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CMV is part of the Betaherpesvirinae subfamily of Herpesviridae; including herpes simplex virustypes 1 and 2, varicella-zoster virus, and Epstein-Barrvirus. The herpesviruses has the common ability to stay latentover long periods of time. CMV has the largest genome of the herpes viruses, ranging from 230-240 kilobase pairs. CMV is a double-stranded linear DNA virus with 162 hexagonal protein capsomeres surrounded by a lipid membrane. Human CMV is composed of unique and inverted repeats that include the existence of 4 genome isomers caused by inversion of L-S genome components (class E). Replication may be divided into immediate early, delayed early, and late gene expression based on time of synthesis after infection. The DNA is replicated by rolling circles. In vitro, CMV replicates in human fibroblasts.

A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

The B19 virus, usually referred to as parvovirus B19 or sometimes as erythrovirus B19, belongs to the family of parvoviruses, genus erythrovirus. B19 virus causes a childhood rash named “fifth disease” or “erythema infectiosum” which is ordinarily known as “slapped cheek syndrome”. Erythroviruses are members of the Parvoviridae family of small DNA viruses. The B19 virus is a non-enveloped, icosahedral virus which contains a single-stranded linear DNA genome. Parvovirus B19 is classified as erythrovirus because of its capability to invade red blood cell precursors in the bone marrow. This virus is mainly spread by infected respiratory droplets; though, blood-borne transmission has also been reported.

Fetuin is a liver-produced negative acute phase protein composed of two subunits, the A and B chains.
Fetuin homologs have been identified in several species including rat, sheep, pig, rabbit, guinea pig, cattle, mouse and human. Multiple physiological roles for these homologs have been suggested, including ability to bind to hydroxyapatite crystals and to specifically inhibit the tyrosine kinase (TK) activity of the receptor (IR).
Fetuin-A (alpha2-Heremans-Schmid glycoprotein; AHSG) is an important circulating inhibitor of calcification in vivo, and is downregulated during the acute-phase response.
Sera from patients on long-term dialysis with low AHSG concentrations showed impaired ex-vivo capacity to inhibit CaxPO4 precipitation.
Fetuin may influence the resolution of inflammation by modulating the phagocytosis of apoptotic cells by macrophages.
ASHG blocks TGF-beta-dependent signaling in osteoblastic cells, and mice lacking ASHG display growth plate defects, increased bone formation with age, and enhanced cytokine-dependent osteogenesis.

SOX2 is a transcription factor that forms a trimeric complex with OCT4 on DNA and controls the expression of a number of genes involved in embryonic development such as YES1, FGF4, UTF1 and ZFP206. SOX4 is important for early embryogenesis and for embryonic stem cell pluripotency.

MRG-binding protein (MRGBP or C20ORF20) is a 204 amino acid protein which is a part of the NuA4 histone acetyltransferase (HAT) complex that functions to acetylate histone H2A and H4. The HAT complex may be essential for the activation of transcriptional programs linked with oncogene and proto-oncogene mediated growth induction, tumor suppressor mediated growth arrest and replicative senescence, apoptosis, and DNA repair. C20ORF20 also has a potential to interact with MORF4L1/MRG15 and MORF4L2/MRGX.

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.

Protein Interacting with PRKCA 1, also known as PICK1 includes a PDZ domain, through which it interacts with protein kinase C, alpha (PRKCA). PICK1 performs as an adaptor which binds to and arranges the subcellular localization of various membrane proteins. PICK1 interacts with multiple glutamate receptor subtypes, monoamine plasma membrane transporters, in addition to non-voltage gated sodium channels, and might target PRKCA to these membrane proteins and therefore regulates their distribution as well as function. PICK1 has also been found to perform as an anchoring protein which particularly targets PRKCA to mitochondria in a ligand-specific manner.

PPIH is a part of the peptidyl-prolyl cis-trans isomerase (PPIase) family. PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and increase protein folding. PPIH enzyme is a precise factor of the complex that comprises pre-mRNA processing factors PRPF3, PRPF4, and PRPF18, as well as U4/U5/U6 tri-snRNP. PPIH possess PPIase activity and acts as a protein chaperone that mediates the interactions between different proteins inside the spliceosome.

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.

PPP3R2 is a calcium-dependent, calmodulin stimulated serine/threonine protein phosphatase. In eukaryotes, the phosphorylation and dephosphorylation of proteins on serine and threonine residues is a crucial means of regulating a wide range of cellular functions including division, homeostasis and apoptosis. Ordinarily the protein phosphatase (PP) holoenzyme is a trimeric complex composed of a regulatory subunit, a variable subunit and a catalytic subunit.

Transmembrane protein PRRT2 holds a proline-rich domain in its N-terminal half. PRRT2 is known to be primarily expressed in brain and spinal cord in embryonic and postnatal stages. Alterations in this gene are the cause for paroxysmal kinesigenic dyskinesia. PRRT2 mutations were found in nearly 30% of sporadic PKC patients.

lysozyme G-like 2 and LYGH (LYG2), is a member of the glycosyl hydrolase 23 family. Lysozyme takes part in human innate immunity by causing bacterial cell lysis. LYG2 contains a SLT domain, a protein domain present in bacterial lytic transglycosylase (SLT) and in eukaryotic lysozymes (GEWL). SLT domain catalyzes the cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid (MurNAc) and N-acetyglucosamine (GlcNAc).

DERP1 is a thiol protease, with a preference for substrates with a large hydrophobic side chain in the P2 position, or with basic residues. DERP1 is a C1 peptidase family member. DERP1 has extensive endopeptidase specificity. DERP1 is N-glycosylated. N-glycanase treatment does not completely remove carbohydrates, suggesting that the protein contains additional glycosylation sites. DERP1 causes an allergic reaction in humans. Common symptoms of mite allergy are bronchial asthma, allergic rhinitis and conjunctivitis. DERP1 binds to IgE in 80% of patients with house dust allergy.

PEST proteolytic signal containing nuclear protein (PCNP) is a nuclear protein involved in cell cycle regulation and tumorigenesis. The PCNP protein is ubiquitinated post-translationally by NIRF (an ubiquitin ligase). The PCNP exists as 3 isoforms produced by alternative splicing events.

PDK1 takes part in the regulation of enzymatic activity of mammalian pyruvate dehydrogenase which is part of a mitochondrial multienzyme complex to catalyze the oxidative decarboxylation of pyruvate and is one of the major enzymes responsible for the regulation of homeostasis of carbohydrate fuels in mammals. PDK1 inhibits glioblastoma growth. PDK1 inhibits the mitochondrial pyruvate dehydrogenase complex by phosphorylation of the e1 alpha subunit, therefore contributing to the regulation of glucose metabolism. PDK1 kinase activity is negatively regulated by binding to 14-3-3.

ISG15 ubiquitin-like Modifier is conjugated to the intracellular target proteins after IFN-alpha or IFN-beta stimulation. ISG15 enzymatic pathway is partially distinct from that of ubiquitin, differing in substrate specificity and interaction with ligating enzymes. ISG15 conjugation pathway uses a dedicated E1 enzyme, but seems to converge with the ub conjugation pathway at the level of a specific E2 enzyme. ISG15 protein targets include STAT1, SERPINA 3G/SPI2A, JAK1, MAPK3/ERK1, PLCG1, EIF2AK2/PKR, MX1/MXA, and RIG-1. Deconjugated by USP18/UBP43 shows specific chemotactic activity towards neutrophils and activates them to induce release of eosinophil chemotactic factors. ISG15 serves as a trans-acting binding factor directing the association of ligated target proteins to intermediate filaments. ISG15 plays a role in autocrine, paracrine and endocrine mechanisms, as in cell-to-cell signaling, possibly partly by inducing ifn-gamma secretion by monocytes and macrophages. ISG15 displays antiviral activity during viral infections. ISG15 in response to IFN-TAU secreted by the conceptus, ligates to and regulate proteins involved in the release of prostaglandin F2-alpha and thus prevent lysis of the corpus luteum and maintain the pregnancy. ISG15 shares several common properties with other ubiquitin-like molecules, but its activity is strongly regulated by precise signaling pathways that have a role in innate immunity.

Pirin (PIR) which belongs to the cupin superfamily, is an Fe(II)-containing nuclear protein expressed in all tissues of the body and concentrated within dot-like subnuclear structures. Pirin may function as a transcriptional cofactor and is involved in the regulation of DNA transcription and replication, as a result of interactions with nuclear factor I/CCAAT box transcription factor as well as B cell lymphoma 3-encoded oncoprotein.

Pleiotrophin (Osteoblast-Specific Factor-1, OSF-1) contains 136 amino acid residues. The sequence is very rich in cationic amino acids (24% of the residues); lysine cluster sequences are found in the N-terminal and C-terminal ends of the structure.
The OSF-1 gene was shown by Northern blotting analysis to be expressed in mouse calvarial osteoblast-enriched cells and in mouse brain tissues, but not in thymus, spleen, kidney, liver, lung, testis or heart. Pleiotrophin has the ability to promote adhesion, migration, expansion, and differentiation of human osteoprogenitor cells. In addition to certain types of cancer, the embryonic growth and differentiation factor pleiotrophin is found also in adults in inflammatory diseases. In osteoarthritis, pleiotrophin is especially expressed in early stages, and its concentrations in the synovial fluid could serve as a marker for the progress of the disease. Pleitrophin might be involved in cartilage repair in osteoarthritis, in particular, in earlier stages.

Polymerase (RNA) III (DNA directed) Polypeptide H(POLR3H) is a member of the eukaryotic RPB7/RPC8 RNA polymerase subunit family. POLR3H is DNA-dependent RNA polymerase which catalyzes the transcription of DNA into RNA utilizing the 4 ribonucleoside triphosphates as substrates. POLR3H has a central role in sensing and curbing infection by intracellular bacteria and DNA viruses. POLR3H functions as nuclear and cytosolic DNA sensor which is involved in innate immune response.

PPP1R14A is a phosphorylation-dependent inhibitor of smooth muscle myosin phosphatase. Inhibition of PPP1R14A results to increased myosin phosphorylation and enhances smooth muscle contraction in the absence of increased intracellular Ca(2+) concentration. Myosin phosphatase can reverse MYL (myosin light chain) phosphorylation to induce a state of relaxation. However, during agonist-induced contraction at constant Ca2+ concurrent inhibition of myosin phosphatase leads to increases in MYL phosphorylation and tension. These calcium-independent increases in myosin phosphorylation and tension are termed calcium sensitization.
Human pregnancy is characterized by the increases of PKN1 expression and CPI-17 phosphorylation in the myometrium. PPP1R14A is mapped to chromosome 19q13.13-q13.2.
PPP1R14A binds directly to protein kinase C and casein kinase I.
PPP1R14A siRNA decreased the level of merlin phosphorylation and consequently Ras and ERK activity in human tumor cell lines.
PKC/CPI-17 mediated pathway in histamine, triggeres cytoskeletal rearrangements causing lung microvascular barrier compromise.