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HBsAg is the surface antigenof the Hepatitis-B-Virus (HBV). The capsidof a virus has different surface proteins from the rest of the virus. The antigen is a protein that binds specifically on one of these surface proteins. It is commonly referred to as the Australian Antigen.

Hemopexin (or haemopexin) is a plasma protein that binds heme with the highest affinity of any known protein. Hemopexin is generally expressed in liver, and belongs to acute phase reactants, the synthesis of which is induced after inflammation. Heme is potentially very toxic because of its ability to intercalate into lipid membrane and to generate hydroxyl radicals. Hemopexin’s function of scavenging the heme released or lost by the turnover of heme proteins such as hemoglobin defends the body from the oxidative damage that free heme can cause. Additionally, hemopexin discharges its bound ligand for internalisation upon interacting with a specific receptor located on the surface of liver cells. This hemopexin function is in order to preserve the body's iron. Hemopexin’s levels in the serum are an indication of how much heme is present in the blood. Low Hemopexin levels show that there is a lot of it in the serum. For that reason, low hemopexin levels indicate that there has been consid

Entry of HSV into the host cell involves interactions of several viral glycoproteins with cell surface receptors. The virus particle is covered by an envelope which, when bound to specific receptors on the cell surface, will fuse with the cell membrane and create an opening, or pore, through which the virus enters the host cell. The sequential stages of HSV entry are analagous to those of other viruses. At first, complementary receptors on the virus and cell surface bring the two membranes into proximity. In an intermediate state, the two membranes begin to merge, forming a hemifusion state. Finally, a stable entry pore is formed through which the viral envelope contents are introduced to the host cell.

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.

Septin-3, also known as SEPT3 is a member of the septin family of GTPases. Members of this family are essential for cytokinesis. Furthermore, expression is up regulated by retinoic acid in a human teratocarcinoma cell line. The exact role of SEPT3 has not been determined yet. In addition, among its related pathways are Bacterial invasion of epithelial cells.

RARRES2 is a secreted chemotactic protein that initiates chemotaxis through the ChemR23 G protein-coupled seven-transmembrane domain ligand. RARRES2 is upregulated by the synthetic retinoid tazarotene and found in a vast variety of tissues. RARRES2 acts as an adipokine, and is truncated on both termini from the proprotein. RARRES2 is structurally related to the cathelicidin precursors, cystatin C and kininogens. RARRES2 promotes calcium mobilization and chemotaxis of immature dendritic cells and macrophages. RARRES2 is secreted as a precursor of little biological activity, which requires proteolytic cleavage of its COOH-terminal domain to be exchangeed into a potent and highly specific agonist of ChemR23. RARRES2 signals via its receptor, ChemR23 (CMKLR1), as a positive regulator of adipocyte differentiation and metabolic function. The Chemerin receptor acts as a coreceptor for SIV and some primary HIV-1 strains. The Chemerin receptor has another ligand, called tazarotene-induced gene.

SEMA3C, also known as Semaphorin 3C, is a member of the semaphorin family 3 that are grouped into 8 major classes based on phylogenetic tree analyses and structure. Class 3 have an important function after traumatic central nervous system injuries. SEMA3C regulates neuronal and non-neuronal cells associated with the traumatic injury due to their presence in the scar tissue. SEMA3C is expressed in all somatic motor neurons, in cardiac neural crest cells during development and in lung buds. The SEMA3C functions are mediated through binding to the Plexin-D1 and Neuropilin 1 or Neuropilin 2 coreceptor complex. SEMA3C activates integrins in certain cells, so besides its repulsive activities, it also acts as a chemoattractant.

Haptoglobin-Related Protein also known as HPR, is a primate-specific plasma protein related with apolipoprotein L-I (apoL-I)-containing high-density lipoprotein (HDL) particles which shown to be a part of the innate immune defense. HPR-bound hemoglobin might contribute to the biologic activity of the circulating apoL-I/Hprcontaining HDL particles. HPR is a clinically significant forecaster of recurrence of breast cancer.

SLAMF1 is a member of the immunoglobulin gene superfamily and is involved in T-cell stimulation. The SLAMF1 protein is constitutively expressed on peripheral blood memory T cells, T-cell clones, immature thymocytes, and a fraction of B cells, and is swiftly induced on naive T cells after activation. There are probably 2 modes of SLAM signaling: one in which the inhibitor SH2D1A serves as a negative regulator and another in which protein-tyrosine phosphatase 2C (PTPN11)-dependent signal transduction functions.

BRCA2 And CDKN1A Interacting Protein (BCCIP) is a nuclear protein with multiple interacting domains which remained conserved throughout the evolution. BCCIP is an important cofactor for BRCA2 in tumor suppression, and a modulator of CDK2 kinase activity via p21. BCCIP takes also part in the regulation of BRCA2 and RAD51 nuclear focus formation, doublestrand break-induced homologous recombination, and cell cycle progression.

TPRKB is a member of the CGI121/TPRKB family. TPRKB is localized to nucleus and cytoplasm and is ubiquitously expressed. TPRKB is known to cooperate with TP53RK/PRPK.

Centromere proteins are a group of proteins which form and/or mediate the function of centromeres, the central structures of chromosomes to which spindle fibers/microtubuli attach and pull the chromosomes apart in cell division. Currently, 9 centromere proteins are known and designated CENPA to CENP-I. Most of the centromere proteins are targets of autoantibodies, the anti-centromere antibodies.
CENPB is the most important of the centromeric autoantigens: it has a molecular weight of approx. 66 kDa and plays an important role in the formation of the centromeric chromatin. CENPB antibodies are present in the sera of up to 80% of patients with CREST syndrome.

TXNL4A is a member of the Dim protein family and has a vital part in pre-mRNA splicing. As a result of a failure to express early zygotic transcripts, deletion of the gene encoding TXNL4A in Schizosaccharomyces pombe results in embryonal lethality during gastrulation. Restricted to the nucleus, TXNL4A cooperates with hnRNP F, hnRNP H2, Cas-L and PQBP-1 to influence gene expression.

Transmembrane protein PRRT2 holds a proline-rich domain in its N-terminal half. PRRT2 is known to be primarily expressed in brain and spinal cord in embryonic and postnatal stages. Alterations in this gene are the cause for paroxysmal kinesigenic dyskinesia. PRRT2 mutations were found in nearly 30% of sporadic PKC patients.

NRG1 is one of 4 proteins in the neuregulin family which act on the EGFR family of receptors. NRG1 was initially identified as a 44kDa glycoprotein that interacts with the ERBB2 receptor tyrosine kinase to increase its phosphorylation on tyrosine residues. In various brain areas, NRG1 is expressed at synaptic regions and its processing can be regulated by neuronal activity. The HRG-beta3variant of NRG1, along with HRG-alpha, beta1 and beta2 variants, was identified in various normal tissues and cancer cell lines.

The retinoid X receptor (RXR) is a pleiotropic nuclear receptor transcription factor that interacts with a variety of nuclear receptor dimeric partner. RXR binds cognate response elements as a homodimer in the presence of its ligand, 9-cis retinoic acid, or as a heterodimer with other members of the nuclear hormone receptor superfamily including retinoic acid receptors (RAR), thyroid hormone receptors (TR), vitamin D receptors and peroxisome proliferators-activated receptors (PPAR). The RXR family includes three different isoforms; RXR a, b, g . Human RXR a gene is localized on 9q34.9 and encodes two major isoforms (RXR a1, RXR a2). The DNA binding domain of RXR (111-228aa) was purified by using conventional column chromatography techniques.

SERPINB5 (Maspin) is a tumor suppressor protein of the serine proteinase inhibitor family. Maspin plays a vital role in embryonic development through critical functions in cell adhesion. In addition, Maspin is present in normal breast and prostatic epithelial cells although down regulated in the particular carcinomas. SERPINB5 impedes the growth, invasion, and metastatic properties of mammary tumors as well as the invasive ability of pancreatic ductal adenocarcinoma cells. SERPINB5 being a breast tumor suppressor gene is a significant marker of the disease progression in breast neoplasms. Furthermore, high expression of maspin is linked to squamous cell carcinoma in non-small-cell lung cancer. Moreover, maspin expression has been directly linked with the biological aggressiveness of ovarian carcinoma. Maspin exhibits no serine protease inhibitory activity since it does not undergo the stressed to relaxed conformational transition typical of active serpins.

HSF2BP, also known as HSF2 binding protein links with HSF2. This interaction takes place between the trimerization domain of HSF2 and the amino terminal hydrophilic region of HSF2BP which contains two leucine zipper motifs. Therefore, HSF2BP is involved in modulating HSF2 activation.

Neuroblastoma suppressor of tumorigenicity 1 (NBL1) is a part of the evolutionarily conserved CAN (Cerberus and DAN) family of proteins, which contain a domain resembling the CTCK (C-terminal cystine knot-like) motif found in several signaling molecules. NBL1 is a is a tumor suppressor of neuroblastoma and takes part in preventing cells from entering the final stage (G1/S) of the transformation process. NBL1 is produced in small neurons of the dorsal root ganglion. The expression of NBL1 is triggered by MATH-1.

SNTN is a member of to the S-100 family. SNTN is localized solely to the bridging structure between the cell membrane and peripheral singlet microtubules that specifically exists in the narrowed distal portion of cilia. Exogenously expressed sentan displayed affinity for the membrane protrusions, and a protein-lipid binding assay discovered that sentan bounds to phosphatidylserine which indicate that sentan is the leading molecular component of the ciliary tip to link the cell membrane and peripheral singlet microtubules, making the distal portion of the cilia narrow and stiff to permit better airway approval or ovum transport.

SPG21 binds to the hydrophobic C-terminal amino acids of CD4 which take part in suppression of CD-4 dependant T cell activation. The interaction with CD4 is mediated by the noncatalytic alpha/beta hydrolase fold domain. SPG21 adapts the stimulatory activity of CD4. SPG21 is broadly expressed in diverse tissues including heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Mutations in SPG21 cause Mast syndrome, an autosomal-recessive complicated form of hereditary spastic paraplegia characterized by dementia, thin corpus callosum and white matter abnormalities.

FUBP1 is a ssDNA binding protein which stimulates expression of c-myc in undifferentiated cells and activates the far upstream element (FUSE) of c-myc. Regulation of FUSE by FUBP happens by single-strand binding of FUBP to the non-coding strand. FUBP1 performs as an ATP-dependent DNA helicase.

PMF1-BGLAP is a locus which represents naturally occurring read-through transcription between the neighboring polyamine-modulated factor 1 (PMF1) and bone gamma-carboxyglutamate Gla protein (BGLAP) genes on chromosome 1. There are multiple transcript variants encoding isoforms as a results of alternative splicing which share sequence identity with the upstream gene product, but they have a different C-termini because of frameshifts as opposed to the downstream gene coding sequence.