectins are considered potential targets for the development of new therapeutic strategies.

Glycoconjugates are a type of complex molecule that form when a carbohydrate (sugar) becomes chemically linked to a protein or lipid (fat) molecule. This linkage, known as a glycosidic bond, results in the formation of a new molecule that combines the properties and functions of both the carbohydrate and the protein or lipid component.

Glycoconjugates can be classified into several categories based on the type of linkage and the nature of the components involved. For example, glycoproteins are glycoconjugates that consist of a protein backbone with one or more carbohydrate chains attached to it. Similarly, glycolipids are molecules that contain a lipid anchor linked to one or more carbohydrate residues.

Glycoconjugates play important roles in various biological processes, including cell recognition, signaling, and communication. They are also involved in the immune response, inflammation, and the development of certain diseases such as cancer and infectious disorders. As a result, understanding the structure and function of glycoconjugates is an active area of research in biochemistry, cell biology, and medical science.

Polysaccharides are complex carbohydrates consisting of long chains of monosaccharide units (simple sugars) bonded together by glycosidic linkages. They can be classified based on the type of monosaccharides and the nature of the bonds that connect them.

Polysaccharides have various functions in living organisms. For example, starch and glycogen serve as energy storage molecules in plants and animals, respectively. Cellulose provides structural support in plants, while chitin is a key component of fungal cell walls and arthropod exoskeletons.

Some polysaccharides also have important roles in the human body, such as being part of the extracellular matrix (e.g., hyaluronic acid) or acting as blood group antigens (e.g., ABO blood group substances).

Mannosides are glycosylated compounds that consist of a mannose sugar molecule (a type of monosaccharide) linked to another compound, often a protein or lipid. They are formed when an enzyme called a glycosyltransferase transfers a mannose molecule from a donor substrate, such as a nucleotide sugar (like GDP-mannose), to an acceptor molecule.

Mannosides can be found on the surface of many types of cells and play important roles in various biological processes, including cell recognition, signaling, and protein folding. They are also involved in the immune response and have been studied as potential therapeutic targets for a variety of diseases, including infectious diseases and cancer.

It's worth noting that mannosides can be further classified based on the specific linkage between the mannose molecule and the acceptor compound. For example, an N-linked mannoside is one in which the mannose is linked to a nitrogen atom on the acceptor protein, while an O-linked mannoside is one in which the mannose is linked to an oxygen atom on the acceptor protein.

Concanavalin A (Con A) is a type of protein known as a lectin, which is found in the seeds of the plant Canavalia ensiformis, also known as jack bean. It is often used in laboratory settings as a tool to study various biological processes, such as cell division and the immune response, due to its ability to bind specifically to certain sugars on the surface of cells. Con A has been extensively studied for its potential applications in medicine, including as a possible treatment for cancer and viral infections. However, more research is needed before these potential uses can be realized.

Carbohydrate metabolism is the process by which the body breaks down carbohydrates into glucose, which is then used for energy or stored in the liver and muscles as glycogen. This process involves several enzymes and chemical reactions that convert carbohydrates from food into glucose, fructose, or galactose, which are then absorbed into the bloodstream and transported to cells throughout the body.

The hormones insulin and glucagon regulate carbohydrate metabolism by controlling the uptake and storage of glucose in cells. Insulin is released from the pancreas when blood sugar levels are high, such as after a meal, and promotes the uptake and storage of glucose in cells. Glucagon, on the other hand, is released when blood sugar levels are low and signals the liver to convert stored glycogen back into glucose and release it into the bloodstream.

Disorders of carbohydrate metabolism can result from genetic defects or acquired conditions that affect the enzymes or hormones involved in this process. Examples include diabetes, hypoglycemia, and galactosemia. Proper management of these disorders typically involves dietary modifications, medication, and regular monitoring of blood sugar levels.

Acetylgalactosamine (also known as N-acetyl-D-galactosamine or GalNAc) is a type of sugar molecule called a hexosamine that is commonly found in glycoproteins and proteoglycans, which are complex carbohydrates that are attached to proteins and lipids. It plays an important role in various biological processes, including cell-cell recognition, signal transduction, and protein folding.

In the context of medical research and biochemistry, Acetylgalactosamine is often used as a building block for synthesizing glycoconjugates, which are molecules that consist of a carbohydrate attached to a protein or lipid. These molecules play important roles in many biological processes, including cell-cell recognition, signaling, and immune response.

Acetylgalactosamine is also used as a target for enzymes called glycosyltransferases, which add sugar molecules to proteins and lipids. In particular, Acetylgalactosamine is the acceptor substrate for a class of glycosyltransferases known as galactosyltransferases, which add galactose molecules to Acetylgalactosamine-containing structures.

Defects in the metabolism of Acetylgalactosamine have been linked to various genetic disorders, including Schindler disease and Kanzaki disease, which are characterized by neurological symptoms and abnormal accumulation of glycoproteins in various tissues.

Galactose is a simple sugar or monosaccharide that is a constituent of lactose, the disaccharide found in milk and dairy products. It's structurally similar to glucose but with a different chemical structure, and it plays a crucial role in various biological processes.

Galactose can be metabolized in the body through the action of enzymes such as galactokinase, galactose-1-phosphate uridylyltransferase, and UDP-galactose 4'-epimerase. Inherited deficiencies in these enzymes can lead to metabolic disorders like galactosemia, which can cause serious health issues if not diagnosed and treated promptly.

In summary, Galactose is a simple sugar that plays an essential role in lactose metabolism and other biological processes.

Glycoproteins are complex proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbone. These glycans are linked to the protein through asparagine residues (N-linked) or serine/threonine residues (O-linked). Glycoproteins play crucial roles in various biological processes, including cell recognition, cell-cell interactions, cell adhesion, and signal transduction. They are widely distributed in nature and can be found on the outer surface of cell membranes, in extracellular fluids, and as components of the extracellular matrix. The structure and composition of glycoproteins can vary significantly depending on their function and location within an organism.

"Galanthus" is not a medical term. It is the genus name for snowdrops, a type of small, white flowering plant that typically blooms in early spring. The name "Galanthus" comes from the Greek words "gala," meaning milk, and "anthos," meaning flower, referring to the plant's white, milk-like flowers.

Snowdrops have been used in traditional medicine in some cultures, but there is limited scientific evidence to support their effectiveness for any specific medical purpose. Some studies suggest that certain compounds found in snowdrops may have potential therapeutic benefits, such as anti-inflammatory and neuroprotective effects, but more research is needed before any definitive conclusions can be drawn.

Monosaccharides are simple sugars that cannot be broken down into simpler units by hydrolysis. They are the most basic unit of carbohydrates and are often referred to as "simple sugars." Monosaccharides typically contain three to seven atoms of carbon, but the most common monosaccharides contain five or six carbon atoms.

The general formula for a monosaccharide is (CH2O)n, where n is the number of carbon atoms in the molecule. The majority of monosaccharides have a carbonyl group (aldehyde or ketone) and multiple hydroxyl groups. These functional groups give monosaccharides their characteristic sweet taste and chemical properties.

The most common monosaccharides include glucose, fructose, and galactose, all of which contain six carbon atoms and are known as hexoses. Other important monosaccharides include pentoses (five-carbon sugars) such as ribose and deoxyribose, which play crucial roles in the structure and function of nucleic acids (DNA and RNA).

Monosaccharides can exist in various forms, including linear and cyclic structures. In aqueous solutions, monosaccharides often form cyclic structures through a reaction between the carbonyl group and a hydroxyl group, creating a hemiacetal or hemiketal linkage. These cyclic structures can adopt different conformations, known as anomers, depending on the orientation of the hydroxyl group attached to the anomeric carbon atom.

Monosaccharides serve as essential building blocks for complex carbohydrates, such as disaccharides (e.g., sucrose, lactose, and maltose) and polysaccharides (e.g., starch, cellulose, and glycogen). They also participate in various biological processes, including energy metabolism, cell recognition, and protein glycosylation.

Glycosylation is the enzymatic process of adding a sugar group, or glycan, to a protein, lipid, or other organic molecule. This post-translational modification plays a crucial role in modulating various biological functions, such as protein stability, trafficking, and ligand binding. The structure and composition of the attached glycans can significantly influence the functional properties of the modified molecule, contributing to cell-cell recognition, signal transduction, and immune response regulation. Abnormal glycosylation patterns have been implicated in several disease states, including cancer, diabetes, and neurodegenerative disorders.

Peanut agglutinin (PNA) is a lectin, a type of carbohydrate-binding protein, found in peanuts. It is known to bind specifically to Galβ1-3GalNAc, a disaccharide present on glycoproteins and glycolipids of various cells. PNA has been used in research as a tool for identifying and isolating specific cell types, such as immature red blood cells (reticulocytes) and certain types of cancer cells, due to its affinity for these structures. However, it's important to note that peanut agglutinin may also have potential implications in the development of allergies to peanuts.

Fucose is a type of sugar molecule that is often found in complex carbohydrates known as glycans, which are attached to many proteins and lipids in the body. It is a hexose sugar, meaning it contains six carbon atoms, and is a type of L-sugar, which means that it rotates plane-polarized light in a counterclockwise direction.

Fucose is often found at the ends of glycan chains and plays important roles in various biological processes, including cell recognition, signaling, and interaction. It is also a component of some blood group antigens and is involved in the development and function of the immune system. Abnormalities in fucosylation (the addition of fucose to glycans) have been implicated in various diseases, including cancer, inflammation, and neurological disorders.

Mannosyltransferases are a group of enzymes that catalyze the transfer of mannose (a type of sugar) to specific acceptor molecules during the process of glycosylation. Glycosylation is the attachment of carbohydrate groups, or glycans, to proteins and lipids, which plays a crucial role in various biological processes such as protein folding, quality control, trafficking, and cell-cell recognition.

In particular, mannosyltransferases are involved in the addition of mannose residues to the core oligosaccharide structure of N-linked glycans in the endoplasmic reticulum (ER) and Golgi apparatus of eukaryotic cells. These enzymes use a donor substrate, typically dolichol-phosphate-mannose (DPM), to add mannose molecules to the acceptor substrate, which is an asparagine residue within a growing glycan chain.

There are several classes of mannosyltransferases, each responsible for adding mannose to specific positions within the glycan structure. Defects in these enzymes can lead to various genetic disorders known as congenital disorders of glycosylation (CDG), which can affect multiple organ systems and result in a wide range of clinical manifestations.

Mannose-6-Phosphate Isomerase (MPI) is an enzyme that catalyzes the interconversion between mannose-6-phosphate and fructose-6-phosphate, which are both key metabolites in the glycolysis and gluconeogenesis pathways. This enzyme plays a crucial role in maintaining the balance between these two metabolic pathways, allowing cells to either break down or synthesize glucose depending on their energy needs.

The gene that encodes for MPI is called MPI1 and is located on chromosome 4 in humans. Defects in this gene can lead to a rare genetic disorder known as Mannose-6-Phosphate Isomerase Deficiency or Congenital Disorder of Glycosylation Type IIm, which is characterized by developmental delay, intellectual disability, seizures, and various other neurological symptoms.

Mannans are a type of complex carbohydrate, specifically a heteropolysaccharide, that are found in the cell walls of certain plants, algae, and fungi. They consist of chains of mannose sugars linked together, often with other sugar molecules such as glucose or galactose.

Mannans have various biological functions, including serving as a source of energy for microorganisms that can break them down. In some cases, mannans can also play a role in the immune response and are used as a component of vaccines to stimulate an immune response.

In the context of medicine, mannans may be relevant in certain conditions such as gut dysbiosis or allergic reactions to foods containing mannans. Additionally, some research has explored the potential use of mannans as a delivery vehicle for drugs or other therapeutic agents.

Cell surface receptors, also known as membrane receptors, are proteins located on the cell membrane that bind to specific molecules outside the cell, known as ligands. These receptors play a crucial role in signal transduction, which is the process of converting an extracellular signal into an intracellular response.

Cell surface receptors can be classified into several categories based on their structure and mechanism of action, including:

1. Ion channel receptors: These receptors contain a pore that opens to allow ions to flow across the cell membrane when they bind to their ligands. This ion flux can directly activate or inhibit various cellular processes.
2. G protein-coupled receptors (GPCRs): These receptors consist of seven transmembrane domains and are associated with heterotrimeric G proteins that modulate intracellular signaling pathways upon ligand binding.
3. Enzyme-linked receptors: These receptors possess an intrinsic enzymatic activity or are linked to an enzyme, which becomes activated when the receptor binds to its ligand. This activation can lead to the initiation of various signaling cascades within the cell.
4. Receptor tyrosine kinases (RTKs): These receptors contain intracellular tyrosine kinase domains that become activated upon ligand binding, leading to the phosphorylation and activation of downstream signaling molecules.
5. Integrins: These receptors are transmembrane proteins that mediate cell-cell or cell-matrix interactions by binding to extracellular matrix proteins or counter-receptors on adjacent cells. They play essential roles in cell adhesion, migration, and survival.

Cell surface receptors are involved in various physiological processes, including neurotransmission, hormone signaling, immune response, and cell growth and differentiation. Dysregulation of these receptors can contribute to the development of numerous diseases, such as cancer, diabetes, and neurological disorders.

  • Deficiency of the mannose-binding lectin (MBL) protein, an antigen-recognition molecule involved in systemic and mucosal innate immunity, is determined by variant alleles in MBL2 gene promoter and exon-1 regions. (elsevierpure.com)
  • Mannose-binding lectin (MBL) deficiency, defined as MBL protein level of less than 100 ng/ml, is present in about 5% of people of European descent and in about 10% of sub-Saharan Africans. (nih.gov)
  • Mannose-binding lectin deficiency is a condition that affects the immune system. (nih.gov)
  • People with this condition have low levels (deficiency) of an immune system protein called mannose-binding lectin in their blood. (nih.gov)
  • People with mannose-binding lectin deficiency can develop infections of the upper respiratory tract and other body systems. (nih.gov)
  • Infants and young children with mannose-binding lectin deficiency seem to be more susceptible to infections than affected adults, but adults can also develop recurrent infections. (nih.gov)
  • Mannose Binding Lectin, IgG Subclass and Antibody Deficiency: Efficacy of Intravenous Immunoglobulins. (yumaregional.org)
  • Another important function of MBL is that this molecule binds senescent and apoptotic cells and enhances engulfment of whole, intact apoptotic cells, as well as cell debris by phagocytes. (wikipedia.org)
  • Melinda also has a particular interest in innate immune protein and pattern recognition molecule mannose binding lectin. (edu.au)
  • ArtinM is a D-mannose carbohydrate-binding lectin that interacts with phagocytic cell receptors inducing the production of pro-inflammatory mediators related to the antitumor immune response. (usp.br)
  • Mannose-Binding Lectin 2 Gene Polymorphism in PANDAS Patients. (cdc.gov)
  • Mannose-binding lectin (MBL), also called mannan-binding lectin or mannan-binding protein (MBP), is a lectin that is instrumental in innate immunity as an opsonin and via the lectin pathway. (wikipedia.org)
  • Do not miss to order the product Human Mannma binding protein/mannan binding lectin,MBP/MBL ELISA Kit at this promotional price until the end of December 2017. (assayspro.com)
  • After delivery, the specialists from Gentaur/Genprice recommend you to store the Human Mannma binding protein/mannan binding lectin,MBP/MBL ELISA Kit between two and eight degrees Celsius to keep the quality and activity of the reagents included in the kit. (assayspro.com)
  • Glycans, either alone or complexed with glycan-binding proteins, can deliver intracellular signals or control extracellular processes that promote initiation, execution and resolution of cell death programs. (nature.com)
  • Herein, we review the role of glycans and glycan-binding proteins as essential components of the cell death machinery during physiologic and pathologic settings. (nature.com)
  • At that time, glycobiology, which is the study of carbohydrates and their recognition by motif-specific carbohydrate-binding proteins or lectins, lagged far behind the studies that defined the structural and cellular biology of cell death. (nature.com)
  • Binding of MBL to a micro-organism results in activation of the lectin pathway of the complement system. (wikipedia.org)
  • The complement system can be activated through three pathways: the classical pathway, the alternative pathway, and the lectin pathway. (wikipedia.org)
  • In order to activate the complement system when MBL binds to its target (for example, mannose on the surface of a bacterium), the MASP protein functions to cleave the blood protein C4 into C4a and C4b. (wikipedia.org)
  • Activation of the complement system occurs through the classical (CP), lectin (LP), or alternative (AP) pathways. (jrheum.org)
  • How do C-type lectins tailor adaptive immunity following phagocytosis of apoptotic cells? (nature.com)
  • Mannose-binding lectin (MBL) is an innate immune protein with strong biologic plausibility for protecting against influenza virus-related sepsis and bacterial co-infection. (escholarship.org)
  • MBL binds to carbohydrates (to be specific, D-mannose and L-fucose residues) found on the surfaces of many pathogens. (wikipedia.org)
  • A subclass of lectins that are specific for CARBOHYDRATES that contain MANNOSE. (bvsalud.org)
  • Cell detachment from pyrite results in microbial "footprints" which, based on lectin binding assays, consist of mannose, glucose and fucose containing compounds. (ufz.de)
  • it occurs when mannose-binding lectin (MBL), a serum protein, binds to mannose, fucose, or N -acetylglucosamine groups on bacterial cell walls, yeast walls, or viruses. (msdmanuals.com)
  • Investigation of the Binding Affinity of a Broad Array of l-Fucosides with Six Fucose-Specific Lectins of Bacterial and Fungal Origin , MOLECULES 24: (12) pp. 2262-2279. (doktori.hu)
  • For example, MBL has been shown to bind to: yeasts such as Candida albicans viruses such as HIV and influenza A many bacteria, including Salmonella and Streptococci parasites like Leishmania SARS-CoV-2 MBL in the blood is complexed with (bound to) a serine protease called MASP (MBL-associated serine protease). (wikipedia.org)
  • TGF-β signaling is initiated when the ligand binds to type II serine/threonine kinase receptor (TGFBR2), which then phosphorylates and activates type I serine/threonine kinase receptor (TGFBR1) [ 13 ]. (degruyter.com)
  • Furthermore, differential binding was observed also to known endogenous ligands C1q, mannose-binding lectin, and secretory IgA. (researchgate.net)
  • Endogenous lectins and glycans are critical signals in the resolution of cell death. (nature.com)
  • MBL belongs to the class of collectins in the C-type lectin superfamily, whose function appears to be pattern recognition in the first line of defense in the pre-immune host. (wikipedia.org)
  • Mannose-binding lectin (MBL), a complement factor of innate immunity, has been hypothesized to play a role in the clearance of pathogenic autoantibodies from the circulation, in particular those autoantibodies that lack galactose sugar residues. (eur.nl)
  • BACKGROUND: Mannose-binding lectin (MBL) is a key component of innate immunity. (ed.ac.uk)
  • Intracellular lectins and glycan-modifying enzymes mediate autophagy and control host immunity and inflammation. (nature.com)
  • The classical, lectin, and alternative pathways converge into a final common pathway when C3 convertase (C3 con) cleaves C3 into C3a and C3b. (msdmanuals.com)
  • 2008). Genetic Heterogeneity of Lectin Complement Activation Pathway Defects See also LCAPD2 (613791), caused by variation in the MASP2 gene (605102) on chromosome 1p36, and LCAPD3 (613860), caused by variation in the FCN3 gene (604973) on chromosome 1p36. (nih.gov)
  • ATR- FTIR , molecular docking , and dynamic simulation between SARS-CoV-2 S and either lectins indicated molecular interactions with predicted binding energies of -85.4 and -72.0 Kcal/Mol, respectively. (bvsalud.org)
  • Two decades later, pioneering studies suggested that lectin-like molecules constitutively expressed on the surface of macrophages can selectively recognize changes on glycans decorating the surface of apoptotic thymocytes, 4 , 5 although these studies likewise did not provide substantial insight into the mechanisms by which lectin-glycan interactions regulate cell death. (nature.com)
  • We discuss here the contribution of glycan-lectin interactions to the initiation, execution and resolution of apoptosis and their emerging roles in other cell death programs including autophagy. (nature.com)
  • Studies on carbohydrate-lectin interactions. (doktori.hu)
  • Mannose-binding lectin gene polymorphisms in a cohort study of ANCA-associated small vessel vasculitis. (ox.ac.uk)
  • Here, we evaluated the in vitro anti- SARS-CoV-2 activity of two mannose-binding lectins isolated from the Brazilian plants Canavalia brasiliensis and Dioclea violacea (ConBR and DVL). (bvsalud.org)
  • A Bacterial Mannose Binding Lectin as a Tool for the Enrichment of C- and O-Mannosylated Peptides. (mpg.de)
  • 7 It is possible that these major histocompatibility complexes bind antigens in such a way that they increase the likelihood of T-cells mounting an immune response to self-antigens. (lww.com)
  • Evaluation of Mannose Binding Lectin Gene Variants in Pediatric Influenza Virus-Related Critical Illness. (escholarship.org)
  • Therefore, carbohydrate binding agents may represent potential candidates to abrogate virus infection . (bvsalud.org)
  • OBJECTIVE: To investigate whether single nucleotide polymorphisms (SNPs) within the mannose-binding lectin (MBL) gene are associated with small vessel vasculitis (SVV) and are a risk factor for intercurrent infection, as described previously in other autoimmune diseases. (ox.ac.uk)
  • Is Plasma Level of Mannose Binding Lectin Associated With Reproductive Failure? (who.int)
  • The aim of this study was to investigate the role of ArtinM lectin in AFB1-induced hepatocarcinogenesis in rats. (usp.br)
  • Although lectins were already known because of their ability to agglutinate red blood cells, 3 the involvement of lectins and glycans in PCD had not been elucidated. (nature.com)
  • The presence of mannose resulted in the complete lack of anti- SARS-CoV-2 activity by ConBR and DVL, recovering virus titers. (bvsalud.org)
  • The emergence of functional studies on animal lectins during the 1990s has provided the appropriate framework to better understand their roles in cell death. (nature.com)
  • Understanding the function of lectin-glycan recognition systems in cell death will facilitate the implementation of novel therapeutic strategies aimed at controlling unbalanced cell proliferation and survival in several pathologic conditions. (nature.com)
  • The C4b fragments can then bind to the surface of the bacterium, and initiate the formation of a C3-convertase. (wikipedia.org)
  • C-reactive protein, Immunoglobulins and mannose binding lectin (MBL) levels were measured and correlated to vaccine response. (manchester.ac.uk)
  • Wistar rats were gavage-poisoned with 400 ?g AFB1 per kilogram of ration fed for three months, while the AFB1 + ArtinM group received three subcutaneous doses of the lectin (50 ?g per kilogram of animal weight per dose) 45, 60 and 75 days after the start of the experiment. (usp.br)

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