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Major Histocompatibility Complex Class II DR Beta 1 also known as HLA-DRB1 ia a member of the HLA class II beta chain paralogs. Molecule class II is a heterodimer consisting of an alpha (DRA) and a beta chain (DRB), both anchored in the membrane. HLA-DRB1 takes an essential part in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). Furthermore, the beta chain is approximately 26- 28 kDa. It is encoded by 6 exons. While exon one encodes the leader peptide; exons 2 and 3 encode the two extracellular domains; exon 4 encodes the transmembrane domain; and exon 5 encodes the cytoplasmic tail.

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).

Truncated BH3 interacting domain death agonist is a truncated form of the pro-apoptotic full-length BID. Truncated BH3 interacting domain death agonist is generated by Caspase-8 cleavage of BID. The truncated form of the protein translocates from the cytosol to mitochondria and transduces apoptotic signals.
BID is a pro-apoptotic Bcl-2 protein having only the BH3 domain. In reaction to apoptotic signaling, BID interacts with another Bcl-2 family of cell death regulators, called Bax, they form a heterodimer resulting to the insertion of Bax into the outer mitochondrial membrane. Bax induces the opening of the mitochondrial voltage-dependent anion channel which lead to the release of cytochrome c and other pro-apoptotic factors from the mitochondria resulting in activation of caspases. BID is a mediator of mitochondrial damage induced by caspase-8 (CASP8). CASP8 cleaves BID, and the COOH-terminal part translocates to mitochondria where it triggers cytochrome c release. The major proteolytic product p15 BID releasea cytochrome c. Isoform 1, Isoform 2 and Isoform 4 induce ice-like proteases and apoptosis while Isoform 3 does not induce apoptosis.

Nucleophosmin (NPM1) is a phosphoprotein which shuffles between the nucleus and the cytoplasm. NPM1 is assumed to be involved in a number of processes including regulation of the ARF/p53 pathway. Several genes fusion partners have been described, particularly the anaplastic lymphoma kinase gene on chromosome 2. NPM1 gene mutations are linked with acute myeloid leukemia.

BUD31 is a member of the BUD31 (G10) family. BUD31 is a nuclear protein which contains a putative nuclear translocation sequence, an N-terminal acidic domain and a cysteine-rich C-terminal domain containing a putative Zinc-finger structure. Based on the structure of BUD31 it is suggested that BUD31 might be a nuclear regulator of transcription.

Synaptobrevin 2 which is an 18 kDa integral membrane protein localized to the cytoplasmic surface of synaptic vesicle, consists of a proline-rich N-terminal region, a highly conserved hydrophilic domain, followed by a transmembrane anchor and a C-terminal. Synaptobrevin 2 is predominantly expressed in Langerhans islets and glomerular cells. The N-terminal domain of the protein (residues 1-89) forms a specific SNARE complex with the target membrane-associated t- or Q-SNAREs syntaxin 1 and SNAP-25.

Small nuclear ribonucleoprotein complexes (abbreviated as U-snRNP) are essential for splicing of precursor mRNA molecules. U1-snRNP is the most abundant RNP particle in the nucleus and consists of one small uridylate-rich RNA (U1 RNA) complexed with several proteins: the three 68/70 kDa, A, C polypeptides are unique to the U1-snRNP particle, whereas 7 so-called Sm proteins (B/B', D1, D2, D3, E, F, G) form a core subparticle that is common to all U-snRNP complexes.
Both the U1-specific proteins and the Sm core particle are targets of autoantibodies which classically have been called the RNP and RNP-Sm specificities, respectively. A clean diagnostic distinction of these specificities has been complicated by the biochemical difficulties of producing clean subparticle fractions from native sources. The use of single recombinant proteins as antigenic targets guarantees a much higher sensitivity and specificity and is the only way to determine RNP antibodies sensu stricto without the disturbing influence of Sm antigens; also with single U1 proteins antibodies will be detected which can be missed because of steric hindrance when using the RNP-Sm complex in an assay.
Autoantibodies to U1-snRNP are present in 95% of patients with Mixed Connective Tissue Disease (MCTD) and 30% of patients with SLE. Antibodies against the 68/70 kDa protein are known to have a high clinical significance in MCTD patients. The 68/70 kDa nomenclature of this protein refers to the fact that different splice variants of the protein are found in human cells.

Prohibitin (PHB) is an evolutionarily conserved gene that is ubiquitously expressed and which Mutations have been linked to sporadic breast cancer. PHB is thought to be a negative regulator of cell proliferation and may be a tumor suppressor. Prohibitin is expressed as two transcripts with changeable lengths of 3' untranslated region. The longer transcript is present at higher levels in proliferating tissues and cells, proposing that this longer 3' untranslated region functions as a trans-acting regulatory RNA.

General Transcription Factor IIH Polypeptide 5 (GTF2H5) is a subunit of transcription/repair factor TFIIH, which serves in gene transcription and DNA repair. GTF2H5 protein stimulates ERCC3/XPB ATPase activity which triggers DNA opening during DNA repair, and is involved in the regulation of cellular levels of TFIIH. GTF2H5 gene mutations result in trichothiodystrophy, complementation group A.

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.

RERG is a 199 amino acid protein which localizes in the cytoplasm and is a member of the Ras subfamily of small GTPases. RERG is expressed in the pancreas, liver, skin, lung, brain, kidney and heart tissue. RERG is a vital mediator of diverse cell signaling pathways, including those leading to cell proliferation, cytoskeletal organization and secretion.

Cysteine protease ATG4B (ATG4B) belongs to the autophagin protein family. Autophagy is the manner by which endogenous proteins and damaged organelles are destroyed intracellularly. Autophagy is vital for cell homeostasis and cell remodeling during differentiation, metamorphosis, non-apoptotic cell death, and aging. ATG4B is a cysteine protease necessary for autophagy, which cleaves the C-terminal part of either MAP1LC3, GABARAPL2 or GABARAP, allowing the liberation of form I. A subpopulation of form I is then transformed to a smaller form (form II). Form II, with an exposed C-terminal glycine, is deemed to be the phosphatidylethanolamine (PE)-conjugated form, and is capable of binding to autophagosomes. Reduced levels of autophagy are seen in some malignant tumors; therefore autophagy may have a role in controlling the unregulated cell growth linked to cancer.

SecB, a significant chaperone that takes part in protein export, binds various ligands rapidly with high affinity and low specificity. SecB plays an important role during protein export through the general secretory pathway by modulating the partitioning of precursors between folding or aggregation and delivery to the membrane-bound translocation apparatus. SecB has the potential to take part in functions outside of export acting as a universal nonspecific chaperone to provide buffering capacity of the nonnative state of proteins in the cytosolic pool.

Lymphotoxin Beta Receptor, also known as LTBR takes part in signaling during the development of lymphoid and other organs, lipid metabolism, immune response, and programmed cell death. In addition, the activity of this receptor has been associated to carcinogenesis. Alternatively spliced transcript variants encoding multiple isoforms have been observed for LTBR.

C11ORF31 (Chromosome 11 Open Reading Frame 31) is a selenoprotein, which contains a selenocysteine (Sec) residue at its active site. The selenocysteine is encoded by the UGA codon which ordinarily signals translation termination. The 3' UTR of selenoprotein genes have a mutual stem-loop structure, the sec insertion sequence (SECIS), which is essential for the recognition of UGA as a Sec codon rather than as a stop signal. The exact function of the C11ORF31 gene is not known, however, selenoproteins are assumed to be responsible for most biomedical effects of dietary selenium. C11ORF31 is involved in a redox-related process.

High mobility group protein HMG-I/HMG-Y (HMGA1) belongs to the non-histone chromosomal high mobility group protein (HMG) family. HMGA1 is composed of a highly conserved AT-hook DNA-binding domain which mediates binding to AT-rich sequences in the minor groove of chromosomal DNA. HMGA1 functions as an architectural chromatin-binding transcription factor modifying the conformation of DNA by modulating nuclear protein-DNA complexes. Furthermore, HMGA1 is involved in numerous cellular processes including growth regulation, viral induction of beta-IFN gene and regulation of inducible gene transcription.

TRAF2 protein is related with transduce signals from members of the TNFR superfamily. TRAF2 is located in the cytoplasm binds to TRAF1, TRAF2, or TRAF3, thus inhibiting TRAF function by sequestering the TRAFs in a suppressed state in the cytoplasm. Overexpression of TANK inhibits TRAF2-mediated NF-Kappa-B activation signaled by CD40 and both TNF receptors and inhibits LMP1-mediated NF-kappa-B activation by blocking the association of TRAF2 with LMP1. TRAF2 is necessary for the cellular response to TNF-alpha by connecting upstream signalling molecules to the IKKs and p65.

LIM domain only 1 (LMO1) is a protein-coding gene. LMO1 encodes a transcriptional regulator which contains two cysteine-rich LIM domains but lacks a DNA-binding domain. LIM domains might play a part in protein interactions; hence the protein may regulate transcription by competitively binding to specific DNA-binding transcription factors.

SH3 domain-binding glutamic acid-rich-like protein 2 (SH3BGRL2) belongs to the human SH3BGR family. SH3BGRL2 is a protein of 107 amino acids, which, like SH3BGRL and SH3BGRL3 proteins, is highly homologous to the N-terminal region of the SH3BGR protein and seems to be related to Glutaredoxins and to PKC-interacting cousin of thioredoxin homology domain. SH3BGRL2 is highly expressed in the brain, placenta, liver and kidney and it is also expressed in the retina. The SH3BGRL2 gene is located to chromosome 6q13-15 and its messenger RNA has a large 3' untranslated region containing several AUUUA repeats.

Listeriolysin O (aka LLO) is a hemolysin produced by Listeria monocytogenes bacteria, the pathogen responsible for causing listeriosis. The toxin may be regarded as a virulence factor, since it is crucial for the virulence of L. monocytogenes. LLO is a single polypeptide protein encoded by the hlyA gene and composed of 529 residues. LLO is a thiol-activated cholesterol-dependent pore forming toxin protein; therefore, it is activated by reducing agents and inhibited by oxidizing agents. Still, LLO differs from other thiol-activated toxins, as its cytolytic activity is maximized at a pH of 5.5. Inside the acidic phagosomes (average pH ~ 5.9) of cells that have phagocytosed L. monocytogenes, LLO is selectively activated by maximizing activity at a pH of 5.5. Following the phagosome lysis by LLO, the bacterium breaks out into the cytosol, where it is able to grow intracellularly, and the toxin has reduced activity in the more basic cytosol. Thus, LLO permits L. monocytogenes to break out from the phagosomes into the cytosol without harming the plasma membrane of the infected cell, which allows the bacteria to live intracellularly, where they are sheltered from extracellular immune system factors such as the complement system and antibodies. LLO also brings about dephosphorylation of histone H3 and deacetylation of histone H4 in the early phases of infection, before entry of L. monocytogenes into the host cell. The pore-forming activity is not implicated in causing the histone modifications. The modifications of the histones affect the down regulation of genes encoding proteins involved in the inflammatory response. Therefore, LLO may be significant in subverting the host immune response to L. monocytogenes. At its NH2-terminus it possesses a 25 residues long typical signal sequence excited during the secretion process. Moreover, in its NH2-terminus there is also a 19 amino acids PEST- like sequence that may target this toxin for degradation. The PEST-like sequence found in LLO and is considered crucial for virulence, given that mutants lacking the sequence lysed the host cell. Nevertheless, contrary to PEST's supposed role in protein degradation, evidence implies that the PEST-like sequence may control LLO production in the cytosol rather than increase degradation of LLO.

R-Spondin-1 (Rspo1) is a part of the Rspondin family. Rspo1 plays a role as an activator of the canonical Wnt signaling pathway by acting as a ligand for LGR4-6 receptors. Rspo1 induces the onset of crypt cell proliferation and increases intestinal epithelial healing effect. Rspo1 is negatively regulating the TGF-beta pathway.

Activity-regulated cytoskeleton-associated protein (ARC) takes part in the regulation of cell morphology and cytoskeletal organization and is required for consolidation of synaptic plasticity as well as formation of long-term memory. ARC regulates endocytosis of AMPA receptors in response to synaptic activity and is also required for homeostatic synaptic scaling of AMPA receptors. ARC is required in the stress fiber dynamics and cell migration.

SSR is a glycosylated endoplasmic reticulum (ER) membrane receptor involved in protein translocation across the ER membrane. SSR is formed of 2 subunits, a 34-kD glycoprotein encoded by this gene and a 22-kD glycoprotein. SSR gene creates a number of mRNA species due to complex alternative polyadenylation. SSR is unique since it exploits arrays of polyA signal sequences which are mostly non-canonical.