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B cell-activating factor (BAFF) enhances B-cell survival in vitro and is a regulator of the peripheral B-cell population. Overexpression of Baff in mice results in mature B-cell hyperplasia and symptoms of systemic lupus erythematosus (SLE). Also, some SLE patients have increased levels of BAFF in serum. Therefore, it has been proposed that abnormally high levels of BAFF may contribute to the pathogenesis of autoimmune diseases by enhancing the survival of autoreactive B cells. The protein encoded by this gene is a receptor for BAFF and is a type III transmembrane protein containing a single extracellular cysteine-rich domain. It is thought that this receptor is the principal receptor required for BAFF-mediated mature B-cell survival.

Chromogranin-A Isoform 1 Preproprotein or CHGA is part of the neuroendocrine secretory proteins of the chromogranin/secretogranin family. CHGA is a precursor of numerus enzymes such as pancreastatin, catestatin, vasostatin-1,vasostatin-2, and parastatin. The protein acts as a negative regulator the neuroendocrine activity of autocrine or nearby cells (paracrine). CHGA causes further production of secretory granules that contains insulin in pancreatic islet beta cells.

Melanoma-associated antigen D1 (MAGED1) belongs to the melanoma antigen gene (MAGE) family and expressed in virtually all normal adult tissues. MAGED1 is involved in the p75 neurotrophin receptor mediated programmed cell death pathway. MAGED1 is involved in Prader-Willi syndrome including hyperphagia, repetitive and compulsive behaviors, and cognitive impairment. MAGED1 is involved in the apoptotic response following NGF (nerve growth factor) binding in neuronal cells. MAGED1 hinders cell cycle progression, and facilitates NGFR-mediated apoptosis. MAGED1 functions as a regulator of the function of DLX family members. MAGED1 has a role in the circadian rythm regulation.

RANKL binds to tnfrsf11b/opg and to tnfrsf11a/rank. Osteoclast differentiation and activation factor. Augments the ability of dendritic cells to stimulate naive t-cell proliferation. May be an important regulator of interactions between t-cells and dendritic cells and may play a role in the regulation of the t-cell-dependent immune response. sRANKL may also play an important role in enhanced bone-resorption in humoral hypercalcemia of malignancy. By injecting soluble RANKL, novel osteopenia model mice were established in only 50 hours. Degree of bone loss can be controlled by changing doses of sRANKL. RANKL can be used in establishing osteopenia model for in vivo screening of drugs for osteoporosis, determination of effect and mechanism, evaluation of bone anabolic drugs.

CALN1 is highly similar to the calcium-binding proteins of the calmodulin family. The CALN1 protein contains two EF-hand domains and potential calcium-binding sites. Also, CALN1 negatively regulates Golgi-to-plasma membrane trafficking by interacting with PI4KB and inhibiting its activity. CALN1 has a role in the physiology of neurons and is potentially significant in memory and learning.

Crystallins are the main structural proteins of the vertebrate eye lens, where they maintain the transparency and refractive index of the lens. Crystallins are divided into 3 fprotein families, α, β, & γ families. Because lens central fiber cells lose their nuclei during development, these crystallins are prepared and then retained throughout life, making them extremely stable proteins. CRYBB1 is a beta basic group member and undergoes extensive cleavage at its N-terminal extension during lens maturation.

APIP catalyzes the dehydration of methylthioribulose-1-phosphate (MTRu-1-P) into 2,3-diketo-5-methylthiopentyl-1-phosphate (DK-MTP-1-P). APIP has an anti-apoptotic function and inhibits muscle ischemic impairment. APIP inhibits the cytochrome c-dependent and APAF1-mediated cell death.

FGF8 is part of the fibroblast growth factor family. FGF family members have wide mitogenic and cell survival activities, and participate in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. FGF8 supports androgen and anchorage independent growth of mammary tumor cells. FGF8 over expression increases tumor growth and angiogensis. The adult expression of FGF-8 gene is restricted to testes and ovaries. FGF8 functions as an embryonic epithelial factor. FGF8 takes part in midbrain and limb development, organogenesis, embryo gastrulation and left-right axis determination.

C3b is derived from native C3 upon cleavage with the alternative pathway C3 convertase and release of C3a. C3b is essential to the function of all 3complement pathways. Initiation of each pathway generates proteolytic enzyme complexes (C3 convertases) which binds the target surface. These enzymes cleave a peptide bond in C3 releasing the anaphylatoxin C3a and activating C3b. Most of the C3b created during complement activation. Surface-bound C3b is needed in all 3 pathways for effective activation of C5 and formation of C5b-9 complexes which lyse the target cell membrane. Surface-bound C3b and its breakdown products iC3b and C3d are identifyid by various receptors on lymphoid and phagocytic cells which use the C3b ligand to stimulate antigen presentation to cells of the adaptive immune system. It results in an expansion of target-specific B-cell and T-cell populations.

Complement Factor B, also known as CFB, encodes complement factor B which is a component of the alternative pathway of complement activation. Factor B circulates in the blood as a single chain polypeptide. Once the alternative pathway is activated it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb. The active subunit Bb is a serine protease which connects with C3b to form the alternative pathway C3 convertase. Also, Bb is involved in the proliferation of preactivated B lymphocytes, while Ba inhibits their proliferation.

GDF15 is part of the TGF-Beta superfamily which is involved in regulating inflammatory and apoptotic pathways in injured tissues and throughout disease processes. GDF15 is most abundant in the liver. Its expression in liver can be considerably up-regulated in during injury of organs such as liver, kidney, heart and lung. GDF-15 promotes proliferation or growth arrest and differentiation due to differences in cellular differentiation. GDF15 prevents apoptosis in cerebellar granule neurons by activating Akt and inhibiting endogenously active ERK. GDF15 is a novel autocrine/endocrine factor that antagonizes the hypertrophic response and loss of ventricular performance.

Exenatide Derived from the saliva of the gila monster, is a 39 amino acid peptide that mimics the GLP-1 incretin, an insulin secretagogue with glucoregulatory effects. Typical responses to exenatide include improvements in the initial rapid release of endogenous insulin, suppression of glucagon release by the pancreas, regulation of gastric empyting, and reduced appetite - all of which function to lower blood glucose. Exenatide is self-regulating in that it lowers blood sugar when levels are elevated but does not continue to lower blood sugar when levels return to normal, unlike with sulfonylureas or insulins.

Hepatitis B virus x interacting protein (HBXIP) forms a complex with the C-terminus of hepatitis B virus X (HBX) protein. HBXIP negatively regulates HBX activity and changes the replicative life cycle of the virus. Furthermore, HBXIP is involved in bipolar spindle formation and regulates centrosome dynamics and cytokinesis in cells, possibly due to interaction with Dynein light chain. HBXIP is highly expressed in the skeletal and cardiac muscle, followed by pancreas, kidney, liver, brain, placenta and lung. HBXIP has elevated levels in both cancerous and non-cancerous liver tissue of patients with chronic HBV infection compared with hepatic tissue without HBV infection.

SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid. CXCL12 is strongly chemotactic for lymphocytes and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor.
The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.

The Defensin family are highly similar in their protein sequence and are microbicidal & cytotoxic peptides made by neutrophils. Beta Defensin-1 is an antimicrobial peptide having the resistance of epithelial surfaces to microbial colonization. Beta Defensin-1 has close proximity to Defensin Alpha-1 and has been implicated in the pathogenesis of cystic fibrosis.
Skin of patients having atopic dermatitis patients and mycosis fungoides (non-lesional and lesional) show lower human Beta Defensin-1 mRNA expression and higher human Beta Defensin-2 and human Beta Defensin-3 mRNA expression.
Beta Defensin is highly expressed by epithelial cells.
Beta-defensin 1 may play a role in the pathogenesis of severe sepsis.

Gastroenteritis which has been identified as caused by Yersinia Enterocolitica has been discovered by virulent isolates of the bacteria. During infection, pores are being formed in the presence of adapter protein Yersiniosis. YopB's Interaction with the target membrane to form pores enables the entrance of YopE effectors to the cytoplasmic space of the host’s cell.

A human infecting coronavirus (viral pneumonia) called 2019 novel coronavirus, 2019-nCoV was found in the fish market at the city of Wuhan, Hubei province of China on December 2019.

The 2019-nCoV shares an 87% identity to the 2 bat-derived severe acute respiratory syndrome 2018 SARS-CoV-2 located in Zhoushan of eastern China. 2019-nCoV has an analogous receptor-BD-structure to that of 2018 SARS-CoV, even though there is a.a. diversity so thus the 2019-nCoV might bind to ACE2 receptor protein (angiotensin-converting enzyme 2) in humans.

While bats are possibly the host of 2019-nCoV, researchers suspect that animal from the ocean sold at the seafood market was an intermediate host. RSCU analysis proposes that the 2019-nCoV is a recombinant within the viral spike glycoprotein between the bat coronavirus and an unknown coronavirus.

p59-Fyn is a member of the protein-tyrosine kinase oncogene family. p59fyn is a membrane-associated non-receptor protein tyrosine kinase that belongs to the Src-family of kinases. p59-Fyn encodes a membrane-associated tyrosine kinase which is implicated in the control of cell growth. p59-Fyn associates with the p85 subunit of phosphatidylinositol 3-kinase and interacts with the fyn-binding protein. The unique N-terminal domain of p59fyn interacts with the CD3 and eta chains of the TcR. p59fyn can bind other proteins (p82 and p116) through its SH2 and SH3 domains, which may act as substrates or regulators of fyn activity. p59fyn is highly expressed in brain suggesting that it may have a role in the sensory nervous network and in myelination at early stages of CNS formation. Distinct isoforms exist due to alternative splicing.

Keratin 8 and 18 (K8/18) are the major components of intermediate filament (IF) proteins of simple or single-layered epithelia.

Human Retinol Binding Protein, also known as RBP, is responsible for transporting and binding vitamin A. Human RBP has a binding site for 1 molecule of retinol and circulates in the plasma together with prealbumin as a protein complex. The prealbumin binding prevents greater glomerular losses of the human RBP. Only the retinol-free form of the RBP, which has no affinity for prealbumin, undergoes glomerular filtration unhindered as a result of its low Mw. Human RBP is re-absorbed by the tubular cells and catabolized there.

Streptolysin-O is a sulfhydryl-activated toxin which causes cytolysis by forming pores in cholesterol containing host membranes. After binding to target membranes, the Streptolysin-O protein undergoes a major conformation change, leading to its insertion in the host membrane and creation of an oligomeric pore complex. Cholesterol may be needed for binding to host membranes, membrane insertion and pore formation. Streptolysin-O can be reversibly inactivated by oxidation.

Ro 60 kDa autoantigen is an RNA-binding protein that binds to several small cytoplasmic RNA molecules known as Y RNAs. SSA2 may stabilize these RNAs from degradation. Sera taken from patients with Systemic Lupus Erythematosus (SLE) often contains antibodies that react with the normal cellular SSA2 protein as if this antigen was foreign.

Listeriolysin O (aka LLO) is a hemolysin produced by Listeria monocytogenes bacteria, the pathogen responsible for causing listeriosis. The toxin may be regarded as a virulence factor, since it is crucial for the virulence of L. monocytogenes. LLO is a single polypeptide protein encoded by the hlyA gene and composed of 529 residues. LLO is a thiol-activated cholesterol-dependent pore forming toxin protein; therefore, it is activated by reducing agents and inhibited by oxidizing agents. Still, LLO differs from other thiol-activated toxins, as its cytolytic activity is maximized at a pH of 5.5. Inside the acidic phagosomes (average pH ~ 5.9) of cells that have phagocytosed L. monocytogenes, LLO is selectively activated by maximizing activity at a pH of 5.5. Following the phagosome lysis by LLO, the bacterium breaks out into the cytosol, where it is able to grow intracellularly, and the toxin has reduced activity in the more basic cytosol. Thus, LLO permits L. monocytogenes to break out from the phagosomes into the cytosol without harming the plasma membrane of the infected cell, which allows the bacteria to live intracellularly, where they are sheltered from extracellular immune system factors such as the complement system and antibodies. LLO also brings about dephosphorylation of histone H3 and deacetylation of histone H4 in the early phases of infection, before entry of L. monocytogenes into the host cell. The pore-forming activity is not implicated in causing the histone modifications. The modifications of the histones affect the down regulation of genes encoding proteins involved in the inflammatory response. Therefore, LLO may be significant in subverting the host immune response to L. monocytogenes. At its NH2-terminus it possesses a 25 residues long typical signal sequence excited during the secretion process. Moreover, in its NH2-terminus there is also a 19 amino acids PEST- like sequence that may target this toxin for degradation. The PEST-like sequence found in LLO and is considered crucial for virulence, given that mutants lacking the sequence lysed the host cell. Nevertheless, contrary to PEST's supposed role in protein degradation, evidence implies that the PEST-like sequence may control LLO production in the cytosol rather than increase degradation of LLO.

KRT20 is a member of the keratin family. The keratins are intermediate filament proteins responsible for the structural integrity of epithelial cells and are subdivided into cytokeratins and hair keratins. The type I cytokeratins consist of acidic proteins which are arranged in pairs of heterotypic keratin chains. This cytokeratin is a major cellular protein of mature enterocytes and goblet cells and is specifically expressed in the gastric and intestinal mucosa. The type I cytokeratin genes are clustered in a region of chromosome 17q12-q21.