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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.

Killer-cell immunoglobulin-like receptors (KIRs), are a family of cell surface glycoproteins found on Natural Killer (NK) Cells, which are important cells of the immune system. They control the killing function of these cells by interacting with MHC class I molecules, which are expressed on all cell types. This interaction allows them to identify virally infected cells or tumor cells that have a distinctive low level of Class I MHC on their surface. The majority of KIRs are inhibitory, which means that their recognition of MHC suppresses the cytotoxic activity of their NK cell. Only a limited number of KIRs have the capacity to activate cells.
The KIR genes are found in a cluster on chromosome 19q13.4 within the 1 Mb leukocyte receptor complex (LRC). KIR molecules are extremely polymorphic, meaning their gene sequences differ significantly between individuals, so that different individuals have different arrays/repertoires of KIR genes.
The KIR proteins are categorized by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM). Whereas KIR proteins with the short cytoplasmic domain lack the ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals.
KIR2DL1 is an inhibitory Killer Cell Ig-like Receptor (KIR, previously called p58 KIR, p58.1, cl-42, NKAT1, or KIR-K6), which recognizes class I MHC molecules (HLA-Cw2, -Cw4, -Cw5, and Cw6). The extracellular domain of KIR2DL1 was over expressed as insoluble protein aggregates (inclusion bodies).

CCL4L1 (C-C motif chemokine 4-like) is a member of to intercrine beta (chemokine CC) family. The CCL4L1 protein is similar to CCL4 which inhibits HIV replication in peripheral blood monocytes which express CCR5.

LanC Lantibiotic Synthetase Component C-Like 1 (LANCL1) belongs to the LanC family although formerly considered a part of the G-proteincoupled receptor superfamily. LANCL1 takes part in the biosynthesis of antimicrobial peptides. LANCL1 functions as a peptide-modifying enzyme component in eukaryotic cells. LANCL1 participates in EPS8 signaling and binds glutathione.

Leucine Rich Repeat And Ig Domain Containing 1, also known as Lingo1 is primarily expressed in neuronal tissue, and most abundantly in the cortex. In addition, Lingo 1 is involved in the inhibition of axon regeneration all the way through a ternary complex formed with NgR1 (ligand-binding subunit) and p75 (signal transducing subunit). The inhibitory action is accomplished through RhoA-GTP upregulation in response to the presence of MOG, MAG or Nogo-66 in the central nervous system. Furthermore, LINGO-1 inhibits oligodendrocyte precursor differentiation as well as myelination, by a mechanism which also involves activation of RhoA, however it appears that it does not require 75 or NgR1.

RAP1B is a member of a superfamily of RAS-like small GTP-binding proteins which takes part in cell signaling. RAP1B owns an intrinsic GTPase activity and is universally expressed in mammalian tissues. The alleged effector domain of Ras proteins, whose integrity is required for cell transformation as well as interaction with the putative effector protein GAP, is conserved in both Rap 1 proteins.

Ras association domain-containing protein 3 (RASSF3) is a ubiquitously expressed protein found in normal and cancerous tissues. RASSF3 is a member of RASSF family whose members contain a highly conserved Ras association domain (Ral GDS/AF-6 or RA) and function as Ras effectors/tumor suppressors. RASSF3 contains an N-terminal RA domain and a coiled-coil SARAH domain and may have 3 isoforms (RASSF3A, RASSF3B and RASSF3C) due to alternative splicing. RASSF3B and RASSF3C are shorter than RASSF3A and do not contain the RA and SARAH domain.

Rho-related GTP-binding protein RhoB (RhoB) belongs to the Rho GTP-binding protein family. RhoB facilitates apoptosis in neoplastically transformed cells after DNA damage. RhoB has a negative role in tumorigenesis since deletion causes tumor formation.

OSTF1 is an intracellular protein produced by osteoclasts that induces bone resorption, via signaling cascade which results in the secretion of factors enhancing osteoclast formation and activity.

ZFAND3 holds a DNA-binding domain and has a large number of purposes, most of which include certain form of transcriptional activation or repression. ZFAND3 is a 251 aa protein having two AN1-type zinc fingers and two UIM (ubiquitin-interacting motif) repeats. The AN1-type zinc finger domain is conserved in animals and plants and is frequently found in proteins which hold an ubiquitin-like domain, which proposes a part in the ubiquitination pathway.

Chemokine (C-C motif) ligand 7 (CCL7) is a small cytokine known as a chemokine that was previously called monocyte-specific chemokine 3 (MCP3). Due to CCL7 possessing two adjacent N-terminal cysteine residues in its mature protein, it is classified among the subfamily of chemokines known as CC chemokines. CCL7 specifically attracts monocytes, and regulates macrophage function. It is produced by certain tumor cell lines and by macrophages. This chemokine is located on chromosome 17 in humans, in a large cluster containing many other CC chemokines and is most closely related to CCL2(previously called MCP1).

PKLR is a pyruvate kinase which catalyzes the transphosphorylation of phohsphoenolpyruvate into pyruvate and ATP. That is the rate-limiting step of glycolysis. PKLR gene encodes the L- and R-type isoenzymes through alternate splicing events controlled by different promoters. L-type isoform can also appear as a tetramer and is upregulated by glucose with implications in maturity-onset diabetes of the young.

Mitogen-activated protein kinase 1 (MAPK1) is also known as "extracellular signal-regulated kinase 2" (ERK2). Two similar (85% sequence identity) protein kinases were originally called ERK1 and ERK2. They were found during a search for protein kinases that are rapidly phosphorylated after activation of cell surface tyrosine kinasessuch as the epidermal growth factor receptor. Phosphorylation of ERKs leads to the activation of their kinase activity. The molecular events linking cell surface receptors to activation of ERKs are complex. It was found that RasGTP-binding proteins are involved in the activation of ERKs. Another protein kinase, Raf-1, was shown to phosphorylate a "MAPK kinase", thus qualifying as a "MAPK kinase kinase". The MAPK kinase was named "MAPK/ERK kinase" (MEK). Receptor-linked tyrosine kinases, Ras, Raf, MEK and MAPK could be fitted into a signaling cascade linking an extracellular signal to MAPK activation. Transgenic gene knockoutmice lacking MAPK1 have major defects in early development.

REM2 and RAB-Like Small GTPase 1 (RSG1) plays a part in targeted membrane trafficking most likely at the level of vesicle fusion with membranes. The RSG1 protein is involved in cilium biogenesis by regulating the transportation of cargo proteins to the basal body and to the apical tips of cilia. RSG1 is a potential effector of the planar cell polarity signaling pathway. RSG1 is also involved in exocytosis in secretory cells.

Adenylate kinases play a role in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. There are 3 types of adenylate kinase isozymes, AK1, AK2, and AK3 in vertebrates. Expression of these isozymes are tissue-specific and developmentally regulated. AK2 is localized in the mitochondrial intermembrane space and is involved in apoptosis. AK2 is mutated in individuals with reticular dysgenesis.

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.

L antigen family member 3 (LAGE3) is a part of the CTAG family. LAGE3 is ubiquitously expressed in somatic tissues unlike the other family members, which are usually expressed only in testis and activated in a broad range of human tumors. LAGE3 is also highly conserved in mouse and rat, suggesting that the encoded protein is functionally significant.

Mitogen-Activated Protein Kinase Kinase 2 (MAP2K2) is a dual specificity protein kinase, which is a member of the STE grouping of kinases and the MAP kinase kinase family. MAP2K2 is activated by a wide range of growth factors and cytokines and also by membrane depolarization and calcium influx. The MAP2K2 kinase is known for its vital role in mitogen growth factor signal transduction. MAP2K2 phosphorylates and consequently activates MAPK1/ERK2 and MAPK2/ERK3. The activation of the MAP2K2 kinase itself is dependent on the Ser/Thr phosphorylation by MAP kinase kinase kinases. The inhibition or degradation of the MAP2K2 kinase is also found to be involved in the pathogenesis of Yersinia and anthrax. MAP2K2 gene mutations cause cardiofaciocutaneous syndrome (CFC syndrome).

Mitogen-activated protein kinase 1 (MAPK1) is also known as "extracellular signal-regulated kinase 2" (ERK2). Two similar (85% sequence identity) protein kinases were originally called ERK1 and ERK2. They were found during a search for protein kinases that are rapidly phosphorylated after activation of cell surface tyrosine kinasessuch as the epidermal growth factor receptor. Phosphorylation of ERKs leads to the activation of their kinase activity.
The molecular events linking cell surface receptors to activation of ERKs are complex. It was found that RasGTP-binding proteins are involved in the activation of ERKs. Another protein kinase, Raf-1, was shown to phosphorylate a "MAPK kinase", thus qualifying as a "MAPK kinase kinase". The MAPK kinase was named "MAPK/ERK kinase" (MEK).
Receptor-linked tyrosine kinases, Ras, Raf, MEK and MAPK could be fitted into a signaling cascade linking an extracellular signal to MAPK activation.
Transgenic gene knockoutmice lacking MAPK1 have major defects in early development.

RGS2 belongs to the RGS family which are regulatory molecules that act as GTPase activating proteins for G alpha subunits of heterotrimeric G proteins. RGS2 inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits and as a result driving them into their inactive GDP-bound form.

Chemokine (C-X-C motif) ligand 2 (CXCL2) is a small cytokine belonging to the CXC chemokine family that is also called macrophage inflammatory protein 2-alpha (MIP2-alpha), Growth-regulated protein beta (Gro-beta) and Gro oncogene-2 (Gro-2). CXCL2 is 90% identical in amino acid sequence as a related chemokine, CXCL1. This chemokine is secreted by monocytes and macrophages and is chemotactic for polymorphonuclear leukocytes and hematopoietic stem cells. The gene for CXCL2 is located on human chromosome 4 in a cluster of other CXC chemokines. CXCL2 mobilizes cells by interacting with a cell surface chemokine receptor called CXCR2.

RRM2 catalyzes the formation of deoxyribonucleotides from ribonucleotides. Synthesis RRM2 is regulated in a cell-cycle dependent method. RRM2 supplies the precursors essential for DNA synthesis. RRM2 catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides. RRM2 Inhibits Wnt signaling.

CTLA-4 is a member of the immunoglobulin superfamily and encodes a protein which transmits an inhibitory signal to T cells. The protein contains a V domain, a transmembrane domain, and a cytoplasmic tail. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. Mutations in this gene have been associated with insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, and other autoimmune diseases.