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The bone morphogenetic protein (BMP) receptors are a family of transmembrane serine/threonine kinases that include the type I receptors BMPR1A and BMPR1B and the type II receptor BMPR2. These receptors are also closely related to the receptors, ACVR1 and ACVR2. The ligands of these receptors are members of the TGF-beta superfamily. TGF-betas transduce their signals through the formation of heteromeric complexes with 2 different types of serine (threonine) kinase receptors: type I receptors of about 50-55 kD and type II receptors of about 70-80 kD. Type II receptors bind ligands in the absence of type I receptors, but they require their respective type I receptors for signaling, whereas type I receptors require their respective type II receptors for ligand binding.

GABARAPL1 [Gamma-aminobutyric acid (GABA) receptor-associated protein-like 1] is a member of the MAP1 LC3 family. GABARAPL1 increases cell surface expression of kappa type opioid receptor through facilitating anterograde intracellular trafficking of the receptor.

POU5F1 is a homeodomain transcription factor of the POU family, expressed in embryonic stem (ES) cells and embryonic carcinoma (EC) cells.POU5F1 is significantly involved in the signaling pathway for maintaining self-renewal and pluripotency of ES cells. POU5F1 has 2 distinct DNA binding domains which independently bind half-sites of the canonical octamer motif. This flexibility allows POU5F1 to bind with distinct DNA motifs by forming heterodimers with other transcription factors or by forming homodimers in several conformations. Human POU5F1 contains a 75aa POU specific (POUS) domain and a 60aa POU-Homeo-(POUH) domain connected by a linker region. The Human POU5F1 specifically interacts with Octamer motif ATGCAAAT. In addition, 2 proline-rich domains in the N-terminal and C-terminal regions are vital for POU5F1 transactivation. POU5F1 regulates a number of target genes and has been shown to work jointly with other transcription factors including Sox2 as well as Nanog to sustain stem cell potency and self-renewal.

Mediator Complex Subunit 27 (MED27) is a subunit of the CRSP (cofactor required for SP1 activation) complex, which, together with TFIID, is necessary for efficient activation by SP1. MED27 is a component of the Mediator complex, a coactivator involved in the regulated transcription of virtually all RNA polymerase II-dependent genes. MED27 protein is also a component of other multisubunit complexes such as the thyroid hormone receptor-(TR-) associated proteins which interact with TR and facilitate TR function on DNA templates in conjunction with initiation factors and cofactors. The activation of MED27 gene transcription is a multistep process, which is triggered by factors that identify transcriptional enhancer sites in DNA.

Chromosome 19 Open Reading Frame 80 (C19ORF80) is a significant new regulator of lipid metabolism which regulates serum triglyceride levels, possibly by promoting ANGPTL3 cleavage. C19ORF80 belongs to the ANGPTL protein family. C19ORF80 is a hormone which specifically promotes pancreatic beta cell proliferation and beta cell mass expansion, thus improving glucose tolerance. C19ORF80 is mainly expressed in the liver; it is also expressed in adipose tissues. C19ORF80 is expressed in response to food intake and stimulated by insulin.

Transcription Factor B2, Mitochondrial (TFB2M) is an S-adenosyl-L-methionine-dependent methyltransferase which specifically dimethylates mitochondrial 12S rRNA at the conserved stem loop. In addition, TFB2M is essential for basal transcription of mitochondrial DNA, most likely via its interaction with POLRMT and TFAM. TFB2M promotes transcription independently of the methyltransferase activity. TFB2M like TFB1M, activates transcription of mitochondrial DNA more effectively, whilst having less methyltransferase activity.

Purine-Rich Element Binding Protein B (PURB) is a single-stranded DNA-binding protein which takes part in the dendritic transport of a subset of mRNAs. PURB operates as repressor in myoblasts and fibroblasts in the control of vascular smooth muscle alpha-actin gene transcription. PURB binds preferentially to the single strand of the purine-rich element termed PUR, which is present at origins of replication and in gene flanking regions in various eukaryotes from yeasts through humans.

CCAAT/enhancer binding protein(C/EBP) g is a family of transcription factors all contain a highly conserved, basic-leucine zipper domain at the C-terminus that is involved in dimerization and DNA binding. C/EBP family of transcription factors regulates viral and cellular CCAAT/enhancer element-mediated transcription. C/EBP family consist of several related proteins, C/EBP a,b,g,d, that form homodimers and/or form heterodimers with each other. C/EBP proteins contain the bZIP region, which is characterized by two motifs in the C-terminal half of the protein; a basic region involved in DNA binding and a leucine zipper motif involved in dimerization. C/EBP g may cooperate with Fos to bind PRE- enhancer elements.

Tripartite Motif Containing 33 (TRIM33) belongs to the tripartite motif family. This motif includes 3 zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. TRIM33 is assumed to be a transcriptional corepressor. TRIM33 functions as an E3 ubiquitin-protein ligase. TRIM33 also promotes SMAD4 ubiquitination, nuclear exclusion and degradation via the ubiquitin proteasome pathway. In addition, TRIM33 inhibits the transcriptional response to TGF-beta/BMP signaling cascade. Furthermore, TRIM33 has a role in the control of cell proliferation.

The GAGA factor is a sequence-specific DNA-binding protein, which participates in the regulation of the expression of a variety of different classes of genes in Drosophila such as many developmentally regulated genes, stress induced genes, and cell cycle regulated genes, as well as housekeeping genes. GAGA contains a C-terminal glutamine-rich domain and a highly conserved N-terminal POZ domain which reported to be involved in self-oligomerization in a number of other POZ domain containing proteins. In case of GAGA protein, the N-terminal POZ domain mediates the formation of oligomers both in vitro and in vivo.

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.

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.

DECR1 is a mitochondrial protein which exists as a homotetramer and is a member of a family of short-chain dehydrogenases/reductases. DECR1 acts as an auxiliary enzyme of beta-oxidation andt partakes in the metabolism of unsaturated fatty enoyl-CoA esters. in particular, DECR1 uses NADP+ to catalyze the reduction of 2,4-dienoyl-CoA to yield trans-3-enoyl-CoA that can subsequently be used as an intermediate in the Krebs cycle. Furthermore, DECR1 is believed to work as a tumor suppressor, possibly downregulating the expression of Neu and slowing the rate of tumorigenesis.

DDIT4 has a role in the regulation of reactive oxygen species. DDIT4 is upregulated at the transcriptional level as a reaction to stress due to DNA damage and glucocorticoid treatment. DDIT4 negatively regulates the mammalian target of Rapamycin, a serine/threonine kinase frequently referred to as mTOR. DDIT4 is vital in the coupling of extra- and intracellular cues to mTOR regulation.

Transcription Factor 4 (TCF4) acts as a transcription factor and takes part in the initiation of neuronal differentiation. TCF4 recognizes an Ephrussi-box ('E-box') binding site ('CANNTG') - a motif primary identified in immunoglobulin enhancers. TCF4 is mainly expressed in pre-B-cells, even though it is present in other tissues as well.

MGAT2 is an enzyme which takes part in the catalyzation of a crucial step in the reaction of oligomannose which converts to complex N-glycans. MGAT2 has three domains, classic to glycosyltransferase: short N-terminal cytoplasmic domain, a C-terminal catalytic domain and hydrophobic non-cleavable signal-anchor domain. The enzyme MGAT2 is encoded by the MGAT2 gene in humans. There are no introns in the DNA coding the gene, therefore mutations in the MGAT2 will result in carbohydrate-deficient glycoprotein syndrome, type II.

REG protein was shown to be stimulated during the regeneration of pancreatic islets. Since then, many Reg-related proteins have been identified in humans and other animals. In human, the four REG family genes, i.e., REG 1 alpha, REG 1 beta, REG-related sequence (RS) and HIP/PAP, have so far been isolated. These Reg-related proteins are classified into four subfamilies according to their amino-acid sequences, but they share a similar structure and physiological function. Reg protein is a growth factor for pancreatic beta cells and also suggests that the administration of Reg protein could be used as another therapeutic approach for diabetes mellitus. Human REG cDNA which encodes a 166-amino acid protein with a 22-amino acid signal peptide. The amino acid sequence of human REG protein has 68% homology to that of rat Reg protein.
Reg I was found to be expressed mainly in pancreatic beta and acinoductular cells as well as gastric fundic enterochromaffin-like (ECL) cells. Reg I production in ECL cells is stimulated by gastrin, as well as by the proinflammatory cytokine, cytokine-induced neutrophil chemoattractant (CINC)-2Beta. In patients with chronic hypergastrinemia, Reg production is stimulated, with the increased proliferation of gastric mucosal cells. Patients with Helicobacter pylori infection also showed increased Reg production in the gastric mucosa, partly via increased plasma gastrin concentration and partly via increased proinflammatory cytokine production. The serum concentration of the reg-protein was significantly higher in patients with various pancreatic diseases than in normal controls, and was also significantly higher in patients with acute pancreatitis or chronic relapsing pancreatitis than in patients with chronic pancreatitis. Furthermore, the serum PSP/reg-protein concentration was also significantly increased in liver cirrhosis, choledocholithiasis, and various cancers of the digestive system.

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).

Protein Phosphatase 1, Regulatory Subunit 8 (PPP1R8) is the RNA-binding subunit of a key species of protein phosphatase-1 in the nucleus. The PPP1R8 enzyme is an inhibitor subunit of the main nuclear protein phosphatase-1 (PP-1). PPP1R8 has RNA-binding activity however it doesn’t cleave RNA and may target PP-1 to RNA-associated substrates. Two isoforms of the PPP1R8 protein are specific inhibitors of type 1 serine/threonine protein phosphatases which can bind but not cleave RNA. The third isoform of the PPP1R8 protein is deficient in of the phosphatase inhibitory activity nonetheless it is a single-strand endoribonuclease comparable to RNase E of E. coli.

ETS homologous factor (EHF) is a part of the ESE subfamily of Ets transcription factors. Ets factors are an important kind of transcriptional regulators which take part in hema-topoiesis, angiogenesis, organogenesis, oncogenesis and specification of neuronal connectivity. EHF is expressed solely in a subset of epithelial cells, with highest expression noticed in glandular epithelium of the prostate, pancreas, salivary gland and trachea. EHF transactivates the c-Met promoter via 3 high affinity binding sites, which support the notion that EHF contribute to branching morphogenesis.

RALY belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) gene family. RALY takes part in pre-mRNA splicing and also in embryonic development. Moreover, alternate splicing results in multiple transcript variants have been found for RALY.

In the absence of additional proteins - the general transcription factors (GTFs) RNA polymerases are unable to initiate RNA synthesis. GTFs accumulate in a complex on the DNA promoter and recruit the RNA polymerase. GTF3C family proteins are vital for RNA polymerase III to produce several small nuclear and cytoplasmic RNAs, including 5S RNA, tRNA, and adenovirus-associated (VA) RNA of both cellular and viral origin.

TNFRSF13B (TACI) is a transmembrane receptor protein found predominantly on the surface of B cells (a significant part of the immune system). TACI was at first discovered owing to its ability to interact with calcium-modulator and cyclophilin ligand (CAML). Later on, it was found that TACI plays a key role in humoral immunity by interacting with two members of the TNF family. Also, TACI controls T cell-independent B cell antibody responses, isotype switching, and B cell homeostasis.