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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.

RNA 3'-Terminal Phosphate Cyclase (RTCA) encodes a part of the RNA 3'-phosphate cyclase family. RTCA takes part in RNA metabolism by catalyzing the ATP-dependent conversion of the 3'-phosphate of RNA substrates to a 2',3'-cyclic phosphodiester. RTCA is involved in some phases of cellular RNA processing.

Discoidin Domain Receptor Tyrosine Kinase 1 (DDR1) is a transmembrane glycoprotein which is a part of the discoidin-like domain containing subfamily of receptor tyrosine kinases. DDR1 functions as cell surface receptor for fibrillar collagen and regulates cell attachment to the extracellular matrix, remodeling of the extracellular matrix, cell migration, differentiation, survival and cell proliferation. DDR1 is expressed in epithelial cells, mainly in the kidney, lung, gastrointestinal tract, and brain and is significantly overexpressed in several human tumors.

The Sec61 complex is the key component of the protein translocation apparatus of the ER (endoplasmic reticulum) membrane. Oligomers of the Sec61 complex construct a transmembrane channel where proteins are translocated across and incorporated into the ER membrane. This complex consists of 3 membrane proteins- alpha, beta, and gamma. The SEC61B gene encodes the beta-subunit protein. The Sec61 subunits are also detected in the post-ER compartment, suggesting that these proteins can get out of the ER and recycle back.

Endoglin is a type I membrane glycoprotein located on cell surfaces and is part of the TGF beta receptor complex.The Endoglin protein consists of a homodimer of 180 kDA with disulfide links. Endoglin has been found on endothelial cells, activated macrophages, fibroblasts, and smooth muscle cells. Furthermore, Endoglin has been found to be part of the TGF-beta1 receptor complex. Endoglin 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. Endoglin expression is regulated during heart development . Experimental mice without the endoglin gene die due to cardiovascular abnormalities.

Progastricsin-C (PGC) is an aspartic proteinase which is synthesized in the gastric mucosa as inactive precursors. PGC is a part of the peptidase family A1 and contains a prosegment which is responsible for stabilizing the inactive form and preventing the entrance of the substrate to the active site. PGC is used as a biomarker for various gastric diseases including Helicobacter pylori related gastritis. PGC is also hydrolyzes various proteins.

Fibrinogen gamma chain isoform gamma-A (FGG) is the gamma component of fibrinogen, which is a blood-borne glycoprotein, comprised of 3 pairs of nonidentical polypeptide chains. FGG along with fibrinogen alpha (FGA) and fibrinogen beta (FGB) polymerizes to form an insoluble fibrin matrix. Following vascular injury, FGG is cleaved by thrombin to create fibrin, which is the most abundant component of blood clots. FGG functions during the early stages of wound repair to stabilize the lesion and guide cell migration during re-epithelialization. Moreover, different cleavage products of fibrinogen and fibrin regulate cell adhesion and spreading, exhibit vasoconstrictor and chemotactic activities, and are mitogens for a number of cell types. Maternal fibrinogen is vital for successful pregnancy. FGG gene mutations lead to some disorders, including dysfibrinogenemia, hypofibrinogenemia and thrombophilia. Fibrin accumulation is also linked with infection, where it protects against IFNG-mediated hemorrhage.

Kallikreins are a subgroup of serine proteases having various physiological functions. Many kallikreins are implicated in carcinogenesis and some have potential of becoming novel cancer and other disease biomarkers. Kallikrein-13 (KLK13) is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. KLK13 gene expression is regulated by steroid hormones and may be useful as a marker for breast cancer.

Podocalyxin (PODXL) is a greatly glycosylated transmembrane sialoprotein in the CD34 and endoglycan family. The PODXL protein is involved in the regulation of both adhesion and cell morphology and cancer progression. PODXL functions as an anti-adhesive molecule, which retains an open filtration pathway between neighboring foot processes in the podocyte by charge repulsion. Moreover, PODXL serves as a pro-adhesive molecule, enhancing the adherence of cells to immobilized ligands, increasing the rate of migration and cell-cell contacts in an integrin-dependent manner.

Kallikrein-5 (KLK5) is a member of the serine protease family of proteolytic enzymes. KLK5 is expressed in various tissues including the salivary gland, stomach, uterus, lung, thymus, prostate, colon, brain, thyroid, and trachea. KLK5 expression is up-regulated by estrogens and progestins. KLK5 is secreted and may be involved in desquamation in the epidermis. Kallikreins which are a subgroup of serine proteases, have distinct physiological functions. Many kallikreins are associated with carcinogenesis and some have potential as novel cancer and other disease biomarkers. The KLK5 gene is one of the 15 kallikrein subfamily members located in a cluster on chromosome 19.

Tyrosylprotein Sulfotransferase 1, also known as TPST1 is the enzyme which catalyzes the sulfation reaction of protein tyrosines, a post-translational modification of proteins. TPST1 belongs to the protein sulfotransferase family. In addition, TPST1 utilizes 3'-Phosphoadenosine-5'-phosphosulfate (PAPS) as the sulfonate donor and also binds proteins with target tyrosine residues to eventually form the tyrosine O-sulfate ester group in addition to the desulfonated 3’-phosphoadenosine-5’-phosphate.

Thioredoxin Reductase 3 Neighbor, also known as TXNRD3NB is expressed in pancreas, esophagus, bone marrow and keratinocytes. TXNRD3NB shares overlapping exons with TXNRD3. In addition the initiation codon is found in exon 3 of the TXNRD3IT1 gene.

The 14-3-3 family of proteins plays a key regulatory role in signal transduction, checkpoint control, apoptotic and nutrient-sensing pathways. 14-3-3 proteins are highly conserved and ubiquitously expressed. There are at least seven isoforms, β, γ, ε, σ, ζ, τ and η that have been identified in mammals. The 14-3-3 epsilon, a subtype of the 14-3-3 family of proteins, was thought to be brain and neuron-specific. It has been shown to interact with CDC25 phosphatases, RAF1 and IRS1 proteins, suggesting its role in diverse biochemical activities related to signal transduction, such as cell division and regulation of insulin sensitivity. It has also been implicated in the pathogenesis of small cell lung cancer.

Pollen allergen Car b 1 isoform (Car b 1.0109) causes an allergic reaction in humans.

Stress-Induced Protein SAM22 (Gly m 4.0101) causes an allergic reaction in humans. Gly m 4 is the main soy allergen for patients allergic to birch pollen with soy allergy.

Major pollen allergen Cor a 1 (Cor a 1.0103) causes an allergic reaction in human. The Cor a 1 isoforms exhibit different antigenic and allergenic properties.

Beta-crystallin A4 (CRYBA4) is a member of the beta/gamma-crystallin family which are the dominant structural components of the vertebrate eye lens. Beta-crystallins construct aggregates of various sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. The CRYBA4 gene being a beta acidic group member is part of a gene cluster with beta-B1, beta-B2, and beta-B3.

The Melanoma Inhibitory protein (MIA) was identified as an inhibitor of in vitro growth of malignant melanoma cells. The protein contains a SH3 domain.
MIA acts as a potent tumor cell growth inhibitor for malignant melanoma cells and some other neuroectodermal tumors, including gliomas, in an autocrine fashion. In a study of human melanoma cell lines with different metastatic capacity MIA mRNA expression appeared to be inversely correlated with pigmentation. MIA has been shown to represent a very sensitive and specific serum marker for systemic malignant melanoma that might be useful for staging of primary melanomas, detection of progression from localized to metastatic disease during follow-up, and monitoring therapy of advanced melanomas.

Hemochromatosis (HFE) is a member of the MHC class I family. The Hemochromatosis protein contains 1 Ig-like C1-type (immunoglobulin-like) domain. HFE is a membrane protein, which is similar to MHC class I-type proteins and associates with beta-2 microglobulin (beta2M). It is assumed that the HFE protein acts to regulate iron absorption by regulating the interaction of the transferrin receptor (TFR) with transferrin. HFE binds to transferrin receptor (TFR) and reduces its affinity for iron-loaded transferrin.

DBI, also known as Acyl-CoA-binding protein isoform 2, is a diazepam binding inhibitor, which is regulated by hormones. DBI participates in lipid metabolism and in the displacement of beta-carbolines & benzodiazepines, which modulate signal transduction at type A gamma-aminobutyric acid receptors located in brain synapses. Moreover, during adipocyte differentiation the expression of DBI is significantly induced. DBI preforms as an acyl-CoA pool former and regulates LCFA (long-chain fatty acids) metabolism in peripheral tissues.

Platelet-activating factor acetylhydrolase 2 cytoplasmic (PAFAH2) has a marked selectivity for phospholipids with short acyl chains at the sn-2 position. PAFAH2 may share a mutual physiologic function with the plasma-type enzyme.

PDGF-AA, PDGF-BB and PDGF-AB, are potent mitogens for a variety of cell types including smooth muscle cells, connective tissue cells, bone and cartilage cells, and some blood cells. The PDGF is stored in platelet alpha-granules and released upon platelet activation. The PDGF is involved in a number of biological processes, including hyperplasia, chemotaxis, embryonic neuron development, and respiratory tubule epithelial cell development. Two distinct signaling receptors used by PDGF
have been identified and named PDGFR-alpha and PDGFR-beta. PDGFR-alpha is high-affinity receptor for each of the three PDGF forms. On the other hand, PDGFR-beta interacts with only PDGF-BB and PDGF-AB.

PDGF-BB is a member of the platelet-derived growth factor family. The four members of this family are mitogenic factors for cells of mesenchymal origin and are characterized by a motif of eight cysteines. This gene product can exist either as a homodimer (PDGF-BB) or as a heterodimer with the platelet-derived growth factor alpha polypeptide (PDGF-AB), where the dimers are connected by disulfide bonds. Mutations in this gene are associated with meningioma. Reciprocal translocations between chromosomes 22 and 7, at sites where this gene and that for COL1A1 are located, are associated with a particular type of skin tumor called dermatofibrosarcoma protuberans resulting from unregulated expression of growth factor. Two splice variants have been identified for this gene.