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Mitogen-activated protein kinase 9 (MAPK9) belongs to the MAP kinase family. MAP kinases function as an integration point for numerous biochemical signals, and are involved in a broad variety of cellular processes such as proliferation, differentiation, transcription regulation and development. MAPK9 targets specific transcription factors, and consequently mediates immediate-early gene expression in response to diverse cell stimuli. As an active dimer, MAPK9 can translocate to the nucleus and control transcription through its effects on c-Jun, ATF-2, and other transcription factors. MAPK9 blocks the ubiquitination of tumor suppressor p53, and so it increases the stability of p53 in nonstressed cells.

FHIT is a member of the histidine triad gene family. FHIT gene encodes a diadenosine 5',5'''-P1,P3-triphosphate hydrolase involved in purine metabolism. FHIT gene includes the common fragile site FRA3B on chromosome 3, where carcinogen-induced damage can lead to translocations and abnormal transcripts of this gene. The FHIT protein is a tumor suppressor with reduced or no expression in numerous types of cancer. FHIT may also act as a tumor suppressor in normal cells. Alterations and deletions of the FHIT (Fragile Histidine Triad) gene are strongly linked to the genesis and establishment of human tumors of the lung, cervix, breast, colon, stomach, and pancreas. The expression of FHIT is more often lost in cancers of individuals with familial mutations causing deficiency in DNA repair genes such as BRCA1, BRCA2 and MSH2. In vitro FHIT functions as a hydrolase that cleaves diadenosine triphosphate (Ap3A) to ADP and AMP. The FHIT -Ap3A enzyme-substrate complex seems to be the tumor suppressor signal. The restoration of FHIT expression in FHIT -deficient cancer cells leads to apoptosis, involving the intrinsic caspase pathway, in cancer-derived cells and in tumor xenografts.

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.

Cold shock domain-containing protein C2 (CSDC2) is RNA-binding factor that binds specifically to the very 3'-UTR ends of both histone H1 and H3. 3 mRNAs encompass the polyadenylation signal. The CSDPs (cold shock domain containing proteins) are one group of the evolutionarily conserved nucleic acid-binding proteins extensively distributed in bacteria, plants, animals, and involved in a variety of cellular processes, including adaptation to low temperature, cellular growth, nutrient stress and stationary phase. CSDC2 has a central role in the negative regulation of histone variant synthesis in the developing brain.

The C3c component is central in both complement activation pathways, with different specific proteolytic systems cleaving it to form C3 convertase. Cleavage of C3 releases C3a and the C3b fragment which is part of the alternative C3 convertase. C3 levels can be low because of decreased synthesis or due to consumption. High C3 levels are seen in highly acute or chronic inflammation, hepatic cholestasis and during the third trimester of pregnancy.
Unwanted complement activation is a major cause of tissue damage in various pathological conditions and contributes to quite a few immune complex diseases.
Compstatin is an effective inhibitor of the activation of complement component C3 and thus blocks a central and essential step in the complement cascade. The specific binding site on C3, the configuration in the bound form, and the exact mode of action of compstatin are unknown. The crystal structure of compstatin in complex with C3c reveals that the compstatin-binding site is formed by the macroglobulin (MG) domains 4 and 5. This binding site is part of the structurally stable MG-ring created by domains MG1–6 and is distant from any other known binding site on C3. Compstatin does not modify the conformation of C3c, while compstatin itself undergoes a large conformational alteration upon binding.

The protein encoded by this gene is a cytokine that regulates T and natural killer cell activation and proliferation. This cytokine and interleukine 2 share many biological activities. They are found to bind common hematopoietin receptor subunits, and may compete for the same receptor, and thus negatively regulate each other's activity. The number of CD8+ memory cells is shown to be controlled by a balance between this cytokine and IL2. This cytokine induces the activation of JAK kinases, as well as the phosphorylation and activation of transcription activators STAT3, STAT5, and STAT6. Studies of the mouse counterpart suggested that this cytokine may increase the expression of apoptosis inhibitor BCL2L1/BCL-x(L), possibly through the transcription activation activity of STAT6, and thus prevent apoptosis. Two alternatively spliced transcript variants of this gene encoding the same protein have been reported.

COMM domain-containing protein 9 (COMMD9), is a part of the COMMD family. The COMMD family is a group of evolutionary conserved proteins that share a common COMM domain at their extreme C-terminus, which provides an interface for protein-protein interactions. COMMD9 is a 198 amino acid ubiquitously expressed protein which contains one COMM domain and involved in signaling events all over the cell.

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. KIR2DL3 is an inhibitory Killer Cell Ig-like Receptor (KIR, previously called p58 KIR, cl-6, NKAT2 or KIR-K7), which recognizes class I MHC molecules (HLA-Cw1, -Cw3, -Cw7, and Cw8). KIR2DL3 inhibits the activity of NK cells thus preventing cell lysis.

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.

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, IGFBP-3, IGFBP-5, casein, gelatin, 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.

IL15RA, also known as Interleukin 15 Receptor Alpha, is a high-affinity receptor for interleukin-15. IL15RA plays a role as a heterotrimer with the IL-2 receptor beta and gamma subunits to commence signal transduction. IL15/IL15R alpha complexes can transmit reverse signaling which promotes cellular adhesion, tyrosine phosphorylation of intracellular proteins, as well as cytokine secretion by the IL‑15/IL15R alpha expressing cells.

Collagen triple helix repeat-containing protein 1 or CTHRC1 acts as a negative regulator of collagen matrix deposition. The protein is secreted from a 28kDa protein which is glycosylated and very conserved from lower chordates to mammals. CTHRC1 is found qualitatively in plasma of healthy human subjects. CTHRC1 plasma levels are also significantly elevated during pregnancy, in diabetes, in inflammatory and infectious conditions, in subjects with acute myeloid leukemia but not in subjects with solid cancers.CTHRC1 is highly connected with calcified tissues and cartilaginous matrix, but not with endothelial cells.

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.

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.

The protein encoded by this gene is a cytokine that regulates T and natural killer cell activation and proliferation. This cytokine and interleukine 2 share many biological activities. They are found to bind common hematopoietin receptor subunits, and may compete for the same receptor, and thus negatively regulate each other's activity. The number of CD8+ memory cells is shown to be controlled by a balance between this cytokine and IL2. This cytokine induces the activation of JAK kinases, as well as the phosphorylation and activation of transcription activators STAT3, STAT5, and STAT6. Studies of the mouse counterpart suggested that this cytokine may increase the expression of apoptosis inhibitor BCL2L1/BCL-x(L), possibly through the transcription activation activity of STAT6, and thus prevent apoptosis. Two alternatively spliced transcript variants of this gene encoding the same protein have been reported.

GALE is an enzyme that participates as the third enzyme in the Leloir pathway of galactose metabolism. GALE is a homodimeric epimerase localized in bacterial, plant, and mammalian cells. GALE inhances the reverse chemical reaction, the conversion of UDP-glucose to UDP-galactose. UDP-galactose builds galactose-containing proteins and fats, which have a crucial part in chemical signaling, building cellular structures, transporting molecules, and producing energy.

CFL2 protein is a member of the actin-binding proteins ADF family which contains 1 ADF-H domain. Cofilin is a broadly distributed intracellular actin-modulating protein which binds and depolymerizes filamentous F-actin and inhibits the polymerization of monomeric G-actin in a pH-dependent manner. Defects in the CFL2 gene are the cause of nemaline myopathy type 7 (NEM7).

15 KDa Selenoprotein (SEP15) is a protein-coding gene which contains a selenocysteine (Sec) residue at its active site. Theselenocysteine is encoded by the UGA codon that usually signals translation termination. The 3' UTR ofselenoprotein genes have a conventional stem-loop structure, the sec insertion sequence (SECIS), which isnecessary for the recognition of UGA as a Sec codon rather than as a stop signal. Studies in mouse propose thatthis selenoprotein may have redox function and may be implicated in the quality control of protein folding. This geneis localized on chromosome 1p31, a genetic locus usually mutated or deleted in human cancers.Diseases associated with SEP15 include lung cancer susceptibility, and chronic lymphocytic leukemia.

SELPLG glycoprotein functions as a high affinity counter-receptor for the cell adhesion selectin molecules (P, E and L) located in stimulated T lymphocytes and myeloid cells. SELPLG binds leukocytes to activated platelets or endothelia expressing selectins, a vital role in leukocyte trafficking throughout inflammation. In order to have a high-affinity binding activity SELPLG needs two post-translational modifications, tyrosine sulfation and the addition of the sialyl Lewis x tetrasaccharide (sLex) to its O-linked glycans. Polymorphisms and abnormal expression of SELPLG are linked to defects in the innate and adaptive immune response. Alternate splicing results in multiple transcript variants.

Complement Component 4 Binding Protein, Beta (C4BPB) belongs to a superfamily of proteins composed primarily of tandemly arrayed short consensus repeats of approximately 60 amino acids. C4BPB has a regulatory role in the coagulation system also, mediated via the beta-chain binding of protein S, a vitamin K-dependent protein which functions as a cofactor of activated protein C. A single, unique beta-chain of the C4BPB assembles with 7 identical alpha-chains into the principal isoform of C4BPB, which is a multimeric protein that controls activation of the complement cascade via the classical pathway. C4BPB binds as a cofactor to C3b/C4b inactivator (C3bINA), which subsequently hydrolyzes the complement fragment C4b. In addition, C4BPB accelerates the degradation of the C4bC2a complex (C3 convertase) by detaching the complement fragment C2a. Furthermore, C4BPB interacts with anticoagulant protein S and with serum amyloid P component.

UCHL1 (PGP9.5) belongs to a gene family whose products hydrolyze small C-terminal adducts of ubiquitin to produce the ubiquitin monomer. Protein Gene Product (PGP9.5) is a neuron specific protein, structurally and immunologically distinct from neuron specific enolase. Human UCHL1 and UCHL3 have an extremely complicated knot structure for a protein, with five knot crossings. It is considered that the knot structure may increase a protein's resistance to degradation in the proteasome.
The protein, which has a molecular weight of 27 kDa was first defined by high resolution two dimetional PAGE. Standard immunohistochemical techniques have demonstrated the presence of PGP9.5 in neurons and nerve fibers at all levels of the central and peripheral nervous system, in many neurodcrine cells, in segments of the renal tubules, in spermatogonia and leydig cells of the testis, in ova and in some cells of both the pregnant and non pregnant corpus luteum. A point mutation (I93M) in UCHL1 is implicated as the cause of Parkinson's disease in one kindred. On the other hand, a polymorphism (S18Y) in UCHL1 has been found to be associated with a reduced risk for Parkinson's disease. Furthermore, UCHL1 is associated with the Alzheimer's disease, and required for normal synaptic and cognitive function.

Low affinity immunoglobulin gamma Fc region receptor III-A (FCGR3A) is a receptor for the Fc portion of immunoglobulin G, and is involved in the elimination of antigen-antibody complexes from the circulation, as well as other antibody-dependent responses. FCGR3A needs to associate with the gamma subunit of Fc epsilon. The FCGR3A receptor is expressed on natural killer (NK) cells as an integral membrane glycoprotein anchored through a transmembrane peptide, while FCGR3B is expressed on polymorphonuclear neutrophils (PMN) where the receptor is anchored through a phosphatidylinositol (PI) linkage. In addition, FCGR3A is expressed on macrophages, subpopulation of T-cells, immature thymocytes and placental trophoblasts. FCGR3A mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. FCGR3A gene mutations are linked with susceptibility to recurrent viral infections, susceptibility to systemic lupus erythematosus, and alloimmune neonatal neutropenia.