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SPARC protein, or secreted protein acidic and rich in cysteine, or osteonectin or basement-membrane protein 40 is a protein that is coded by the SPARC gene in humans. It is a glycoprotein located in bones, that binds to calcium. The osteonectin is secreted from osteoblasts cells when boas are formed, mineralized and promotes the formation and creation of mineral crystals. Asides from calcium, it has been shown that this protein can also bind to collagen.

Secreted Protein Acidic & Rich in Cysteine (SPARC) protein is coded by the SPARC gene in humans. SPARC is a glycoprotein located in bones that binds to calcium. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, mainly in areas of tissue morphogenesis and remodelling. Asides from calcium, SPARC can also bind to collagen.

SPARC, an acronym for “secreted protein, acidic and rich in cysteine”, is also known as osteonectin or BM-40. It is the founding member of a family of secreted matricellular proteins with similar domain structure. The 303 amino acid, 43 kDa protein contains a 17 aa signal sequence, an N-terminal acidic region that binds calcium, a follistatin domain containing Kazal-like sequences, and a C-terminal extracellular calcium (EC) binding domain with two EF-hand motifs. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, especially in areas of tissue morphogenesis and remodeling. SPARC shows context-specific effects, but generally inhibits adhesion, spreading and proliferation, and promotes collagen matrix formation. For endothelial cells, SPARC disrupts focal adhesions and binds and sequesters PDGF and VEGF. SPARC is abundantly expressed in bone, where it promotes osteoblast differentiation and inhibits adipogenesis.

SPARC, an acronym for “secreted protein, acidic and rich in cysteine”, is also known as osteonectin or BM-40. It is the founding member of a family of secreted matricellular proteins with similar domain structure. The 303 amino acid, 43 kDa protein contains a 17 aa signal sequence, an N-terminal acidic region that binds calcium, a follistatin domain containing Kazal-like sequences, and a C-terminal extracellular calcium (EC) binding domain with two EF-hand motifs. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, especially in areas of tissue morphogenesis and remodeling. SPARC shows context-specific effects, but generally inhibits adhesion, spreading and proliferation, and promotes collagen matrix formation. For endothelial cells, SPARC disrupts focal adhesions and binds and sequesters PDGF and VEGF. SPARC is abundantly expressed in bone, where it promotes osteoblast differentiation and inhibits adipogenesis.

SPARC-like protein 1 or SPARC1 is an anti-adhesive protein with a similarity to the SPARC protein’s structure. SPARC1 is highly expressed in several tissues such as brain, lungs, kidney, heart, although it is not found in the liver tissue. The protein inhibits spreading or adhesion of many substrates and is considered to lead to antiadhesive signaling that stops neuronal migration, that occurs during development or as a trauma response, consistent with production by glial and neuronal cells.

Testican-3 (Spock3) is a nervous system-expressed heparan sulfate proteoglycan belonging to a subgroup of the BM-40/SPARC/osteonectin family, whose role of in brain development is unclear. Spock3 inhibits the processing of pro-matrix metalloproteinase 2(MMP-2) by MT1-MMP and MT3-MMP. Spock3 is mostly confined to the developmental stage of the brain.

Protein A is a cell wall component produced by several strains of Staphylococcus aureus. The recombinant Protein A is genetically engineered protein and holds 5 IgG-binding regions of protein A. Recombinant Protein A functions basically the same as native Protein A and is perfect for purification of polyclonal or monoclonal IgG antibodies. Protein A binds to human IgG1, IgG2 and IgG4, mouse IgG2a, IgG2b and IgG3 and rat IgG2c. Protein A also binds to total IgG from rabbit, pig, dog, cat, and guinea pig.

Decorin (DCN) is a small cellular or pericellular matrix proteoglycan which is closely related in structure to biglycan protein. Decorin is a secreted protein which binds to collagen and fibronectin in extracellular matrix. Decorin appears in different glycoforms, substituted with chondroitin sulfate or dermatan sulfate consistent with the original tissue. DCN contains one attached glycosaminoglycan chain. Decorin influences the rate of fibril formation. Decorin is capable of suppressing the growth of various tumor cell lines. DCN gene defects cause corneal dystrophy. The DCN gene is a candidate gene for Marfan syndrome.

Sperm Associated Antigen 7 (SPAG7) is comprised of 1 R3H domain. SPAG7 is detected in fetal brain and localized in the nucleus.

Protein A is a cell wall component produced by several strains of Staphylococcus aureus. The recombinant Protein A is genetically engineered protein and holds 5 IgG-binding regions of protein A. Recombinant Protein A functions basically the same as native Protein A and is perfect for purification of polyclonal or monoclonal IgG antibodies. Protein A binds to human IgG1, IgG2 and IgG4, mouse IgG2a, IgG2b and IgG3 and rat IgG2c. Protein A also binds to total IgG from rabbit, pig, dog, cat, and guinea pig.

PMSG Hormone is a well know used hormone together with progestogen to increase ovulation just before to artificial insemination. PMSG hormone is a placental glycoprotein produced from the serum of pregnant mares. PMSG comprises of an alfa subunit and a beta subunit. PMSG hormone is secreted from endometrial cups within the pregnant mare uterus aging from 40 to 130 days into their maturation, and once extracted, it can been used to promote artificially estrus in female animals. These assemblies produce PMSG hormone to induce mare's ovarian and repsouctive structures. PMSG can induce the growth of follicles by ovaries and results in ovulatation. PMSG hormone has an about a 4 day half-life of bioactivity in species other than horses. The extended biological activity can cause ovarian stimulation and ovulation. However, PMSG use alone often causes cystic ovarian disease because of the unrestrained ovarian stimulation and due to the sugar molecules which decrease clearance of the hormone. PMSG is more likely to be used than other pituitary hormones due to the extended circulatory half-life. PMSG solely exhibits luteinizing hormone like activity, however in other animal classes it has FSH & LH like activity.

Protein A is a cell wall component produced by several strains of Staphylococcus aureus. The recombinant Protein A is genetically engineered protein and holds 5 IgG-binding regions of protein A. Recombinant Protein A functions basically the same as native Protein A and is perfect for purification of polyclonal or monoclonal IgG antibodies. Protein A binds to human IgG1, IgG2 and IgG4, mouse IgG2a, IgG2b and IgG3 and rat IgG2c. Protein A also binds to total IgG from rabbit, pig, dog, cat, and guinea pig.

ARPC5 is a 151 amino acid subunit of the Arp2/3 complex. ARPC5 is believed to have a role in maintaining the integrity of Arp2/3. ARPC5 is a substrate for MAPKAPK-2 which, via phosphorylation of ARPC5, may participate in Arp2/3 regulatory functions and remodeling of the Actin cytoskeleton.

Decorin (DCN) is a small cellular or pericellular matrix proteoglycan which is closely related in structure to biglycan protein. Decorin is a secreted protein which binds to collagen and fibronectin in extracellular matrix. Decorin appears in different glycoforms, substituted with chondroitin sulfate or dermatan sulfate consistent with the original tissue. DCN contains one attached glycosaminoglycan chain. Decorin influences the rate of fibril formation. Decorin is capable of suppressing the growth of various tumor cell lines. DCN gene defects cause corneal dystrophy. The DCN gene is a candidate gene for Marfan syndrome.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

SMARCA4 belongs to the SWI/SNF family of proteins and is similar to the brahma protein of Drosophila. Proteins in this family have helicase and ATPase activities and are considered to regulate transcription ofcertain genes by altering the chromatin structure around those genes. SMARCA4 is part of the large ATP-dependent chromatin remodeling complex SNF/SWI, which is essential for transcriptional activation of genesnormally repressed by chromatin. In addition, SMARCA4 is able to bind BRCA1, as well as regulating the expression ofthe tumorigenic protein CD44. Moreover, mutations in SMARCA4 cause rhabdoid tumor predisposition syndrome type 2.

SPA17 is a protein present at the cell surface. SPA17 was characterized by its participation in the binding of sperm to the zona pellucida of the oocyte. The central portion of SPA17 has carbohydrate binding motifs and likely takes part in cell-cell adhesion functions such as immune cell migration and metastasis.

HSPA9 is part of the heat shock protein 70 family which contains both heat-inducible and constitutively expressed members that are also called heat-shock cognate proteins. HSPA9 encodes a heat-shock cognate protein that is involved in the control of cell proliferation and acts as a chaperone. HSPA9 was restricted to chromosome 5, band q31, a region that is often deleted in myeloid leukemias and myelodysplasia (MDS), making it a candidate tumor suppressor gene, which is consistent with the biological function of its murine homologue. HSPA9 supresses nuclear translocation, transcriptional activation, and control of centrosome-duplication functions of p53.

PLAUR is one of 2 activators which convert the extracellular zymogen plasminogen to plasmin, a serine protease involved in a various normal and pathological processes that require cell migration and/or tissue destruction. PLAUR protein is synthesized and released from cells as a single-chain proenzyme with narrow enzymatic activity and is converted to an active two-chain disulfide-linked active enzyme by plasmin and other specific proteinases.

The peroxisome proliferator activated receptors (PPARs) are ligandactivated transcription factors within the nuclear receptor superfamily, which play important roles in adipogenesis, glucose homeostasis andinflammation. Three different isotypes can be distinguished; alpha, beta and gamma. PPARg, is mainly expressed in adipose tissue and to lesser extent in colon, the immune system and the retina. Whereas PPARg operates in the catabolism of fatty acids in the liver, PPARg influences the storage of fatty acids in the adipose tissue and plays a role in adipocyte differentiation. PPARg binds to DNA as a heterodimer with retinoid X receptor (RXR), activating expression of target genes after binding ligand.

SPRY domain-containing SOCS box protein 1 (SPSB1) belongs to the SOCS box protein subfamily. SPSB1 includes a central SPRY domain and a C-terminal SOCS box. Even though, some of the SOCS protein subfamilies function as adaptors for a large family of ubiquitin-protein isopeptide ligases to regulate certain signaling pathways, the function of the SSB subfamily remains to be determined. SPSB1 may have an imperative role in enhancing the HGF-induced Erk-Elk-1-SRE pathway. SPSB1 overexpression exhibited no effect on the basal level or epidermal growth factor-induced SRE-luciferase activity.

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.

The somatomedins, or insulin-like growth factors (IGFs), comprise a family of peptides that play important roles in mammalian growth and development. IGF1 mediates many of the growth-promoting effects of growth hormone (GH; MIM 139250). Early studies showed that growth hormone did not directly stimulate the incorporation of sulfate into cartilage, but rather acted through a serum factor, termed 'sulfation factor,' which later became known as 'somatomedin' (Daughaday et al., 1972). Three main somatomedins have been characterized: somatomedin C (IGF1), somatomedin A (IGF2; MIM 147470), and somatomedin B (MIM 193190) (Rotwein, 1986; Rosenfeld, 2003).

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.