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The epidermal growth factor receptor (EGF R) subfamily of receptor tyrosine kinases comprises four members: EGF R (also known as HER1, ErbB1 or ErbB), ErbB2 (Neu, HER-2), ErbB3 (HER-3), and ErbB4 (HER-4). All family members are type I transmembrane glycoprotein that has an extracellular domain which contains two cysteine-rich domains separated by a spacer region that is involved in ligand-binding, and a cytoplasmic domain which has a membrane-proximal tyrosine kinase domain and a C-terminal tail with multiple tyrosine autophosphorylation sites. The human EGF R gene encodes a 1210 amino acid (aa) residue precursor with a 24 aa putative signal peptide, a 621 aa extracellular domain, a 23 aa transmembrane domain, and a 542 aa cytoplasmic domain. EGF R has been shown to bind a subset of the EGF family ligands, including EGF, amphiregulin, TGF-a , betacellulin, epiregulin, heparin-binding EGF and neuregulin-2 in the absence of a co-receptor. Ligand binding induces EGF R homodimerization as well as heterdimerization with ErbB2, resulting in kinase activation, tyrosine phosphorylation and cell signaling. EGF R can also be recruited to form heterodimers with the ligand-activated ErbB3 or ErbB4. EGF R signaling has been shown to regulate multiple biological functions including cell proliferation, differentiation, motility and apoptosis. In addition, EGF R signaling has also been shown to play a role in carcinogenesis.

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.

ARL6 is a member of the ARF family of GTP-binding proteins. ARL6 has a vital part in modulating membrane trafficking and cytoskeletal functions. Mutation in ARL6 is the source of Bardet-Biedl syndrome (BBS3) which is a pleiotropic genetic disorder that causes obesity, photoreceptor degeneration, polydactyly, hypogenitalism, renal abnor-malities and developmental delay.

TCEB1 (elongin C) is a subunit of elongin, which is a common transcription elongation factor that increases the RNA polymerase II transcription elongation past template encoded arresting sites. The SIII complex is comprised of elongins A/A2, B and C. The SIII complex activates elongation by RNA polymerase II by curbing transient pausing of the polymerase at numerous sites within transcription units. Elongin A acts as the transcriptionally active component of the SIII complex, while elongins B and C are regulatory subunits. Elongin A2 is specifically expressed in the testis, and able to forming a stable complex with elongins B and C. The VHL (von Hippel-Lindau) tumor suppressor protein binds to elongins B and C, and thus inhibits transcription elongation.

Yip1 Interacting Factor Homolog B (YIF1b) is a member of the YIF1 family.

CNTF is a polypeptide hormone whose actions appear to be restricted to the nervous system where it promotes neurotransmitter synthesis and neurite outgrowth in certain neuronal populations. The protein is a potent survival factor for neurons and oligodendrocytes and may be relevant in reducing tissue destruction during inflammatory attacks. A mutation in this gene, which results in aberrant splicing, leads to ciliary neurotrophic factor deficiency, but this phenotype is not causally related to neurologic disease. In addition to the predominant monocistronic transcript originating from this locus, the gene is also co-transcribed with the upstream ZFP91 gene. Co-transcription from the two loci results in a transcript that contains a complete coding region for the zinc finger protein but lacks a complete coding region for ciliary neurotrophic factor.
CNTF is a survival factor for various neuronal cell types. Seems to prevent the degeneration of motor axons after axotomy.

Eukaryotic translation elongation factor 1 delta (EEF1D) is a subunit of the elongation factor-1 complex that is responsible for the enzymatic transport of aminoacyl tRNAs to the ribosome. EEF1D functions as guanine nucleotide exchange factor. EEF1D interacts with HIV-1 Tat, and consequently represses the translation of host-cell, but not HIV-1, mRNAs. EEF1D overexpression is linked to oesophageal carcinoma and may negatively influence the outcome of medulloblastomas.

Glia Maturation Factor-Beta (GMF-Beta) is a 17 kDa protein nerve gorwth factor identified as a growth and differentiation factor in the vertebrate brain.

Glia Maturation Factor-Beta stimulates differentiation of normal neurons as well as glial cells. GMFB inhibits the proliferation of the N-18 neuroblastoma line and the C6 glioma line while promoting their phenotypic expression.
GMF-beta inhances the phenotypic expression of glia & neurons thus inhibits the proliferation of their respective tumors when added to cell culture. Although astrocytes produce GMF-b and stores it inside the cells, they don’t secrete the GMF-B into the cultured medium. Cell- surface GMFb acts on the target cells at close range when cells are in direct contact. GMF-Beta is produced by thymic epithelial cells and plays an important role in T cell development in favor of CD4+ T cells.
GMF-Beta is a brain-specific protein which belongs to the actin-binding proteins (ADF) family. GMF-beta appears to play a role in the differentiation, maintenance, and regeneration of the nervous system. It also supports the progression of certain auto-immune diseases, possibly through its ability to induce the production and secretion of various pro-inflammatory cytokines.

Acidic fibroblast growth factor is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. This protein functions as a modifier of endothelial cell migration and proliferation, as well as an angiogenic factor. It acts as a mitogen for a variety of mesoderm- and neuroectoderm-derived cells in vitro, thus is thought to be involved in organogenesis. Three alternatively spliced variants encoding different isoforms have been described. The binding growth factors are angiogenic agents in vivo and are potent mitogens for a variety of cell types in vitro. There are differences in the tissue distribution and concentration of these 2 growth factors.

Matrix metalloproteinase-7 (MMP-7) also known as matrilysin and PUMP (EC 3.4.24.23) cleaves a number of substrates including collagen types IV and X, elastin, fibronectin, gelatin, laminin and proteoglycans. MMP-7 is closely related to the stromelysin family members but is encoded by a different gene. MMP-7 is the smallest of all the MMPs consisting of a pro-peptide domain and a catalytic domain. It lacks the hemopexin-like domain common to other members of the MMPs. MMP-7 is secreted as a 28 kDa proenzyme and can be activated in vitro by organomercurials and trypsin and in vivo by MMP-3 to a 18 kDa active MMP-7 enzyme. Once activated, MMP-7 can activate pro-MMP-1 and pro-MMP-9 but not pro-MMP-2. MMP-7 is widely expressed having been reported in elevated levels in cycling endometrium as well as in colorectal cancers and adenomas, hepatocellular carcinomas, rectal carcinomas, and approximately 50% of gliomas.

Succinate Dehydrogenase Complex Assembly Factor 2 (SDHAF2) is a mitochondrial protein required for the flavination of a succinate dehydrogenase complex subunit essential for activity of the complex. DHAF2 is necessary for insertion of FAD cofactor into SDHA, the catalytic subunit of succinate dehydrogenase (SDH). SDH is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q). SDHAF2 gene defects are the cause of hereditary paragangliomas type 2 (PGL2), otherwise known as familial non-chromaffin paragangliomas type 2.

Leucine Zipper Transcription Factor-Like 1, also known as LZTFL1 is a ubiquitously expressed protein which localizes to the cytoplasm. LZTFL1 interacts with Bardet-Biedl Syndrome proteins (BBS) and during its interaction with BBS protein complexes, regulates protein trafficking to the ciliary membrane. Nonsense mutations in LZTFL1 cause a form of Bardet-Biedl Syndrome; a ciliopathy characterized partly by polydactyly, obesity, cognitive impairment, hypogonadism, and kidney failure. LZTFL1 also acts as a tumor suppressor; possibly by interacting with E-cadherin as well as the actin cytoskeleton and in this manner regulating the transition of epithelial cells to mesenchymal cells.

SPINT2 is a transmembrane protein acts as an inhibitor of HGF activator. SPINT2 inhibits plasmin, plasma and tissue kallikrein, and factor XIa. SPINT2 has two extracellular Kunitz domains that inhibit few serine proteases. SPINT2 is assumed tumor suppressor, mutations in SPINT2 leads to a congenital sodium diarrhea.

IGF-1 (Insulin-like growth factor-1) is a major hormonal mediator of statural growth. Under regular circumstances, GH (growth hormone) binds to its receptor in the liver, and other tissues, and stimulates the synthesis/secretion of IGF-1. In target tissues, the Type 1 IGF receptor, that is homologous to the insulin receptor, is activated by IGF-1, leading to intracellular signaling which stimulates multiple processes leading to statural growth. IGF-1 metabolic actions are partly directed at stimulating the uptake of glucose, fatty acids, and amino acids so that metabolism supports growing tissues.

ARL2 is a member of the ADP-ribosylation factor (ARF) family. ARL2 functions as a component of a secretory pathway which is involved in the Ca2-dependent release of acetylcholine. ARL2 has a role in the folding of tubule proteins, thus playing a significant role in microtubule dynamics and cell cycle progression. Unlike other members of the ARF family, ARL2 doesn’t act as an activator of the catalytic subunit of cholera toxin.

PTX3 is part of the pentraxin family sharing the C-terminal domain with short pentraxins and containing a unique N-terminal domain. PTX3 is produced and released at inflammatory sites by various cell types including monocytes/macrophages, endothelial cells, vascular smooth muscle cells, fibroblasts, and adipocytes. PTX3 is involved in the regulation of innate resistance to pathogens, inflammatory reactions, possibly clearance of self-components and female fertility. PTX3 is used as a marker for disease activity of psoriasis. High serum PTX3 levels are associated with the disease severity of systemic sclerosis. Elevated serum PTX3 is associated with pulmonary fungal infections.

The type II transmembrane protein FASLG is a member of the tumor necrosis factor (TNF) superfamily. A fas ligand/receptor interaction has a significant part in the regulation of the immune system and the advancement of cancer. FASLG is expressed on the activated T cell surface as a nondisulfidelinked homotrimer. FASLG binding to Fas/CD95/TNFRSF6 on a nearby cell prompts apoptosis in the Fas expressing cell. FASLG is released from the cell surface by metalloproteinases as a soluble molecule that stays trimeric and is able to bind with Fas, but its capability to activate apoptosis is radically reduced. In addition, FASLG binds to DcR3 - a soluble trap receptor with no signal transduction capabilities. Flawed Fas-mediated apoptosis causes oncogenesis in addition to drug resistance in existing tumors. Constitutive expression of FASLG in a variety of tumors enables their immune evasion. Both mouse and human FASLG are active on mouse and human cells.

EFNA1 belongs to the ephrin (EPH) family. The EPH subfamily is the biggest group of receptor protein kinases and they take part in vital nervous system function and development.

ADP-Ribosylation Factor Interacting Protein 1 (ARFIP1) contains 1 AH domain and is a putative target protein of ADP-ribosylation factor.

MMP-1 (interstitial collagenase) can break down a wide range of substrates including types I, II, III, VII, VIII, and X collagens as well as L-Selectin, pro-TNF, IL-1?, IGFBP-3, IGFBP-5, casein, gelatin, ?1 antitrypsin, myelin basic protein, pro-MMP2 and pro-MMP9. A significant function of MMP-1 is the degradation of fibrillar collagens in extracellular matrix remodeling. MMP-1 is expressed in fibroblasts, keratinocytes, endothelial cells, monocytes and macrophages. MMP1 can be divided into a number of distinct domains: a prodomain which is cleaved on activation, a catalytic domain containing the zinc binding site and a short hinge region with a carboxyl terminal domain. MMP1 is part of a cluster of MMP genes which localize to chromosome 11q22.3.

Mimitin (NDUFAF2) is a member of the complex I NDUFA12 subunit family.NADH dehydrogenase is an enzyme located in the inner mitochondrial membrane, which catalyzes the transfer of electrons from NADH to coenzyme Q (CoQ). NDUFAF2 is the "entry enzyme" of oxidative phosphorylation in the mitochondria. Mimitin protein functions as a molecular chaperone for mitochondrial complex I assembly.

STAT1 is a member of the Signal Transducers and Activators of Transcriptionfamily of transcription factors. STAT1 is involved in upregulating genes due to a signal by either type Ior type IIinterferons. In response to IFN-?stimulation, STAT1 forms homodimers or heterodimers with STAT3that bind to the GAS (Interferon-Gamma Activated Sequence) promoter element; in response to either IFN-? or IFN-?stimulation, STAT1 forms a heterodimer with STAT2that can bind the ISRE (Interferon Stimulated Response Element) promoter element. In either case, binding of the promoter element leads to an increased expression of ISG (Interferon Stimulated Genes).

FGF22 is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities and are involved in a variety of biological processes including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. The mouse homolog of this gene was found to be preferentially expressed in the inner root sheath of the hair follicle, which suggested a role in hair development.