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MCSFR which is also familiar as CSF1R, is part of the type3 subfamily of receptor tyrosine kinases. MCSFR is expressed mainly on cells of the monocyte and macrophage lineage, stem cells, and in the growing placenta. Most of the biological effects of this cytokine are mediated by MCSFR. MCSFR contains an extracellular ligand-binding domain, a single membrane-spanning segment, and an intracellular tyrosine kinase domain. Originally CSF1 and this receptor were implicated as vital for normal trophoblastic implantation as well as monocyte development. The role of CSF1/CSF1R in normal mammary gland development is actually very interesting since this connection has also been discovered in the biology of breast cancer with the results of abnormal expression of CSF1 and its receptor. Likewise, in Alzheimer's disease and after brain injuries an increased level of CSF1R was found in the microglia, which causes the microglia to become more active.

Prolactin is a pituitary hormone involved in the stimulation of milk production, salt and water regulation, growth, development and reproduction. The initial step in its action is the binding to a specific membrane receptor (prolactin receptor) which belongs to the superfamily of class 1 cytokine receptors. The function of the prolactin receptor is mediated, at least in part, by two families of signaling molecules: Janus kinases and signal transducers and activators of transcription. Prolactin (PRL) is a hormone involved in a variety of important functions including ion transport and osmoregulation, stimulation of milk, protein synthesis as well as the regulation of numerous reproductive functions. PRL exerts its influence on different cell types through a signal transduction pathway which begins with the binding of the hormone to a transmembrane PRL receptor. Immunoreactive PRL receptor, a member of the cytokine receptor family, varies in size (short and long forms) with tissue source and species, from ~40 kDa to 100 kDa. The PRL receptor consists of at least three separate domains: an extracellular region with 5 cysteines which contains the prolactin binding site, a single transmembrane domain and a cytoplasmic region, the length of which appears to influence ligand binding and regulate cellular function.

Asialoglycoprotein Receptor 2 (ASGR2) is a hetero-oligomeric protein comprised of major and minor subunits, encoded by different genes. ASGR2 is a subunit of the asialoglycoprotein receptor; it is the less abundant minor subunit. The ASGR2 receptor is a transmembrane protein, which has a crucial role in serum glycoprotein homeostasis by mediating the endocytosis and lysosomal degradation of glycoproteins with exposed terminal galactose or N-acetylgalactosamine residues.

GDNF family receptor alpha-1 (GFRA1) belongs to the GDNF receptor family. GFRA1 is a glycosyl-phosphatidylinositol(GPI)-linked cell surface receptor for both Glial cell line-derived growth factor (GDNF), neurturin (NTN), and mediates activation of the RET tyrosine kinase receptor. The GFRA1 protein is a potent survival factor for central and peripheral neurons, and is vital for the development of kidneys and the enteric nervous system.

S100A8 is a part of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a broad range of cells, and participate in the regulation of cellular processes such as cell cycle progression and differentiation. S100A8 plays a role in the inhibition of casein kinase and as a cytokine. S100A8 altered expression is related with cystic fibrosis disease. S100A8 is a calcium-binding protein that has antimicrobial activity against bacteria and fungi.S100A8 is crucial for resistance towards invasion by pathogenic bacteria. S100A8 up-regulates transcription of genes that are under the control of NF-kappa-B. S100A8 plays a role in the development of endotoxic shock in response to bacterial lipopolysaccharide. S100A8 endorses tubulin polymerization and promotes phagocyte migration and infiltration of granulocytes at sites of wounding. S100A8 takes part as a pro-inflammatory mediator in acute and chronic inflammation and up-regulates the release of IL8 and cell-surface expression of ICAM1.

CXCL14 is involved in immunoregulatory and inflammatory processes. BRAK protein is structurally related to the CXC (Cys-X-Cys) subfamily of cytokines. CXCL14 displays chemotactic activity for monocytes but not for lymphocytes, dendritic cells, neutrophils or macrophages. CXCL14 is involved in the homeostasis of monocyte-derived macrophages.

Dendritic cell and monocyte chemokinelike protein (DMC/CXCL17/VEGF-correlated chemokine 1/VCC1), is a secreted molecule with a size and predicted 3-dimensional folding pattern similar to that of chemokines CXCL8/IL8 and CXCL14/BRAK. CXCL17 is constitutively generated by airway and intestinal epithelium. CXCL17 induces the chemotaxis of quiescent, but not LPS-activated peripheral blood monocytes and dendritic cells, and it also binds these cells specifically. The expression of CXCL17 is increased in endothelial cells when they are induced to form tubes in vitro. CXCL17, CXCL1/GRO and CXCL8/IL8 which have roles in angiogenesis, show significantly correlated expression with that of VEGF in primary lung, breast and esophageal tumors. Therefore, CXCL17 is suggested to have a role in tumor angiogenesis. The mature Rat CXCL17 shares 82%, 71% amino acid sequence identity with mouse, human CXCL17, respectively.

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.

Tripartite Motif Containing 33 (TRIM33) belongs to the tripartite motif family. This motif includes 3 zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. TRIM33 is assumed to be a transcriptional corepressor. TRIM33 functions as an E3 ubiquitin-protein ligase. TRIM33 also promotes SMAD4 ubiquitination, nuclear exclusion and degradation via the ubiquitin proteasome pathway. In addition, TRIM33 inhibits the transcriptional response to TGF-beta/BMP signaling cascade. Furthermore, TRIM33 has a role in the control of cell proliferation.

Fc Fragment Of IgA Receptor, also known as FCAR, is part of the multichain immune recognition receptor family which is the most abundant immunoglobulin in mucosal areas however it is only the second most common antibody isotype in serum. FCAR participates in both pro-and anti-inflammatory responses depending on the state of IgA bound. FCAR is also a vital Fc receptor for neutrophil killing of tumor cells. Once FCAR expressing neutrophils interact with IgA-opsonized tumor cells, the neutrophils not only show antibody-dependent cell-mediated cytotoxicity, but also release the cytokines TNF-α and IL-1β which cause increased neutrophil migration to the site.

Fibroblast growth factors (FGFs) comprise a family of at least eighteen structurally related proteins that are involved in a multitude of physiological and pathological cellular processes, including cell growth, differentiation, angiogenesis, wound healing and tumorgenesis. 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. Four distinct genes encoding closely related FGF receptors, FGF R1 - 4, are known. All four genes for FGF Rs encode proteins with an N-terminal signal peptide, three immunoglobulin (Ig)-like domains, an acid-box region containing a run of acidic residues between the IgI and IgII domains, a transmembrane domain and the split tyrosine-kinase domain. Multiple forms of FGF R1 - 3 are generated by alternative splicing of the mRNAs. A frequent splicing event involving FGF R1 and 2 results in receptors containing all three Ig domains, referred to as the a isoform, or only IgII and IgIII, referred to as the b isoform. Only the a isoform has been identified for FGF R3 and FGF R4. Additional splicing events for FGF R1 - 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). A 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 FGF R1. Mutations in FGF R1 - 3 have been found in patients with birth defects involving craniosynostosis. The complex patterns of expression of these receptors as well as the specificity of their interactions with the various FGF ligand family members are under investigation.

TLR2 belongs to the Toll-like receptor (TLR) family that plays a fundamental role in pathogen recognition and activation of innate immunity. TLRs are highly conserved from Drosophila to humans and share structural and functional similarities. They recognize pathogen-associated molecular patterns (PAMPs) which are expressed on infectious agents, and mediate the production of cytokines necessary for the development of effective immunity. The various TLRs exhibit different patterns of expression. TLR2 is expressed most abundantly in peripheral blood leukocytes, and mediates host response to Gram-positive bacteria and yeast via stimulation of NF-kappaB.

Cluster of Differentiation 244 (CD244/Natural Killer Cell Receptor 2B4) contains 2 Ig-like (immunoglobulin-like) domains. CD244 is a cell surface receptor expressed on natural killer (NK) cells (and some T cells) which mediate non-major histocompatibility complex (MHC) restricted killing. NK-cell and target cells interaction via the CD244 receptor is believed to modulate NK-cell cytolytic activity. CD244 molecules function in eosinophil adhesion and chemotaxis, and have a role in the pathophysiology of allergic rhinitis (AR).

Mouse Complement 5a (C5a) is a glycoprotein which is a member of a family of structurally and functionally related proteins known as anaphylatoxins. C5a is a 77 a.a. peptide created by the C5a convertase proteolytic cleavage of C5 ? chain in the classical and alternative complement pathway (C4b2a3b, C3bBb3b). The mouse C5a has four ? helices and three intrachain disulfide bonds which form a triple loop structure. C5a functions through G-protein coupled receptor (GPCR) (C5aR/CD88). C5a is a effective chemoattractant and anaphylatoxin which functions on all classes of leukocytes and on many other cell types including endothelial, smooth muscle, kidney, liver, and neural cells. Mouse C5a also mediates IL-8 release from bronchial epithelial cells. Furthermore, it triggers an oxidative surge in macrophages and neutrophils, causing the release of histamine in basophils and mast cells. The C5a anaphylatoxin activity on hepatocytes results indirectly from interaction with nonparenchymal cell via prostanoid secretion.

Anthrax toxin receptor 2, also known as ANTXR2, takes part in the configuration of little blood vessels (capillaries). ANTXR2 helps the toxin that leads to anthrax to attach to cells and trigger illness. ANTXR2 is necessary for cellular interactions with laminin and the extracellular matrix.

EDA2R (ectodysplasin A2 receptor) mediates the activation of the NF-kappa-B and JNK pathways. Activation seems to be mediated through binding to TRAF3 and TRAF6. In addition, Mutations in EDA give rise to a clinical syndrome characterized by loss of hair, sweat glands, and teeth. EDA2R specifically binds to EDA-A2 isoform. This protein is a type III transmembrane protein of the TNFR (tumor necrosis factor receptor) superfamily, and contains 3 cysteine-rich repeats and a single transmembrane domain however it lacks an N-terminal signal peptide. Alternatively spliced transcript variants have been found for this gene. Among the diseases associated with EDA2R are ectodermal dysplasia 1, hypohidrotic, x-linked, and hypohidrotic ectodermal dysplasia.

S100A11 is a member of the S100 family of proteins which contains two EF-hand calcium-binding motifs and is thought to be involved in the regulation of a number of cellular processes including cell cycle progression and differentiation. S100A11 may function in motility, invasion and tubulin polymerisation. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21. Chromosomal rearrangements and altered expression of S100A11 have been implicated in tumor metastasis.

The protein kinase A holoenzyme is a heterotetramer composed of two types of subunits: Catalytic and Regulatory. The Catalyticsubunit contains the enzyme's active site. It also contains a domain that binds ATP and a domain that binds the regulatory subunit. The Regulatory subunit consists oftwo molecules which bind one another in an anti-parallel orientation to form a homodimer; for type I subunits- this binding is covalent via disulfide bonds. This subunit also has has two domains that bind cyclic AMP, a domain that interacts with a catalytic subunit, and an "auto-inhibitory" domain that serves as a substrate or pseudosubstrate for the catalytic subunit. Regulatory subunits may also have biologic activity distinct from their role in modulating catalytic subunit activity. Regulatory subunits exist in two major forms, RI and RII, with each form having two subtypes designated alpha and beta. Each of the four isotypes of the regulatory subunit is encoded by a different gene. In addition, three isotypes of the catalytic subunit have been identified (alpha, beta and gamma). The different isotypes tend to have different distributions within cells and among tissues. Type I enzymes inhabit cytoplasmic, soluble fractions of the cell, whereas type II enzymes tend to associate with cellular membranes.

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.

Prolactin-inducible protein (PIP) is a main protein component of benign breast gross cysts. PIP is a famous indicator of breast cancer, since it is found in around 50% of all breast cancer specimens. PIP is expressed in exocrine glands, in pathologic conditions, in breast cysts and breast cancers exhibiting apocrine features. PIP and prostate specific antigen are co-expressed in androgen receptor-positive breast tumours.

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. All VEGF-receptors have seven immunoglobulin-like extracellular domains, a single transmembrane region and an intracellular split tyrosine kinase domain. VEGFR-2 has a lower affinity for VEGF than the Flt-1 receptor, but a higher signaling activity. Mitogenic activity in endothelial cells is mainly mediated by VEGFR-2 leading to their proliferation.
Differential splicing of the flt-1 gene leads to the formation of a secreted, soluble variant of VEGFR-1 (sVEGFR-1). No naturally occuring, secreted forms of VEGFR-2 have so far been reported. The binding of VEGF165 to VEGFR-2 is dependent on heparin.

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. All VEGF-receptors have seven immunoglobulin-like extracellular domains, a single transmembrane region and an intracellular split tyrosine kinase domain. VEGFR-2 has a lower affinity for VEGF than the Flt-1 receptor, but a higher signaling activity. Mitogenic activity in endothelial cells is mainly mediated by VEGFR-2 leading to their proliferation.
Differential splicing of the flt-1 gene leads to the formation of a secreted, soluble variant of VEGFR-1 (sVEGFR-1). No naturally occuring, secreted forms of VEGFR-2 have so far been reported. The binding of VEGF165 to VEGFR-2 is dependent on heparin.

RERG is a 199 amino acid protein which localizes in the cytoplasm and is a member of the Ras subfamily of small GTPases. RERG is expressed in the pancreas, liver, skin, lung, brain, kidney and heart tissue. RERG is a vital mediator of diverse cell signaling pathways, including those leading to cell proliferation, cytoskeletal organization and secretion.

RELM-beta (Resistin-Like Molecule-beta) is a member of a recently identified family of secreted proteins containing a conserved cystein-rich C-terminus. The RELM family consists of resistin (also called FIZZ3), RELM-alfa (FIZZ1), RELM-beta (FIZZ2) and RELM-gamma. Only resisistin and RELM-beta were found in humans whereas all four RELM family members were identified in rodents.
RELM-beta appears to be produced as a homodimer exclusively by intestinal goblet cells and can be found in high quantities in stool. Remarkably, stool of germ-free mice displaying sterile intestinal tract does not contain RELM-beta until bacterial colonization takes place after pathogen-free mice entered natural environment. Some, but not all, colon carcinoma cell lines secrete RELM-beta into the cell culture supernatant.
The physiological function of RELM-beta is not known. High doses of recombinant RELM-beta showed hyperglycemic effects including lowered glucose disposal and increased hepatic glucose production in mice.