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CD59 is a cell surface glycoprotein which regulates complement-mediated cell lysis, and it is involved in lymphocyte signal transduction. CD59 is an effective inhibitor of the complement membrane attack complex, whereby it binds complement C8 and/or C9 during the compilation of this complex, thus inhibiting the incorporation of multiple copies of C9 into the complex, which is essential for osmolytic pore formation. In addition, CD59 has a role in signal transduction pathways in the activation of T cells. CD59 gene mutations cause CD59 deficiency, a disease resulting in hemolytic anemia and thrombosis, and which causes cerebral infarction.

Glycolipid Transfer Protein Domain Containing 1 (GLTPD1) belongs to the GLTP family. GLTPD1 mediates the intracellular transfer of ceramide-1-phosphate between organelle membranes and the cell membrane. GLTPD1 is essential for normal structure of the Golgi stacks. In addition, GLTPD1 is able to bind phosphoceramides with a diversity of aliphatic chains, however GLTPD1 has a preference for lipids with saturated C16:0 or monounsaturated C18:1 aliphatic chains. Moreover, GLTPD1 is inefficient with phosphoceramides which contains lignoceryl (C24:0). GLTPD1 participates in the regulation of the cellular levels of ceramide-1-phosphate, and in that way contributes to the regulation of phospholipase PLA2G4A activity and the release of arachidonic acid.

CK-MB Type II possesses the naturally occurring carboxy-terminal amino acid lysine.
This occurs during a myocardial infarct (MI or heart attack) when CK-MB Type II is released from damaged heart muscle, and the C-terminal lysine is cleaved in the blood stream, thus creating CK-MB Type I. This difference can be exploited in diagnosis of an MI.

Chemokine (C-C motif) ligand 2 (CCL2) is a small cytokine belonging to the CC chemokine family that is also known as monocyte chemotactic protein-1 (MCP-1). It is found at the site of tooth eruption and bone degradation. In the bone, CCL2 is expressed by mature osteoclasts and osteoblasts and is under the control of nuclear factor ?B (NF?B).CCL2 recruits immune cells, such as monocytes, to sites of tissue injury and infection.This chemokine is produced as a protein precursor containing signal peptide of 23 amino acids and a mature peptide of 76 amino acids. It is a monomeric polypeptide, with a molecular weight of approximately 13kDa. As with many other CC chemokines, CCL2 is located on chromosome 17 in humans.The cell surface receptors that bind CCL2 are CCR2 and CCR5

MDS1 is a transcriptional regulator and oncoprotein which takes part in hematopoiesis, development, cell differentiation, apoptosis and proliferation. MDS1 is able to interact with CTBP1, SMAD3, CREBBP, KAT2B, MAPK8, and MAPK9. Overexpression, as a result of translocation with the AML1 gene, is known to cause leukemia. A number of transcript variants encoding several different isoforms were found.

ACAT2 enzyme participates in lipid metabolism. ACAT2 takes part in lipoprotein assembly, catalyzing cholesterol esterification in mammalian cells. ACAT2 is an integral membrane protein that localizes to the endoplasmic reticulum of human intestinal cells. ACAT2 deficiency contributes to severe mental retardation and hypotonus.

ANGPTL3 and ANGPTL4 are angiopoietin-like proteins secreted and expressed mainly by the liver, their role being the regulation of triglyceride metabolism by inhibiting the lipolysis of triglyceride-rich lipoproteins. During different nutritional states (feeding/fasting) the levels of the circulating triglycerides are regulated by Angptl3 and Angptl4 through differential inhibition of Lipoprotein lipase (LPL) as shown by the experimental data. The molecular structure of ANGPTL3 is similar to that of the angiopoietins (vascular endothelial growth factors). Deletion mutants of human Angiopoietin 5 were used in order to demonstrate that the N-terminal domain (fragment 17-207) and not the C-terminal fibrinogen-like domain (fragment 207-460) increased the plasma triglyceride levels in mice.

CBR1 is one of numerous monomeric, NADPH-dependent oxidoreductases having ubiquistly specificity for carbonyl compounds. CBR1 is broadly distributed in human tissues. CBR1 metabolizes toxic environmental quinones and pharmacological relevant substrates such as the anticancer doxorubicin. CBR1 converts prostaglandin E2 to prostaglandin F2-alpha.

Pyruvate kinase is a key enzyme in the glycolytic pathway. The M2 isoenzyme of pyruvate kinase is specifically expressed at high levels in tumor cells, and can be measured in plasma of patients with advanced breast cancer. The marker is useful for measuring disease activity, sensitivity to chemotherapy and recurrence.

CRK belongs to the signaling adapter protein family which binds to several tyrosine-phosphorylated proteins. CRK is involved in many cellular processes such as apoptosis, proliferation, and differentiation. CRK has a modular domain architecture consisting of an SH2 followed by two SH3 domains (src-homology domains). The N-terminal SH2 domain of the CRK protein functions as a positive regulator of transformation whereas the C-terminal SH3 domain functions as a negative regulator of transformation.

A natural cytotoxicity receptor (NCR) NKp46 has been shown to represent a novel NK cell-specific molecule involved in human NK cell activation. The natural cytotoxicity receptors (NCRs) are a recently characterized family of Ig-like activation receptors that appear to be major triggering receptors in tumor cell recognition. The three known NCRs include NKp46 and NKp30, which are expressed on circulating NKcells, and NKp44, which is expressed only on activating NK cells. NKp46 has been implicated in NK cell-mediated lysis of several autologous tumor cells, pathogen-infected cell lines and mononuclear phagocytes infected with an intracellular bacterium. The Lysis of tumor cells by NK-cells involves recognition by NKp46 of heparan sulfate moieties of membrane heparan sulfate proteoglycans. Furthermore, NKp46 is a surface receptor involved in NK-cell cell death by apoptosis. NKp46 has two extracellular Ig-like domains followed by a ~40 residue stalk region, a type I transmembrane domain, and a short cytoplasmic tail. The extracellular Ig-like domain of NKp46 (22-255aa) is purified by FPLC gel-filtration chromatography, after refolding of the isolated inclusion bodies in a redox buffer. In addition, engagement of the antigen with the monoclonal antibody stimulates intracellular calcium levels and the synthesis of cytokines. CD59 is an NKp46 coreceptor (by physical association) together they activate cytotoxicity of human NK-cells, their engagement results in tyrosine phosphorylation of CD3-zeta chains associated with NKp46. Reduced cell surface expression of NKp46 and other NK-cell receptors is linked to the impaired NK-cell cytolytic function in viremic HIV-1 infection.

F-ATPase delta (ATP5D) catalyzes ATP synthesis, employing an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation. ATP synthase is composed of 2 linked multi-subunit complexes: F1-the soluble catalytic core and Fo- the membrane-spanning component, which comprise the proton channel. The catalytic portion of mitochondrial ATP synthase consists of five different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alphas, 3 betas, and a single representative of the other three. The proton channel consists of three main subunits-a, b, c. ATP5D is the delta subunit of the catalytic core.

Fc Fragment Of IgG Receptor And Transporter also known as FCGRT is a transmembrane glycoprotein with structural homology to MHC class 1 proteins. FCGRT is widely expressed in endothelial and epithelial cells and takes a vital part in IgG homeostasis. Moreover, FCGRT is expressed in neutrophils in addition myeloid antigen presenting cells. FCGRT can enhance IgG-meditated phagocytosis as well as antigen presentation by heses cells, however it promotes the degradation of opsonizing IgG rather than returning it to the circulation.

Endoglin is a type I membrane glycoprotein located on cell surfaces and is part of the TGF beta receptor complex.
The protein consists of a homodimer of 180 kDA with disulfide links. It has been found on endothelial cells, activated macrophages, fibroblasts, and smooth muscle cells. Endoglin has been found to be part of the TGF-beta1 receptor complex. It thus may be involved in the binding of TGF-beta1, TGF-beta3, activin-A, BMP-2, and BMP-7. Beside TGF-beta signaling endoglin may have other functions. It has been postulated that endoglin is involved in the cytoskeletal organization affecting cell morphology and migration. Endoglin has a role in the development of the cardiovascular system and in vascular remodeling. Its expression is regulated during heart development . Experimental mice without the endoglin gene die due to cardiovascular abnormalities.

Signal-Regulatory Protein Alpha, SIRPA belongs to the signal-regulatory-protein (SIRP) family, as well as theimmunoglobulin super family. The members of the SIRP family are receptor-type transmembrane glycoproteins which areinvolved in the negative regulation of receptor tyrosine kinase-coupled signaling processes. SIRPA can bephosphorylated by tyrosine kinases. The phospho-tyrosine residues of this PTP have been shown to recruit SH2domain containing tyrosine phosphatases (PTP), and perform as substrates of PTPs. SIRPA take part insignal transduction mediated by a variety of growth factor receptors. CD47 has been shown to be a ligand for SIRPA.

Angiotensin Converting Enzyme (ACE) is a zinc metallopeptidase vital for blood pressure control and salt and water metabolism.ACE converts angiotensin I to angiotensin II by release of the terminal His-Leu which causes the vasoconstrictor activity of angiotensin to increase.ACE inactivates bradykinin, a potent vasodilator and has also a glycosidase activity which releases GPI-anchored proteins from the membrane by cleaving the mannose linkage in the GPI moiety.

CTSW protein belongs to the peptidase C1 family. CTSW is a cysteine proteinase with a detailed role in the regulation and mechanism of T-cell cytolytic activity. The encoded CTSW is linked to the membrane inside the endoplasmic reticulum of natural killer and cytotoxic T-cells. CTSW expression is up-regulated by interleukin-2.

EPCAM is a carcinoma-associated antigen and belongs to a family which includes at least 2 type I membrane proteins. The EPCAM protein has a role in embryonic stem cells proliferation and differentiation. EPCAM is used as a target for immunotherapy treatment of human carcinomas. EPCAM is expressed on most normal epithelial cells and gastrointestinal carcinomas and acts as a homotypic calcium-independent cell adhesion molecule. Epithelial cell adhesion molecules (EPCAM) can act as a physical homophilic interaction molecule between intestinal epithelial cells (IECs) and intraepithelial lymphocytes (IELs) at the mucosal epithelium for supplying immunological barrier as a first line of defense against mucosal infection. EPCAM gene mutations result in congenital tufting enteropathy.

TNFRSF13B (TACI) is a transmembrane receptor protein found predominantly on the surface of B cells (a significant part of the immune system). TACI was at first discovered owing to its ability to interact with calcium-modulator and cyclophilin ligand (CAML). Later on, it was found that TACI plays a key role in humoral immunity by interacting with two members of the TNF family. Also, TACI controls T cell-independent B cell antibody responses, isotype switching, and B cell homeostasis.

FKBP4 is part of the immunophilin protein family, which takes part in immunoregulation and necessary cellular processes concerning protein folding and trafficking. FKBP4 is a cis-trans prolyl isomerase that connects to the immunosuppressants FK506 and rapamycin. FKBP4 has high structural and functional similarity to FKBP1A, though, FKBP4 does not have immunosuppressant activity when complexed with FK506. FKBP4 is known to connect with phytanoyl-CoA alpha-hydroxylase. FKBP4 associates with HSP90 & HSP70 thus takes part in the intracellular trafficking of hetero-oligomeric forms of the steroid hormone receptors. FKBP4 highly associates with adeno-associated virus type 2 vectors (AAV) resulting in a considerable increase in AAV-mediated transgene expression in human cell lines. FKBP4 is involved in the optimal use of AAV vectors in human gene therapy.

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.

CD30 Ligand (TNFSF8) is a cytokine which is a member of the tumor necrosis factor (TNF) ligand family. The TNFSF8 cytokine is a ligand for TNFRSF8/CD30, which is a cell surface antigen and a marker for Hodgkin lymphoma and related hematologic malignancies. The employment of the TNFSF8 cytokine expressed on B cell surface has an inhibitory role in modulating Ig class switch. TNFSF8 enhances cell proliferation of some lymphoma cell lines, while inducing cell death and reducing cell proliferation of other lymphoma cell lines. The pleiotropic biological activities of the TNFSF8 cytokine on different CD30+ lymphoma cell lines has a pathophysiologic role in Hodgkin's and some non-Hodgkin's lymphomas.

Antioxidant enzyme Glutathione S- Transferase (GST) is thought to do the primary cellular defense mechanism against reactive oxygen species. GST reduces lipid hydroperoxides through its Se-independent glutathione peroxidase activity. The enzyme also detoxifies lipid peroxidation end products such as 4-hydroxynonenal (4-HNE).
The soluble GST is a 26 kDa protein which occurs as a dimer in all aerobic organisms. Each monomer has two domains, one that binds GSH and is an /-structure similar to thioredoxin and the other, all helical, that binds the hydrophobic substrate. The GST -fusion protein expression system is a widely used recombinant protein expression system that allows a peptide or a regulatory protein domain to be expressed as a fusion to the C-terminus of Schistosoma japonicum GST. Fusion proteins also possess GST -enzymatic activity and can undergo dimerization similar to in vivo. The fusion protein can be purified via GST -affinity column chromatography. In most cases, the desired peptides or domains are removed from GST by applying a specific protease that recognizes and cleaves the linker between the protein domain and GST. The technique has been widely used to generate different kinds of proteins for crystallization, molecular immunology studies, the production of vaccines and studies involving protein-protein and protein-DNA interactions.