Search results

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.It has recently been shown that SARS is caused by a human coronavirus. Human coronaviruses are the major cause of upper respiratory tract illness in humans, such as the common cold. Coronaviruses are positive-stranded RNA viruses, featuring the largest viral RNA genomes known to date (27-31 kb). The first step in coronavirus infection is binding of the viral spike protein, a 139-kDa protein, to certain receptors on host cells. The spike protein is the main surface antigen of the coronavirus. The most prominent protein in the culture supernatants infected with SARS virus is a 46 kDa nucleocapsid protein. This suggests that the nucleocapsid protein is a major immunogen that may be useful for early diagnostics.

Borrelia belongs to a genus of bacteria of the spirochete phylum. Borrelia causes borreliosis, which is a zoonotic, vector-borne disease transmitted mainly by ticks and some by lice, depending on the species. Of the 36 known species of Borrelia, 12 are distinguished to cause Lyme disease or borreliosis and are transmitted by ticks. The main Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii. The Borrelia genus members have a linear chromosome which is about 900 kbp in length as well as an excess of both linear and circular plasmids in the 5-220 kbp size range. The plasmids are atypical, as compared to most bacterial plasmids, since they contain many paralogous sequences, a large number of pseudogenes and, in some cases, essential genes. Moreover, a number of the plasmids have features suggesting that they are prophages.

Inositol oxygenase is a non-heme di-iron enzyme which oxidizes myo-inositol to glucuronic acid. In addition, inositol oxygenase oxidizes the less abundant chiro isomer of inositol. MIOX enzyme is a component of the only known pathway for the catabolism of inositol in humans. MIOX is expressed mostly in the kidneys. Reduction of Inositol Oxygenase and accumulation of polyols, such as inositol and xylitol, have been implicated as contributing factors in complications linked with diabetes.

IVD is a mitochondrial matrix enzyme that is part of the cyl-CoA dehydrogenase family which catalyzes the third step in leucine catabolism. The genetic deficiency of IVD leads to a buildup of isovaleric acid, which is toxic to the central nervous system and results in isovaleric acidemia. IVD is a homotetrameric flavoenzyme which catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA.

Defensins are cationic peptides with a large spectrum of antimicrobial activity that comprise an important arm of the innate immune system. The Alpha defensins are differentiated from the Beta-defensins by the pairing of their 3 disulfide bonds.
4 human Beta-defensins have been identified to date; BD-1, BD-2, BD-3 and BD-4.
Beta-defensins are expressed on some leukocytes and at epithelial surfaces.
In addition to their direct antimicrobial activities, they are chemoattractant towards immature dendritic cells and memory T cells. The beta-defensin proteins are expressed as the C-terminal portion of precursors and are released by proteolytic cleavage of a signal sequence and, in the case of BD-1 (36 a.a.), a propeptide region. Beta-defensins contain a six-cysteine motif that forms three intra-molecular disulfide bonds. Beta-Defensins are 3-5 kDa peptides ranging in size from 33-47 amino acid residues.

Angiopoietin-related protein 7 (ANGPTL7), belongs to the angiopoietin-like family of molecules. ANGPTL7 is expressed in the corneal stroma, trabecular meshwork, and sclera. ANGPTL7 production is up-regulated in trabecular meshwork cells by glucocorticoids and TGF-Beta and in cartilage by TNF-alpha.

Coproporphyrinogen Oxidase (CPOX) which is localized to the internal membrane space of erythrocytes takes part in the 6th phase of heme biosynthesis. CPOX catalyzes the oxidative decarboxylation of propionic acid side chains of rings A and B of coproporphyrinogen III. Mutations in human CPOX gene forecast the clinical result of the disease, with either hepatic hereditary coproporphyria or hematological manifestations of erythropoietic harderoporphyria.

BLVRB (EC 1.3.1.24) catalyzes electron transfer from reduced pyridine nucleotides to flavins as well as methylene blue, pyrroloquinoline quinone, riboflavin, or methemoglobin. BLVRB is involved in protecting cells from oxidative damage or in regulating iron metabolism. BLVRB converts biliverdin to bilirubin in the liver, converting a double-bond between the second and third pyrrole ring into a single-bond. BLVRB plays a role as in human erythrocytic heme catabolic pathway and most mammalian species. Biliverdin reductase is abundantly expressed in kidney, spleen, liver and brain as well as at lower levels in the thymus and minimal levels being detected in testis.

CD163 is an acute phase-regulated receptor which participates in the removal and endocytosis of hemoglobin/haptoglobin complexes by macrophages and thus keeps tissues from free hemoglobin-mediated oxidative damage. Furthermore, CD163 partakes in the uptake and recycling of iron, through endocytosis of hemoglobin/haptoglobin and ensuing breakdown of heme. In addition, CD163 binds hemoglobin/haptoglobin complexes in a calcium-dependent and pH-dependent way. CD163 demonstrates greater affinity for complexes of hemoglobin and multimeric haptoglobin of HP-1F phenotype than for complexes of hemoglobin and dimeric haptoglobin of HP-1S phenotype. Moreover, CD163 stimulates a cascade of intracellular signals which involves tyrosine kinase-dependent calcium recruitment, inositol triphosphate formation and secretion of IL-6 & CSF-1.

FIAF (fasting-induced adipose factor) a.k.a ANGPTL4 or PGAR or HFARP is an adipocytokine up-regulated by fasting, by peroxisome proliferator-activated receptor agonists, and by hypoxia. ANGPTL4 is found in human and mouse blood plasma both as a native protein and in a truncated form. In human white adipose tissue and SGBS adipocytes, only the native form of ANGPTL4 could be detected, whereas in mice the differentiation of mouse 3T3-L1 adipocytes is associated with the production of truncated ANGPTL4. However, the truncated ANGPTL4 is produced by human liver. In human blood plasma FIAF is mainly presented in a truncated form (FIAF-S2), whose levels treatment increases (as shown by experimental data). There is an inter individual variation in ANGPTL4 levels of both the truncated and the native form, however those levels were not influenced by prolonged semistarvation and are not associated with body mass index.

CD55 belongs to the RCA (regulators of complement activation) family characterized by 4-30 SCRs (short consensus repeats) in their plasma-exposed regions. CD55 is widely expressed in malignant tumors and nevertheless functions as an inhibitor of the complement system.

Activating transcription factor 4 (ATF4) is a member of a family of DNA-binding proteins which includes the AP-1 family of transcription factors, cAMP-response element binding proteins and CREB-like proteins. The ATF4 gene encodes a transcription factor which was initially identified as a widely expressed mammalian DNA binding protein that could bind a tax-responsive enhancer element in the LTR of HTLV-1.

CD207 (C-type lectin domain family 4 member K) is expressed in Langerhans cells which are immature dendritic cells of the epidermis and mucosa. Moreover, CD207 is expressed in several other dendritic cell types including dermal CD103+ DCs and splenic CD8+ DCs. Langerin is localized in the Birbeck granules, the organelles present in the cytoplasm of Langerhans cells and comprised of superimposed and zippered membranes. CD207 is a C-type lectin with mannose binding specificity, and it has been suggested that mannose binding by the CD207 protein leads to internalization of antigen into Birbeck granules thus providing access to a nonclassical antigen-processing pathway.

CD79B is a 36 kDa trans membrane glycoprotein belonging to the immunoglobulin superfamily. Heterodimers of CD79A and CD79B connect with a membrane attached immunoglobulin on the B cell surface to create the B cell antigen receptor complex (BCR). CD79A and CD79B are essential for BCR-mediated signaling and subsequently for the development and activation of B lineage cells.

Midkine (MK) is the product of a retinoic acid responsive gene, MK, and is a member of a family of heparin binding factors. It contains 121 amino acid residues including 10 conserved cysteine residues, all of which appear to be disulphide linked.
Midkine is expressed during embryogenesis, showing an expression pattern that suggests functions in neurogenesis, cell migration, secondary organogenetic induction, and mesoderm-epithelial interaction.
The widespread downregulation of MK in the adult human is reverted in a number of cancers, in which polypeptides are able to act as both transforming growth factors and promoters of angiogenesis.
Midkine (MK), induces chemotaxis of human neutrophils and was found to trigger mobilization of intracellular calcium of these cells.
Midkine induces histamine release from rat peritoneal mast cells with a rapid response in a dose dependent manner.
Midkine is also a potent stimulator of collagen and glycosaminoglycan synthesis.

Thrombopoietin is a glycoprotein hormone produced mainly by the liver and the kidney that regulates the production of platelets by the bone marrow. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that fragment into large numbers of platelets.

CD27 belongs to the TNF-receptor superfamily. CD27 is necessary for initiation and long-term maintenance of T cell immunity. CD27 binds to ligand CD70, and has a crucial role in regulating B-cell activation and immunoglobulin synthesis. The CD27 receptor transduces signals which result in the activation of NF-kappaB and MAPK8/JNK. Adaptor proteins TRAF2 and TRAF5 mediate the signaling process of CD27. CD27-binding protein (SIVA), which is a proapoptotic protein, can bind to the CD27 receptor and is believed to have a significant role in the apoptosis induced by CD27.

CMRF35-like molecule 2 precursor (CD300E) is a member of the CD300 family. CD300E is a 205 amino acid single-pass type I membrane protein which contains one Ig-like V-type (immunoglobulin-like) domain. While interacting with DAP12, CD300E probably performs as an activating receptor. CD300E is present on the surface of mature hematopoietic cells of the monocyte & myeloid lineages.

AK4 belongs to the adenylate kinase family of enzymes. AK4 protein is restricted to the mitochondrial matrix. Adenylate kinases regulate the adenine and guanine nucleotide structures in a cell by catalyzing the reversible transfer of phosphate group among these nucleotides. Hereditary mutations which cause AK4 deficiencies in erythrocytes have been associated to hemolytic anemia.

Borrelia belongs to a genus of bacteria of the spirochete phylum. Borrelia causes borreliosis, which is a zoonotic, vector-borne disease transmitted mainly by ticks and some by lice, depending on the species. Of the 36 known species of Borrelia, 12 are distinguished to cause Lyme disease or borreliosis and are transmitted by ticks. The main Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii. The Borrelia genus members have a linear chromosome which is about 900 kbp in length as well as an excess of both linear and circular plasmids in the 5-220 kbp size range. The plasmids are atypical, as compared to most bacterial plasmids, since they contain many paralogous sequences, a large number of pseudogenes and, in some cases, essential genes. Moreover, a number of the plasmids have features suggesting that they are prophages.

Semaphorin-4D (CD100) is a member of the semaphorin family containing 1 Ig-like C2-type domain, 1 PSI domain and 1 Sema domain. CD100 is the cell surface receptor forPLXN1B and PLXNB2 which plays a central role in cell-cell signaling. CD100 stimulates the migration of cerebellar granule cells and of endothelial cells, regulates dendrite and axon branching and morphogenesis. In addition, CD100 has a role in the immune system; it promotes signaling via SRC and PTK2B/PYK2, which subsequently mediates activation of phosphatidylinositol 3-kinase and of the AKT1 signaling cascade.

CD99, or MIC2 gene product, or E2 antigen is expressed on the cell membrane of some lymphocytes, cortical thymocytes, and granulosa cells of the ovary. The antigen is also expressed by most pancreatic islet cells, Sertoli cells of the testis, and some endothelial cells. Mature granulocytes express very little or no CD99. MIC2 is strongly expressed on Ewing’s sarcoma cells and primitive peripheral neuroectodermal tumors.