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Erythropoietin receptor, also known as EPOR arbitrates erythropoietin-induced erythroblast proliferation as well as differentiation. During EPO binding, EPOR activates Jak2 tyrosine kinase which activates various intracellular pathways including: Ras/MAP kinase, phosphatidylinositol 3-kinase and STAT transcription factors. Furthermore, stimulated EPOR has a function in erythroid cell survival. Mutations in EPOR may possibly produce erythroleukemia and familial erythrocytosis. In addition, dysregulation of EPOR can affect on the growth of selected tumors.

Fibroblast Growth Factors (FGFs) comprise a family of at least 18 structurally related proteins that are involved in a multitude of physiological and pathological cellular processes, including cell growth, differentiation, angiogenesis, wound healing and tumorigenesis. The biological activities of the FGFs are mediated by a family of type I transmembrane tyrosine kinases which undergo dimerization and autophosphorylation after ligand binding. Multiple forms of FGFR-1 to -3 are generated by alternative splicing of the mRNAs. A frequent splicing event involving FGFR-1 and -2 results in receptors containing all three Ig domains, referred to as the alpha isoform, or only IgII and IgIII, referred to as the ? isoform. Only the alpha isoform has been identified for FGFR-3 and FGFR-4. Additional splicing events for FGFR-1 to -3, involving the C-terminal half of the IgIII domain encoded by two mutually exclusive alternative exons, generate FGF receptors with alternative IgIII domains (IIIb and IIIc). An IIIa isoform which is a secreted FGF binding protein containing only the N-terminal half of the IgIII domain plus some intron sequences has also been reported for FGFR-1. Mutations in FGFR-1 to -3 have been found in patients with birth defects involving craniosynostosis.

EFNA3 belongs to the ephrin (EPH) family. The ephrins and EPH-related receptors include thelargest subfamily of receptor protein-tyrosine kinases which have been implicated in mediating developmental events, especially in the nervous system and in erythropoiesis. Ephrins are divided into the ephrin-A (EFNA) class and the ephrin-B (EFNB) class, based on their structures and sequence relationships. The Ephrins from the EFNA class are anchored to the membrane by aglycosylphosphatidylinositol linkage, while the others from the EFNB class are transmembrane proteins.

Glycerol-3-phosphate dehydrogenase 1-like protein (GPD1L) converts sn-glycerol 3-phosphate to glycerone phosphate. GPD1L is found in the cytoplasm, associated with the plasma membrane, where it binds the sodium channel, voltage-gated, type V, alpha subunit (SCN5A). Mutations in the GPD1L gene are the cause of SIDS (sudden infant death syndrome) and Brugada syndrome type 2 (an autosomal dominant tachyarrhythmia).

DiGeorge syndrome critical region 6-like protein (DGCR6L) shares homology with the Drosophila gonadal protein, it is expressed in gonadal tissues and germ cells, and with the human laminin gamma-1 chain which functions in cell attachment and migration. DGCR6L is located in a region of chromosome 22 involved in the DiGeorge syndrome, one aspect of a wider collection of anomalies referred to as the CATCH 22 syndrome. Moreover, it is one of two functional genes encoding nearly identical proteins which have analogous expression patterns.

Neuronal Regeneration Related Protein (NREP) has roles in neural function. NREP promotes axonal regeneration. In addition, NREP has functions in cellular differentiation. NREP protein induces differentiation of fibroblast into myofibroblast and increases retinoic-acid regulation of lipid-droplet biogenesis. NREP down-regulates the expression of TGFB1 and TGFB2 but not of TGFB3. NREP has a role in the regulation of alveolar generation.

Maltose Binding Protein is a member of the maltose/maltodextrin system of E.Coli, which is accountable for the uptake and efficient catabolism of maltodextrins. The maltose/maltodextrin is a complex regulatory and transport system involving many proteins and protein complexes.
MBP elevates the yield of its fusion partner in many cases and is often able to promote the solubility of polypeptides to which it is fused.

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).

Hairy and enhancer of split 2 (HES2) belongs to the HES family and comprised of one basic helix-loop-helix (bHLH) domain and one orange domain. The HES family members form a complex with TLE, the mammalian homologue of Groucho, and this interaction is mediated by the carboxy terminal WRPW motif of the HES proteins. Activation of Notch signaling pathway initiates activation of HES family genes throughout the interaction between Notch intracellular domain and RBPSUH (CSL). HES2 is expressed in placenta, pancreatic cancer, colon cancer with RER, cervical cancer, and in head and neck tumors.

OLR1 is a type II membrane protein which belongs to the C-type lectin family and performs as a cell-surface receptor for Ox-LDL. Ox-LDL has a part in early ather-osclerosis, which includes the transformation of monocyte-derived macro-phages to foam cells in atherosclerotic lesions. In addition, OLR1 protein triggers the activation of the NF?B signal transduction pathway.

Polymeric immunoglobulin receptor (PIGR) is responsible for transcytosis of soluble dimeric IgAs and immune. PIGR binds polymeric IgA and IgM at the basolateral surface of epithelial cells, then the complex is transported across the cell to be secreted at the apical surface.cytokines, hormones, and pathogenic stimuliregulate PIGR expression. The expression of PIGR is critically regulated by the pro-inflammatory cytokines, such as IL-1, IL-4, TNF-α, and IFN-γ.

Grancalcin is calcium-binding protein which is particularly abundant in human neutrophils. GCA is a member of the penta EF-hand (PEF) subfamily of EF-hand proteins, who also comprises calpain, sorcin, peflin, and ALG-2. GCA undergoes essential conformational changes upon binding of calcium, which subsequently exposes hydrophobic amino acid residues, that direct the protein to hydrophobic surfaces. GCA cooperates with L-plastin, a protein known to have actin bundling activity, which suggests that GCA has a part in the regulation of neutrophils adhesion.

Pro-opiomelanocortin preproprotein (POMC) is a polypeptide hormone precursor which experiences extensive, tissue-specific, post-translational processing via cleavage by subtilisin-like enzymes known as prohormone convertases. POMC regulates the corticosteroid production in the adrenal cortex. Furthermore, POMC is cleaved into ten hormone chains named NPP, g-MSH, ACTH, a-MSH, CLIP, Lipotropin b, Lipotropin g, b-MSH,b endorphin and Met-enkephalin. POMC gene defects are the cause of POMC deficiency, which is characterized by red hair and adrenal insufficiency.

Gastrokine-2 (GKN2) is expressed in the gastric mucosa. GKN2 forms a heterodimer with TFF1- disulfide linked. GKN2 interacts with TFF2.

Guanine nucleotide binding proteins are heterotrimeric signal-transducing molecules comprising alpha, beta, and gamma subunits. GNAI1 represents the alpha subunit of an inhibitory complex. Guanine nucleotide-binding protein G(i) subunit alpha (GNAI1) functions to transmit information from cell surface receptors to intracellular effectors. GNAI1 binds guanine nucleotide, can hydrolyze GTP, and can interact with other proteins. GNAI1 is part of a complex that responds to beta-adrenergic signals by inhibiting adenylate cyclase. In addition, GNAI1 functions to open atrial potassium channels.

Crystallin, Mu (CRYM) is a taxon-specific crystallin protein which binds NADPH and has sequence similarity to bacterial ornithine cyclodeaminases. CRYM doesn’t perform a structural role in lens tissue; instead CRYM binds thyroid hormone for possible regulatory or developmental roles. CRYM gene mutations are linked with autosomal dominant non-syndromic deafness. CRYM specifically catalyzes the reduction of imine bonds in brain substrates which may include cystathionine ketamine and lanthionine ketamine.

Alpha-hemoglobin stabilizing protein (AHSP) is an erythroid-specific protein that acts as a chaperone to prevent the aggregation of A-hemoglobin during normal erythroid cell development. AHSP specifically protects free A-hemoglobin from precipitation in live cells and in solution. AHSP is expected to modulate pathological states of alpha-hemoglobin excess such as beta-thalassemia. Furthermore, AHSP promotes alpha globin chain stability in human erythropoiesis. In addition, the AHSP stabilizes the alpha-Hb chain, thus avoiding its precipitation and its ability to generate ROS, which is implicated in cell death. AHSP is expressed in blood and bone marrow. AHSP subunit is a monomer, it forms a heterodimer with free alpha-hemoglobin. On the other hand, AHSP does not bind beta-hemoglobin nor alpha2beta2 hemoglobin A. AHSP is downregulated in TSEs (transmissible spongiform encephalopathies).

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.

SERPINH1 is part of the serpin superfamily of serine proteinase inhibitors. SEPINH1 expression is induced by heat shock. HSP47 localizes to the endoplasmic reticulum lumen and binds collagen therefore it is a molecular chaperone which takes part in the maturation of collagen molecules, facilitating the folding and assembly of procollagen molecules, retaining unfolded molecules within the ER, and assisting the transport of correctly folded-molecules from the ER to Golgi apparatus. Autoantibodies to HSP47 protein have been found in rheumatoid arthritis. SERPINH1 binds specifically to collagen and acts as a chaperone in the biosynthetic pathway of collagen.

cAMP-regulated phosphoprotein 19 (ARPP19) is protein phosphatase inhibitor which specifically inhibits protein phosphatase 2A (PP2A) during mitosis. When phosphorylated at Ser-62 during mitosis, ARPP19 specifically interacts with PPP2R2D (PR55-delta) and inhibits its activity, leading to inactivation of PP2A, a vital condition to maintain cyclin-B1-CDK1 activity high during M phase. ARPP19 protein may indirectly boost GAP-43 expression. The 19 kDa cAMP-regulated phosphoprotein has a role in regulating mitosis by obstructing protein phosphatase-2A.

SSR4 is a member of the TRAP-delta family. SSR4 is the delta subunit of the translocon-associated protein complex that participates in translocating proteins through the endoplasmic reticulum membrane. SSR4 positioned in the Xq28 region and organized in a compact head-to-head manner with the isocitrate dehydrogenase 3 (NAD+) gamma gene. Both genes are motivated by a CpG-embedded bidirectional promoter.

EPHB4 or Ephrin type-B receptor 4 is encoded by the EPHB4 gene in humans. The receptor and its ligands (the ephrins) take part in different developmental stages, mainly in the nervous system. EPHB4 and other Ephrin receptors are the biggest subgroup of the RTK receptors. EPHB4 binds to ephrin B2 and has a crucial part in the development of the vascular system.

PMF1-BGLAP is a locus which represents naturally occurring read-through transcription between the neighboring polyamine-modulated factor 1 (PMF1) and bone gamma-carboxyglutamate Gla protein (BGLAP) genes on chromosome 1. There are multiple transcript variants encoding isoforms as a results of alternative splicing which share sequence identity with the upstream gene product, but they have a different C-termini because of frameshifts as opposed to the downstream gene coding sequence.