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Resistin, a product of the RSTN gene, is a peptide hormone belonging to the class of cysteine-rich secreted proteins (monomeric peptide contains 11 cysteine residues) referred to as the RELM family, and is also described as ADSF (Adipose Tissue-Specific Secretory Factor) or FIZZ3 (Found in Inflammatory Zone 3). Mouse resistin is expressed as a 114 amino acid prepeptide; its hydrofobic Nterminal 20 amino acid signal peptide is cleaved before its secretion. Mouse resistin circulates in blood as a homodimeric protein consisting of two 94 amino acid polypeptides, which are disulfide-linked via Cys26.
Resistin may be an important link between obesity. Mouse resistin, specifically produced and secreted by adipocyte, acts on skeletal muscle myocytes, hepatocytes and adipocytes themselves so that it reduces their sensitivity. Steppan et al. have suggested that resistin suppressed the ability to stimulate glucose uptake. They have also suggested that resistin was present at elevated levels in blood of obese mice, and was down regulated by fasting and by antidiabetic drugs. Way et al., on the other hand, have found that resistin expression is severely suppressed in obesity.
Other studies have shown that mouse resistin increases during the differentiation of adipocytes, but it also seems to inhibit adipogenesis. In contrast, the human adipogenic differentiation is likely to be associated with a down regulation of resistin gene expression.

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.

GDF15 is part of the TGF-Beta superfamily that 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.

Cartilage-associated protein (CRTAP) is a secreted protein localizing to the extracellular space which takes part in collagen post-translational modifications, extracellular fibril assembly and intracellular trafficking. CRTAP which is mainly expressed with predominant expression in articular chondrocytes is essential for efficient 3-hydroxylation of fibrillar collagen prolyl residues. Mutations in the gene encoding CRTAP might cause to autosomal recessive osteogenesis imperfecta (OI) type 7 and type 2B.

Meteorin (METRN) is involved in both glial cell differentiation and axonal network formation during neurogenesis. METRN promotes astrocyte differentiation and transforms cerebellar astrocytes into radial glia. Moreover, the METRN protein stimulates axonal extension in small and intermediate neurons of sensory ganglia by activating nearby satellite glia.

SAA1 protein is an acute phase apolipoprotein reactant which is produced mostly by hepatocytes and under regulation of inflammatory cytokines. SAA1 (Serum amyloid A1) protein is produced mainly in the liver and circulates in low levels in the blood. The SAA1 seems to have a role in the immune system. SAA1 protein levels increase in the blood and other tissues under conditions of inflammation. SAA1 may facilitate the repair of injured tissues; it also acts as an antibacterial agent, and signals the migration of germ-fighting cells to sites of infection. SAA1 also functions as an apolipoprotein of the HDL complex.
Elevated levels of SAA1 ultimately affect secondary amyloidosis, extracellular amassing of amyloid fibrils, resulting from a circulating precursor, in a variety of tissues and organs. The most widespread type of amyloidosis appears secondary to chronic inflammatory disease, mainly rheumatoid arthritis. The SAA1 cleavage product a designated amyloid protein A is deposited systemically as amyloid in vital organs such as the liver, spleen, and kidneys in chronic inflammatory diseases patients. These deposits are extremely insoluble and resistant to proteolysis; they disrupt tissue structure and compromise performance.

Major Histocompatibility Complex Class I F (HLA-F) belongs to the MHC family which takes part in the presentation of antigens to the T cell receptor. HLA-F is a member of the class I molecules which are expressed in virtually all cells. There are 2 classes of HLA antigens. Class I molecules takes an important part in the immune system by presenting peptides derived from the endoplasmic reticulum.

HLA-G (Major Histocompatibility Complex Class I G) is a member of the HLA class I heavy chain paralogues. This class I molecule is a heterodimer which comprises a heavy chain as well as a light chain, beta-2 microglobulin, while the heavy chain is fixed in the membrane. HLA-G is expressed on fetal derived placental cells. HLA-G is a non-classical class-I HLA molecule linked with immuno-modulatory & anti-inflammatory properties which interacts with inhibitory receptors such as, ILT2/ILT4/KIR2DL4, that are present on different immune cells. HLA-G inhibits the proliferation of T cells, B cells & natural killer cells, moreover it also induces regulatory T cells.

BMP2 belongs to the transforming growth factor-beta (TGFB) superfamily. Bone morphogenic protein induces bone formation. BMP2 is a candidate gene for the autosomal dominant disease of fibrodysplasia (myositis) ossificans progressiva.

Proprotein Convertase Subtilisin/Kexin Type 1 Inhibitor (PCSK1N) takes part in the control of the neuroendocrine secretory pathway. PCSK1N inhibits prohormone convertase 1, which regulates the proteolytic cleavage of neuroendocrine peptide precursors. PCSK1Nslows down convertase-mediated processing of proopiomelanocortin and proenkephalin and also monitors the intracellular timing of PCSK1.

Vascular endothelial growth factor is an important signaling protein involved in both vasculogenesis and angiogenesis. As its name implies, VEGF activity has been mostly studied on cells of the vascular endothelium, although it does have effects on a number of other cell types (e.g. stimulation monocyte/ macrophagemigration, neurons, cancer cells, kidney epithelial cells ).VEGF mediates increased vascular permeability, induces angiogenesis, vasculogenesis and endothelial cell growth, promotes cell migration, and inhibits apoptosis. In vitro, VEGF has been shown to stimulate endothelial cell mitogenesisand cell migration. VEGF is also a vasodilator and increases microvascular permeability and was originally referred to as vascular permeability factor.Elevated levels of this protein are linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in this gene have been associated with proliferative and nonproliferative diabetic retinopathy.

HB-EGF is an EGF related growth factor which signals via the EGF receptor, and stimulates the proliferation of SMC (smooth muscle cells), fibroblasts, epithelial cells and keratinocytes. HB-EGF is expressed in various cell types and tissues, including vascular endothelial cells and SMC, macrophages, skeletal muscle, keratinocytes and particular tumor cells. HB-EGF’s ability to explicitly bind HPR sulfate proteoglycans is dissimilar from other EGF-like molecules, and might be related to the enhanced mitogenic activity, relative to EGF, that HB-EGF exerts on smooth muscle cells.

Leptin takes an important part in the regulation of energy balance and body weight control.After entering the circulation, Leptin binds LEPRwhich results in the activation of several major signalling pathways. In the hypothalamus Leptin acts as an appetite-regulating factor that induces a decrease in food intake and an increase in energy consumption and also regulates bone mass and secretion of hypothalamo-pituitary-adrenal hormones. In the periphery, increases basal metabolism, regulates pancreatic beta-cell function and insulin secretion and affects innate and adaptive immunity.

Tissue plasminogen activator (abbreviated PLAT or tPA) is a secreted serine proteasewhich converts the proenzymeplasminogento plasmin, a fibrinolyticenzyme. Plasminogen is synthesized as a single chain which is cleaved by PLAT into the two chain disulfide linked plasmin.
This enzyme plays a role in cell migrationand tissue remodeling. Increased enzymatic activity causes hyperfibrinolysis, which manifests as excessive bleeding; decreased activity leads to hypofibrinolysiswhich can result in thrombosisor embolism.

PSMB10 is a member of the proteasome B-type family (T1B family) which is a 20S core beta subunit. The proteasome is a multicatalytic proteinase complex with an extremely ordered ring-shaped 20S core structure. This core structure is comprised of four rings of 28 non-identical subunits; two rings are composed of seven alpha subunits and two rings are composed of seven beta subunits. Proteasomes are circulated in eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. A crucial function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides. PSMB10 gene expression is induced by INFg, and it replaces catalytic subunit 2 (proteasome beta 7 subunit) in the immunoproteasome.

The type II transmembrane protein FASLG is a member of the tumor necrosis factor (TNF) superfamily. A fas ligand/receptor interaction has a significant part in the regulation of the immune system and the advancement of cancer. FASLG is expressed on the activated T cell surface as a nondisulfidelinked homotrimer. FASLG binding to Fas/CD95/TNFRSF6 on a nearby cell prompts apoptosis in the Fas expressing cell. FASLG is released from the cell surface by metalloproteinases as a soluble molecule that stays trimeric and is able to bind with Fas, but its capability to activate apoptosis is radically reduced. In addition, FASLG binds to DcR3 - a soluble trap receptor with no signal transduction capabilities. Flawed Fas-mediated apoptosis causes oncogenesis in addition to drug resistance in existing tumors. Constitutive expression of FASLG in a variety of tumors enables their immune evasion. Both mouse and human FASLG are active on mouse and human cells.

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.

The Regulatory (R) subunit of Protein Kinase A (PKA) inhibits its kinase activity by shielding the Catalytic (C) subunit from physiological substrates. This inhibition is reversed in response to extra-cellular signals that increase cAMP levels in the cytoplasm. Upon cAMP binding to R, C is allosterically released from R, activating a spectrum of downstream signaling cascades. Crystallographic data indicated that a series of distinct conformational changes within CBD-A must occur to relay the cAMP signal from the cAMP binding site to the R:C interaction interface. One critical cAMP relay site within the CBD-A of R has been identified as Asp170 because the D170A mutation selectively reduces the negative cooperativity between the cAMP- and C-recognition sites (i.e. the KD for the R:C complex in the presence of cAMP is reduced by more than 12-fold), without significantly compromising the high affinity of R for both binding partners.

Histamine N-Methyltransferase or HNMT, is located in the cell cytosol. Sadenosyl-L-methionine acts as a methyl donor for HNMT which inactivates histamine. By inactivation of histamine, it affects the immune system’s response. HNMT acts on histamine in body tissues such as kidney, central nervous system and bronchus. The protein has a crucial part in the airway response to histamine & histamine degradation process and regulation.

CCNH is part of the cyclin family that is known for its protein abundance through the cell cycle. Cyclins act as regulators of CDK kinases. CCNH forms a complex with CDK7 kinase and ring finger protein MAT1. The kinase complex is able to phosphorylate CDK2 and CDC2 kinases, therefore it functions as a CDK-activating kinase (CAK). CCNH and its kinase collaborator are components of TFIIH, as well as RNA polymerase II protein complexes.

Endothelial cells express three different vascular endothelial growth factor (VEGF) receptors, belonging to the family of receptor tyrosine kinases (RTKs). They are named VEGFR-1 (Flt-1), VEGFR-2 (KDR/Flk-1), VEGFR-3 (Flt-4). Their expression is almost exclusively restricted to endothelial cells, but VEGFR-1 can also be found on monocytes, dendritic cells and on trophoblast cells. The flt-1 gene was first described in 1990. The receptor contains seven immunoglobulin-like extracellular domains, a single transmembrane region and an intracellular splited tyrosine kinase domain. Compared to VEGFR-2 the Flt-1 receptor has a higher affinity for VEGF but a weaker signaling activity. VEGFR-1 thus leads not to proliferation of endothelial cells, but mediates signals for differentiation. Interestingly a naturally occuring soluble variant of VEGFR-1 (sVEGFR-1) was found in HUVE supernatants in 1996, which is generated by alternative splicing of the flt-1 mRNA. The biological functions of sVEGFR-1 still are not clear, but it seems to be an endogenous regulator of angiogenesis, binding VEGF with the same affinity as the full-length receptor.