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Leukemia Inhibitory Factor also called LIF is a lymphoid factor that promotes long-term maintenance of embryonic stem cells by suppressing spontaneous differentiation. Leukemia Inhibitory Factor has several functions such as cholinergic neuron differentiation, control of stem cell pluripotency, bone & fat metabolism, mitogenesis of factor dependent cell lines & promotion of megakaryocyte production in vivo. Human and mouse LIF exhibit a 78% identity in its amino acid sequence.

Haloacid dehalogenase-like hydrolase domain-containing protein 1A (HDHD1A) is a member of the adiponutrin family. HDHD1A is interesting because it is an X-linked gene that escapes X-inactivation. HDHD1A is particularly important in the perception of human X chromosome structural organization as well as the mechanism of X-inactivation.

Plasminogen activator inhibitor-1 is the principal inhibitor of tissue plasminogen activator(tPA) and uPA, the activators of plasminogenand hence fibrinolysis(the physiological breakdown of blood clots). It is a serine protease inhibitor(serpin) protein (SERPINE1). The other PAI, plasminogen activator inhibitor-2(PAI-2) is secreted by the placentaand only present in significant amounts during pregnancy. In addition, protease nexinacts as an inhibitor of tPA. SERPINE1, however, is the main inhibitor of the plasminogen activators.

Heparanase is an endo-β-D-glucuronidase, which degrades heparan sulfate side chains of heparan sulfate proteoglycans (HSPGs) in the extracellular matrix. Heparanase plays an important role in ECM degradation, facilitating the migration and extravasation of tumor cells and inflammatory leukocytes (1,2,3). Upon degradation, heparanase releases growth factors and cytokines that stimulate cell proliferation and chemotaxis (4,5). Heparanase is a heterodimer comprised of a 50 kDa subunit harboring the active site and a 8 kDa subunit. It is produced as a latent 65 kDa precursor and proteolytically processed to its active form (1,6). Heparanase is highly expressed in myeloid leukocytes (i.e. neutrophils) in platelets and in human placenta. Human heparanase was found to be upregulated in various types of primary tumors, correlating in some cases with increased tumor invasiveness and vascularity and with poor prospective survival (7,8).

Human interleukin family 1, member 7 (IL1F7) belongs to the interleukin 1 cytokine family. There are 5 alternatively spliced transcript variants encoding distinct isoforms with distinct expression profiles. The longest IL-1F7 transcript, named IL1F7b or IL1F7 isoform 1, encodes a 218 aa residues proprotein and containing a 45 aa propeptide which is cleaved to produce a mature protein. IL1F7b binds to IL18 Rb with low affinity however it doesn’t exert any IL18 agonistic or antagonistic effects. IL1F7b also binds IL18BP (interleukin 18 binding protein), which is an inhibitory binding protein of interleukin 18 (IL18), and afterward forms a complex with IL18 receptor beta subunit, and through which it inhibits the activity of IL18.

Fibroblast Growth Factor 17 (FGF17) belongs to the fibroblast growth factor (FGF) family. FGF family members have broad mitogenic and cell survival activities, and are involved in various biological processes including embryonic development cell growth, morphogenesis, tissue repair, tumor growth and invasion. The FGF17 gene is highly expressed in the cerebellum and cortex. The mouse homolog of the FGF17 gene is localized to specific sites in the midline structures of the forebrain, the midbrain-hindbrain junction, developing skeleton and developing arteries, suggesting a role in central nervous system, bone and vascular development.

Ara h 2 comprises of 2 isoforms: Ara h 2.0101 and Ara h 2.0201. Ara h 2.0201 is the most important peanut allergen which binds IgE. Ara h 2.0201 is a Weak inhibitor of trypsin and is a conglutin storage protein which accounts together with Ara h 6.0101 for the majority of the IgE immune response.

Transforming Growth Factor Beta Induced protein also known as TGFBI is an extracellular matrix protein induced by transforming growth factor (TGF)-beta 1. TGFBI protein is involved in cell growth, cell differentiation, wound healing and cell adhesion. In addition, some missense mutations of TGFBI were identified in families affected with human autosomal dominant corneal dystrophies. TGFBI gene encodes for a 683 amino-acid protein containing an RGD motif and four internal repeated domains which have highly conserved sequences founded in several species (Fasciclin domain).

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.

LIM domain only 1 (LMO1) is a protein-coding gene. LMO1 encodes a transcriptional regulator which contains two cysteine-rich LIM domains but lacks a DNA-binding domain. LIM domains might play a part in protein interactions; hence the protein may regulate transcription by competitively binding to specific DNA-binding transcription factors.

CD166 antigen isoform 2 (ALCAM) is a type 1 membrane glycoprotein and belongs to the immunoglobulin superfamily. ALCAM is expressed on thymic epithelium, microvascular endothelium, activated lymphocytes and monocytes, and monocyte-derived dendritic cells. CD166 and CD6 interaction plays a role in T cell development and T cell regulation, as well as in the binding of T cells and B cells to activated leukocytes.

Osteoprotegerin acts as decoy receptor for rankl and thereby neutralizes its function in osteoclastogenesis. OPG inhibits the activation of osteoclasts and promotes osteoclast apoptosis in vitro. Bone homeostasis seems to depend on the local rankl/opg ratio. Osteoprotegerin may also play a role in preventing arterial calcification. May act as decoy receptor for trail and protect against apoptosis. Trail binding blocks the inhibition of osteoclastogenesis.

ESM1, also knows as, Endothelial cell-specific molecule 1 is a protein encoded by a gene called ESM1 in humans. ESM1 is a secreted protein that is highly expressed in human kidney and lung tissues (in the endothelial cells). There are suggestions regarding the protein’s involvement in endothelium-dependent pathological diseases, due to his regulation that is performed by cytokines.

CFLAR contains two death effector domains (DEDs) and a caspase-like domain. CFLAR may play a critical role between cell survival and cell death pathway in mammalian cells. CFLAR also interacts with adapter protein FADD and caspase-8 and -10, and potently inhibits apoptosis induced by all known death receptors DR3 (death receptor 3), TRAIL-R (TNF-related apoptosis-inducing ligand receptor) and TNFR1 (tumor necrosis factor receptor 1).

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.

Homeodomain-only protein (HOPX) functions via its interaction with SRF, thus modulating the expression of SRF-dependent cardiac-specific genes and cardiac development. HOPX inhibits SRF-dependent transcription either by hindering SRF binding to DNA or by engaging histone deacetylase (HDAC) proteins which prevent transcription by SRF. HOPX is a homeodomain protein which lacks certain conserved residues required for DNA binding. HOPX overexpression causes cardiac hypertrophy.

Caspase Recruitment Domain Family, Member 17 (CARD17) is a regulator of procaspase-1/CASP1 activation involved in the regulation of the proteolytic maturation of pro-IL-1beta/IL1B and its release throughout inflammation. CARD17 inhibits the release of IL1B in reaction to LPS in monocytes. Though, unlike CASP1, CARD17 do not induce NF-kappa-B activation.

PFKM is a regulatory glycolytic enzyme that converts fructose 6-phosphate and ATP into fructose 1,6-bisphosphate (through PFK-1), fructose 2,6-bisphosphate (through PFK-2) and ADP. Three phosphofructokinase isozymes exist in humans: muscle, liver and platelet. Mutations in PFKM gene have been related with glycogen storage disease type VII, also identified as Tarui disease.

p59-Fyn is a member of the protein-tyrosine kinase oncogene family. p59fyn is a membrane-associated non-receptor protein tyrosine kinase that belongs to the Src-family of kinases. p59-Fyn encodes a membrane-associated tyrosine kinase which is implicated in the control of cell growth. p59-Fyn associates with the p85 subunit of phosphatidylinositol 3-kinase and interacts with the fyn-binding protein. The unique N-terminal domain of p59fyn interacts with the CD3 and eta chains of the TcR. p59fyn can bind other proteins (p82 and p116) through its SH2 and SH3 domains, which may act as substrates or regulators of fyn activity. p59fyn is highly expressed in brain suggesting that it may have a role in the sensory nervous network and in myelination at early stages of CNS formation. Distinct isoforms exist due to alternative splicing.

Simian immunodeficiency virus, SIV, is a retrovirusthat is found in strains, having the HIV-1and HIV-2specific strains that infect humans. SIV strains may cause an AIDS-like immune deficiency known as SAIDS (simian acquired immunodeficiency syndrome) if they cross species boundaries. HIV-2 is more similar to SIV strains than to HIV-1, suggesting for the first time the simian origin of HIV. HIV-2 is derived from the SIV strain found in sooty mangabeys whereas HIV-1, the predominant virus found in humans, is derived from SIV strains infecting chimpanzees.

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.

The precise role of CFLAR is not yet revealed but it seems it is vital in apoptosis regulation downstream of all identified death receptors.