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Retinoblastoma (RB) is an embryonic malignant neoplasm of retinal origin. It almost always presents in early childhood and is often bilateral. Spontaneous regression ('cure') occurs in some cases. Retinoblastoma acts as a regulator of other genes and forms a complex with adenovirus e1a and with sv40 large t antigen. Retinoblastoma acts as a tumor suppressor and modulats functionally certain cellular proteins with which t and e1a compete for pocket binding. Retinoblastoma is potent inhibitor of e2f-mediated trans-activation, recruits and targets histone methyltransferase suv39h1 leading to epigenetic transcriptional repression, inhibits the intrinsic kinase activity of taf1.

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.

RPL23A is a ribosomal protein which is a component of the 60S subunit. Ribosomes, the organelles which catalyze protein synthesis, consist of a small 40S subunit and a large 60S subunit. Together these subunits are composed of 4 RNA species and approximately 80 structurally different proteins. RPL23A is a member of the L23P family of ribosomal proteins. It is located in the cytoplasm. Recombinant Human Ribosomal Protein L23A may be one of the target molecules involved in mediating growth inhibition. The corresponding protein binds to a specific site on the 26S rRNA in yeast.

Prorelaxin H2 (RLN2) is a member of the insulin gene superfamily. This family which is produced by the ovary, targets the mammalian reproductive system to ripen the cervix, elongate the pubic symphysis and inhibit uterine contraction. It may also have other roles in boosting sperm motility, regulating blood pressure, controlling heart rate and releasing oxytocin and vasopressin. RLN2 is a peptide hormone linked to several therapeutically relevant physiological effects, including regulation of collagen metabolism and multiple vascular control pathways. The active form of the RLN2 protein consists of an A chain and a B chain linked by disulfide bonds.

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.

Cystatins are a superfamily of cysteine proteinase inhibitors found in both plants and animals. They comprise a group of proteinase inhibitors, widely distributed in tissues and body fluids, and form tight complexes with cysteine proteases such as cathepsin B, H, L and S. Cystatin C, a secreted molecule of this family, is of interest from biochemical, medicine and evolutionary points of view. Cystatin C, with molecular weight of 13260 Da, is composed of 120 amino acids, lacks carbohydrate and has two disulfide bridges located near the carboxyl terminus. Cystatin C is increased in patients with malignant diseases, and is related to the insufficiency of renal function and appears to be a better marker than creatinine. On the other hand, low levels of cystatin C involve cause the breakdown of the elastic laminae and, subsequently, the atherosclerosis and abdominal aortic aneurysm.

Thrombospondin-4 (THBS4) is a member of the thrombospondin protein family. This family members are adhesive glycoproteins that mediate cell-to-cell and cell-to-matrix interactions. THBS4forms a pentamer and binds to heparin and calcium. Among them THBS4binds a variety of matrix proteins including Collagens I, II, III, V, Laminin‑1, Matrilin‑2 and Fibronectin. THBS4 is up‑regulated in the spinal cord following peripheral nerve injury where it contributes to presynaptic hypersensitivity and hyperalgesia and is also up‑regulated in muscle following denervation.

SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid. CXCL12 is strongly chemotactic for lymphocytes and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor.
The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.

U-snRNPs which are a pivotal part of spliceosomes, are created between small non-coding nuclear RNAs and a protein moiety. Whereas the 7 Sm proteins are conserved, the RNP antigens are exclusive for each U-snRNP subclass.

SNUPN is a nuclear import adaptor protein which is part of the Snurportin family.
SNUPN is Localized to the cytoplasm and nucleus and contains an N-terminal IBB domain and a trimethylguanosine (m3G)-cap binding domain. SNUPN binds specifically the terminal 2,2,7-m3G-cap at the 5'' end of U snRNPs and is involved in transport of U snRNPs into the nucleus through an association with Importin β.

RND1 is a Rho-related GTPases that form a separate branch of the Rho family, since they are different in charge, size, and biochemical properties. RND1 is found in the activated GTP-bound form and performs as a negative regulator of actin assembly and of cell adhesion. RND1 assists in regulation of the organization of the actin cytoskeleton as a reaction to extracellular growth factors.

40S ribosomal protein S3 is a member of the S3P family of ribosomal proteins. RPS3 facilitates the formation of the mRNA binding site 3' of the codon in the decoding site. Moreover, RPS3 takes part in DNA damage recognition due to its affinity for abasic sites and 7, 8-dihydro-8-oxoguanine residues and its collaboration with human base excision repair proteins OGG1 and Ref-1. Expression of RPS3 is higher in colon adenocarcinomas and adenomatous polyps compared to adjacent normal colonic mucosa.

RND3 is a small GTPase which is part of the Ras superfamily that controls the association of the actin cytoskeleton in reaction to extracellular growth factors. RND3 activity causes a decrease in stress fibers and an increase in cell migration, at least in part through regulation of the Rho-dependent kinase ROCK1. RND3 inhibits DNA-damage induced apoptosis and cell cycle arrest. RND3 binds GTP and is resistant to Rho-specific GTPase-activating proteins.

Mitochondrial Ribosomal Protein L1 (MRPL1) exists as a component of the 39S ribosomal subunit and operates in conjunction with other MRPs to mediate protein synthesis. Mitochondrial ribosomes consist of a large 39S subunit and a small 28S subunit, both of which are consist of multiple mitochondrial ribosomal proteins (MRPs) that are encoded by nuclear genes and are vital for protein synthesis within mitochondria. MRPL1 exists as 2 isoforms produced by alternative splicing. Isoform 1 of MRPL1 is ubiquitously expressed while isoform 2 is particularly expressed in heart.

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.

SPRY domain-containing SOCS box protein 1 (SPSB1) belongs to the SOCS box protein subfamily. SPSB1 includes a central SPRY domain and a C-terminal SOCS box. Even though, some of the SOCS protein subfamilies function as adaptors for a large family of ubiquitin-protein isopeptide ligases to regulate certain signaling pathways, the function of the SSB subfamily remains to be determined. SPSB1 may have an imperative role in enhancing the HGF-induced Erk-Elk-1-SRE pathway. SPSB1 overexpression exhibited no effect on the basal level or epidermal growth factor-induced SRE-luciferase activity.

Oncostatin M is a member of a cytokine family that includes leukemia-inhibitory factor, granulocyte colony-stimulating factor, and interleukin 6. This gene encodes a growth regulator which inhibits the proliferation of a number of tumor cell lines. It regulates cytokine production, including IL-6, G-CSF and GM-CSF from endothelial cells.

L-Selectin belongs to a family of divalent cation-dependent carbohydrate-binding glycoproteins or adhesion molecules. The L-Selectin molecule is composed of various domains: one homologous to lectins, one to epidermal growth factor, and two to the consensus repeat units found in C3/C4 binding proteins.
L-selectin is expressed constitutively on lymphocytes, monocytes and granulocytes and interacts specifically with carbohydrate groups on activated endothelial cells. L-Selectin may be shed by proteolytic cleavage and circulating levels in biological fluids may be used as an indicator of various pathological conditions. L-Selectin is cleaved by ADAM17.
L-selectin works as a "homing receptor" for leukocytes to enter secondary lymphoid tissues via the high endothelial venules. Ligands present on endothelial cells will attach to leukocytes expressing L-selectin, which causes the leukocytes to become localized at that juncture. The receptor is also located on the cell surfaces of "naive" T cells, which have not yet encountered their particular antigen. This surface expression is lost following the cells activation.

RPL22, a cytoplasmic ribosomal protein, is a member of the L22E family of ribosomal proteins and a component of the 60S subunit. RPL22 binds specifically to Epstein-Barr virus-encoded RNAs (EBERs) 1 and 2.

The retinoid X receptor (RXR) is a pleiotropic nuclear receptor transcription factor that interacts with a variety of nuclear receptor dimeric partner. RXR binds cognate response elements as a homodimer in the presence of its ligand, 9-cis retinoic acid, or as a heterodimer with other members of the nuclear hormone receptor superfamily including retinoic acid receptors (RAR), thyroid hormone receptors (TR), vitamin D receptors and peroxisome proliferators-activated receptors (PPAR). The RXR family includes three different isoforms; RXR a, b, g . Human RXR a gene is localized on 9q34.9 and encodes two major isoforms (RXR a1, RXR a2). The DNA binding domain of RXR (111-228aa) was purified by using conventional column chromatography techniques.

Rho GDP-dissociation inhibitor 1 (ARHGDIA) is a member of the RAS gene superfamily, which encodes small guanine nucleotide exchange (GTP/GDP) factors. ARHGDIA, which is localized to the cytoplasm, inhibits the dissociation of GDP from Rho proteins, thus preventing GTP from binding to and consequently activating Rho proteins. In humans, the ARHGDIA can be phosphorylated at Ser 101 by p21-activated kinase, an event that inhibits its activity and may result in positive feedback regulation of several ARHGDIA target proteins.

RGS10 is a member of the RGS family that regulate molecules which perform as GTPase activating proteins (GAPs) for G alpha subunits of heterotrimeric G proteins. RGS proteins can disengage G protein subunits of the Gi alpha, Go alpha and Gq alpha subtypes. They drive G proteins into their inactive GDP-bound forms. All RGS proteins share a conserved 120-amino acid sequence termed the RGS domain. The nucleus localized RGS10 is associates specifically with the activated forms of the two related G-protein subunits, G-alphai3 and G-alphaz but is unable to cooperate with the structurally and functionally distinct G-alpha subunits.

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.

Speckle-type POZ protein (SPOP) belongs to the Tdpoz family containing one N-terminal MATH (Meprin and TRAF homology) domain and one C-terminal BTB/POZ domain. SPOP inhibits IPF1/PDX1 transactivation of established target promoters, may be by recruiting a repressor complex. SPOP is involved in ubiquitinylation and protein degradation as a result of an interaction with CUL-3.