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Connective Tissue Growth Factor belongs to the CCN family of proteins. The CCN family presently consists of six members in human also known as: Cyr61 (Cystein rich 61), CTGF (Connective Tissue Growth Factor), Nov (Nephroblastoma Overexpressed gene), WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins). The CCN genes encode secreted proteins associated with the Extracellular Matrix (ECM) and cell membrane.
CCN proteins are matricellular proteins which are involved in the regulation of various cellular functions including: proliferation, differentiation, survival, adhesion and migration. They are expressed in derivatives of the three embryonic sheets and are implicated in the development of kidney, nervous system, muscle, bone marrow, cartilage and bone. During adulthood, they are implicated in wound healing, bone fracture repair, and pathologies such as: fibrosis, vascular ailments and tumorigenesis.
Full length secreted CCN proteins can show an antiproliferative activity, whereas truncated isoforms are likely to stimulate proliferation and behave as oncogenes.
The full length protein consists of four modules: Module I shares partial identity with the N-terminal part of the Insulin-like Growth Factor Binding Proteins (IGFBPs).
Module II includes a stretch of 70amino acid residues – which shares sequence identity with the Von Willebrand Factor Type C repeat (VWC).
Module III contains sequences sharing identity with the Thrombospondin type 1 repeat (TSP1) (WSXCSXXCG), which is thought to be implicated in the binding of sulfated glycoconjugates and to be important for cell adhesion.
Module IV, also designated CT, is encoded by exon5. It is the leasts conserved one of the four domains at the level of nucleotide sequence, but it appears to be critical for several of the biological functions attributed to the CCN proteins. Module IV resembles the CT domain of several extracellular protein including, Von Willebrand's factor and mucins. Sequence similarities to heparin-binding motifs are also found within this domain.
Proteolysis of the secreted full-length CCN proteins that has been reported in the case of CCN2 and CCN3 might result in the production of CCN-derived peptides with high affinity for ligands that full-length CNN proteins bind only poorly. Amino-truncated CCN2 isoforms were biologically active whereas no specific biological activity has been attributed to the truncated CCN3. Although the molecular processes underlying the production of these secreted isoforms is presently unknown, it is important to note that proteolysis occur at the same amino acid residues in both CCN2 and CCN3. An elevated expression of CCN2 has also been detected by Northern blotting in human invasive mammary ductal carcinomas, dermatofibromas, pyogenic granuloma, endothelial cells of angiolipomas and angioleiomyomas, and in pancreatic tumors. A study performed with chondrosarcomas representative of various histological grades established that CCN2 expression was closely correlated with increasing levels of malignancy.
In agreement with CCN2 playing a role in brain tumor angiogenesis, immunocytochemistry studies indicated that both glioblastoma tumor cells and proliferating endothelial cells stained positive for CCN2. In astrocytomas, CCN2 expression was particularly elevated in high grade tumors, with a marked effect of CCN2 on cell proliferation. Downregulation of CCN2 expression in these cells was associated with a growth arrest at the G1/S transition while over-expression of CCN2 induced a two-fold increase of the number of cells in the G1 phase. Gene profiling analysis allowed to identify a set of about 50 genes whose expression might account for the proliferative activity of CCN2 in these cells.
CCN2 was seen in a higher proportion of mononuclear cells of patients with acute lymphoblastic leukemia.

Eukaryotic translation initiation factor 4H (EIF4H) is a 248 amino acid protein which localizes to the perinuclear region of the cytoplasm and is expressed as 2 isoforms, termed short and long. EIF4H functions to stimulate the initiation of protein synthesis at the level of mRNA employment. EIF4H stimulates the RNA-dependent ATP hydrolysis catalyzed by EIF4A and EIF4B. EIF4H gene defects linked to Williams- Beuren syndrome (WBS), a rare developmental disorder characterized by cardiovascular and musculo-skeletal abnormalities and caused by the deletion of contiguous genes at 7q11.23.

Gankyrin (proteasome 26S subunit) is a multicatalytic proteinase oncoprotein commonly overexpressed in most hepatocellular carcinomas. Proteasomes are found throughout eukaryotic cells at a high concentrations and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. Gankyrin interacts with S6 ATPase of the 19S regulatory particle of the 26S proteasome. Gankyrin is involved in theregulation of the phosphorylation of the retinoblastoma protein by CDK4, and to enhance the ubiquitinylation of p53 by MDM2. Gankyrin consists of 7 ankyrin repeats and is structurally similar to I kappa Bs. Gankyrin acts as a regulatory subunit of the 26s proteasome which is involved in the atp-dependent degradation of ubiquitinated proteins. Gankyrin is involved in progression of esophageal squamous cell carcinoma. gankyrin plays an oncogenic role especially in early stages of human epatocarcinogenesis. Gankyrin binds to NF-kappaB and suppresses its activity at the transcription level by modulating acetylation through SIRT1. Structural comparison between Gankyrin & p16(INK4A) identified numerous residues of gankyrin that are potentially important for CDK4 binding.

Extracellular signal-regulated kinases (ERKs) or classical MAP kinases are widely expressed protein kinaseintracellular signalingmolecules which are involved in functions including the regulation of meiosis, mitosis, and postmitotic functions in differentiated cells. Many different stimuli, including growth factors, cytokines, virusinfection, ligands for heterotrimeric G protein-coupled receptors, transforming agents, and carcinogens, activate the ERK pathway. The term, "extracellular signal-regulated kinases", is sometimes used as a synonym for mitogen-activated protein kinase(MAPK), but has more recently been adopted for a specific subset of the mammalianMAPK family. In the MAPK/ERK pathway, Rasactivates c-Raf, followed by MEKand then MAPK1/2 (below). Ras is typically activated by growth hormones through receptor tyrosine kinasesand GRB2/SOS, but may also receive other signals. ERKs are known to activate many transcription factors and some downstream protein kinases. Disruption of th

Pro-Epidermal Growth Factor Isoform 1 or EGF, is a globular peptide (77aa residues) which includes three intra molecular disulfide bonds. This protein acts as a growth factor that mediates the growth and proliferation of different epithelial & epidermal cells. Among other processes that EGF is part of are inhibition of gastric secretion and wound healing. EGF is a ligand for class I tyrosine kinase receptor (c-erbB).

VEGF-C, also known as Vascular Endothelial Growth Factor Related Protein (VRP), is a recently discovered VEGF growth factor family member that is most closely related to VEGF-D. Human VEGF-C cDNA encodes a pre-pro-protein of 416 amino acids residues. It is almost identical to the mouse VEGF-C protein. Similar to VEGF-D, VEGF-C has a VEGF homology domain spanning the middle third of the precursor molecule and long N- and C-terminal extensions. In adults, VEGF-C is highly expressed in heart, placenta, ovary and small intestine. Recombinant human VEGF-C, lacking the N- and C-terminal extensions and containing only the middle VEGF homology domain, forms primarily non-covalently linked dimers. This protein is a ligand for both VEGFR-2/KDR and VEGFR-3/FLT-4. Since VEGFR-3 is strongly expressed in lymphatic endothelial cells, it has been postulated that VEGF-C is involved in the regulation of the growth and/or differentiation of lymphatic endothelium. Although recombinant human VEGF-C is also a mitogen for vascular endothelial cells, it is much less potent than VEGF-A.

TNFRSF14, a member of the TNF receptor superfamily, is a type I transmembrane protein. TNFRSF14 is expressed in peripheral blood T cells, B cells, monocytes and in various tissues enriched in lymphoid cells. TNFRSF14 operates as a co-stimulatory factor for the activation of lymphoid cells and as a deterrent to infection by herpesvirus. Additionally, TNFRSF14 encourages the proliferation of T cells, and triggers apoptosis of various tumor cells.

Gamma-glutamylaminecyclotransferase (A2LD1) is an enzyme which converts gamma-glutamylamines to free amines and 5-oxoproline. A2LD1 demonstrates high activity toward gamma-glutamyl-epsilon-lysine, derived from the breakdown of fibrin and other proteins cross-linked by transglutaminases. A2LD1 assists in the proteolytic degradation of crosslinked fibrin by breaking down isodipeptide L-gamma-glutamyl-L-epsilon-lysine, which is a byproduct of fibrin degradation. The reaction catalyzed by the A2LD1 produces 5-oxo-L-proline and a free alkylamine.

GNAI3 is a member of the G-alpha family and G (i/o/t/z) subfamily which act as modulators or transducers in several transmembrane signaling systems. G(k) is the stimulatory G protein of receptor-regulated K+ channels. The active GTP-bound form inhibits the connotation of RGS14 with centrosomes and is essential for the translocation of RGS14 from the cytoplasm to the plasma membrane. GNAI3 takes part in cell division and is known to cooperate with RIC8A, S1PR1, RGS5, RGS10, RGS12, RGS14, RGS16, RGS18, and RGS19.

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.

Spindle And Kinetochore Associated Complex Subunit 1 (SKA1) is a part of the kinetochore-microtubule interface which associates with microtubules as oligomeric assemblies. The complex facilitates the processive movement of microspheres along a microtubule in a depolymerization-coupled manner. SKA1 is necessary for timely anaphase onset during mitosis, when chromosomes undergo bipolar attachment on spindle microtubules leading to silencing of the spindle checkpoint.

Mitochondrial antiviral signaling protein (MAVS) is vital for innate immune defense against viruses. MAVS is an intermediary protein essential in the virus-triggered IFN-beta signaling pathways. MAVS is involved in activation of transcription factors that regulate expression of IFN-beta and contributes to antiviral immunity.

PCMT1 enzyme catalyses the methyl esterification of L-isoaspartyl and D-aspartyl residues in peptides and proteins that result from spontaneous decomposition of normal L-aspartyl and L-asparaginyl residues. PCMT1 is involved in the repair and/or degradation of damaged proteins.

L1 Cell Adhesion Molecule (L1CAM) which is a cell adhesion receptor of the immunoglobulin superfamily takes part in nerve cell function. L1CAM is a neural cell adhesion molecule involved in the dynamics of cell adhesion and in the generation of transmembrane signals at tyrosine kinase receptors. L1CAM takes part in cell migration, neurite outgrowth and myelination. Furthermore, L1CAM plays an important role in the dynamics of neuronal structure and function in the mature brain.

Neuregulin/Heregulin is a family of structurally related polypeptide growth factors which are stemmed from alternatively spliced genes (NRG1, NRG2, NRG3 and NRG4). Thus far, there are more than 14 soluble and transmembrane proteins derived from the NRG1 gene. Proteolytic processing of the extracellular domain of the transmembrane NRG1 isoforms release soluble growth factors. HRG1-b1 is comprised of an Ig domain and an EGF-like domain which is necessary for direct binding to receptor tyrosine kinases erb3 and erb4. This binding stimulates erb3 and erb4 heterodimerization with erb2, promoting intrinsic kinase activity, which results in tyrosine phosphorylation. Even though HRG1-b1 biological effects are still unclear, it has been discovered to advance motility and invasiveness of breast cancer cells which in addition might entail up-regulation of expression and function of the autocrine motility-promoting factor (AMF).

TNFR1 belongs to the TNF-receptor superfamily. TNFR1 is a receptor for TNFSF2/TNF-alpha and homotrimeric TNFSF1/lymphotoxin-alpha.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.
TNFR1 is capable of signaling both cell survival and apoptosis. TNFR1-induced apoptosis requires 2 sequential signaling complexes. TNFR1 is capable of activating NF-kappaB, mediate apoptosis, and function as a regulator of inflammation. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNFR1 contributes to the induction of non-cytocidal TNF effects including anti-viral state and activation of the acid sphingomyelinase. Human TNFR1 has a major region which controls cell surface expression. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women.
Germline mutations of the extracellular domains of TNFR1 are linked to the autosomal dominant periodic fever syndrome. The impaired receptor clearance is believed to be a mechanism of the disease. Familial hibernian fever (FHF) is caused by defects in TNFRSF1A gene.

Herpesvirus entry mediator or HVEM or tumour necrosis factor receptor superfamily member 14 or TNFRSF14, is part of the TNF receptors family that is a receptor located on the cell surface. The cytoplasmic area of this receptor can bind all sorts of TNF receptor associated factor (TRAF) protein. Those proteins can mediate pathways activating an immune response. The MITF is regulating TNFRSF14 gene expression.

SBDS is part of an extremely preserved protein family which exists from archaea to vertebrates and plants. SBDS protein functions in RNA metabolism and has a role in the biogenesis of the 60S ribosomal subunit and translational activation of ribosomes. Shwachman-Diamond syndrome is a rare autosomal recessive disorder produced by mutations in the SBDS gene.

MTHFS is a cytosolic protein which takes part in the formate metabolic process. MTHFS along with a magnesium cofactor catalyzes the ATP-dependent reaction which reduces 5-formyltetrahydrofolate (5-MTHF) to 5,10-methenyltetrahydrofolate(MTHF). MTHF is the substrate used by MTHFR (methylenetetrahydrofolate reductase) to generate 5-MTHF. In addition, MTHF is a coenzyme used in thymidine biosynthesis by thymidylate synthase (FAD).

Calcium/Calmodulin-Dependent Protein Kinase II Inhibitor 2 (CAMK2N2) is a protein coding gene which regulates cell growth when overexpressed in colon adenocarcinoma LoVo cells. CAMK2N2 plays a role as a cellular inhibitor of CaM-kinase II (CAMK2).

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.

Mesenchymal epithelial transition factor (c-MET) is a proto-oncogenic receptor tyrosine kinase. The endogenous ligand for c-MET is HGF (hepatocyte growth factor), which is a disulfide-linked heterodimeric molecule produced predominantly by mesenchymal cells. In the adult, c-MET protein expression is limited to stem and progenitor cells and is required for wound healing and hepatocyte regeneration. In the embryo, c-MET receptors are expressed on cells of epithelial origin, which are vital for invasive growth and mediate epithelial-mesenchymal transition (EMT). Abnormal activation of the HGF/MET pathway leads to a variety of cancers. c-MET mutation is linked with a poor prognosis since it can trigger tumor growth, angiogenesis and metastasis.

Vascular endothelial growth factor is an important signaling protein involved in both vasculogenesis and angiogenesis. As its name implies, VEGF activity has been mostly studied on cells of the vascular endothelium, although it does have effects on a number of other cell types (e.g. stimulation monocyte/ macrophagemigration, neurons, cancer cells, kidney epithelial cells ). VEGF mediates increased vascular permeability, induces angiogenesis, vasculogenesis and endothelial cell growth, promotes cell migration, and inhibits apoptosis. In vitro, VEGF has been shown to stimulate endothelial cell mitogenesisand cell migration. VEGF is also a vasodilator and increases microvascular permeability and was originally referred to as vascular permeability factor.
Elevated levels of this protein are linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in this gene have been associated with proliferative and nonproliferative diabetic retinopathy.

TGFBR1 is a single-pass type 1 membrane protein which is a part of the TGFB receptor subfamily and the protein kinase superfamily. TGFBR1 is a secreted protein that performs many cellular functions such as the control of cell growth, cell differentiation, cell proliferation and apoptosis. TGFBR1 also controls the immune system and shows different activities on various types of cell, or cells at different developmental stages.