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The 26S proteasome is a multicatalytic proteinase complex with a well ordered structure composed of two complexes- a 20S core and a 19S regulator. PSMD11 is a non-ATPase subunit of the 19S regulator. The 20S core is composed of four rings of 28 non-identical subunits; two rings are composed of 7 alpha subunits and two rings are composed of 7 beta subunits. The 19S regulator is composed of a base that contains six ATPase subunits and two non-ATPase subunits, and a lid that contains up to ten non-ATPase subunits. Proteasomes are spread throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An indispensable function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides.

SARS Membrane protein is a membranal protein which plays a crucial role in the virus’ life cycle. This protein has 3 outer cell structural antigens, the envelope (E), membrane (M)and spike (S) antigens. SARS Membrane protein is essential to the process of assembly, budding, creation of the envelope and pathogenesis.

PAPSS1 is a bifunctional enzyme with APS kinase and ATP sulfurylase activity. PAPSS1 facilitates two stages in the sulfate activation pathway, yielding 3'-phosphoadenylylsulfate (PAPS). Additionally, PAPSS1 takes part in the biosynthesis of sulfated L-selectin ligands in endothelial cells.

Prostatic Acid Phosphatase or ACPP is part of a family of proteins called histidine acid phosphatase. ACPP enhances the hydrolyzation of many phosphate monoesters and proteins that are phosphorylated. In order to function best, ACPP needs a range of range of 4-6 pH, furthermore, L(+)-tartrate inhibits ACPP’s catalyzation. This enzyme can act as a lipid phosphatase as well and can inhibit lysophosphatidic acid in seminal plasma.

SKP1 is a F-box enzyme which functions as a substrate recognition component of the SCF ubiquitin ligase complex which controls the ubiquitination of proteins involved in cell cycle progression, signal transduction and transcription. SKP1 binds to proteins containing an F-box motif, such as cyclin F, S-phase kinase-associated protein 2, and other regulatory proteins involved in ubiquitin dependent proteolysis. SKP1 takes part in the control of beta-catenin levels and the activity of beta-catenin dependent TCF transcription factors. SKP1 serves as an adapter that links the F-box protein to CUL1 in the SCF complex.

The protein kinase A holoenzyme is a heterotetramer composed of two types of subunits: Catalytic and Regulatory. The Catalyticsubunit contains the enzyme's active site. It also contains a domain that binds ATP and a domain that binds the regulatory subunit. The Regulatory subunit consists oftwo molecules which bind one another in an anti-parallel orientation to form a homodimer; for type I subunits- this binding is covalent via disulfide bonds. This subunit also has has two domains that bind cyclic AMP, a domain that interacts with a catalytic subunit, and an "auto-inhibitory" domain that serves as a substrate or pseudosubstrate for the catalytic subunit. Regulatory subunits may also have biologic activity distinct from their role in modulating catalytic subunit activity. Regulatory subunits exist in two major forms, RI and RII, with each form having two subtypes designated alpha and beta. Each of the four isotypes of the regulatory subunit is encoded by a different gene. In addition, three isotypes of the catalytic subunit have been identified (alpha, beta and gamma). The different isotypes tend to have different distributions within cells and among tissues. Type I enzymes inhabit cytoplasmic, soluble fractions of the cell, whereas type II enzymes tend to associate with cellular membranes.

PGLS is an enzyme in the second step pentose phosphate pathway. 6-Phosphogluconolactonase is crucial for the synthesis of nucleotide sugars and NADPH, the key cause for decreasing power. PGLS transforms 6-phosphogluconolactone to 6-phosphogluconate.

Hydroxymethylglutaryl-CoA lyase (HMGCL) is a mitochondrial matrix protein which is a member of the HMG-CoA lyase family. HMGCL is a homodimer and participates in leucine catabolism and ketogenesis, the hepatic synthesis of ketone bodies which, during fasting, provides a major source of energy for the heart, brain and kidney. More precisely, HMGCL catalyzes the final step of these processes, the cleavage of 3-hydroxy-3-methylglutaryl-CoA to acetoacetic acid and acetyl-CoA.

MARCKS-related protein (MARCKSL1) which is a part of MARCKS family of PKC substrate is broadly used in the signal transduction studies as an indicator of PKC activation. MARCKSL1 plays a part in the coordination of membrane-cytoskeletal signaling events, including secretion, migration, phagocytosis and cell adhesion and is expressed in a variety of tissues with highest levels found in testis and uterus. Furthermore, MARCKSL1 serves as a regulator of Integrin activation and is thought to regulate Integrin-dependent signal transduction pathways, particularly those involved in macrophage spreading.

ARPC5 is a 151 amino acid subunit of the Arp2/3 complex. ARPC5 is believed to have a role in maintaining the integrity of Arp2/3. ARPC5 is a substrate for MAPKAPK-2 which, via phosphorylation of ARPC5, may participate in Arp2/3 regulatory functions and remodeling of the Actin cytoskeleton.

Proteasome 26S Subunit, Non-ATPase 13 (PSMD13) is a part of the proteasome subunit S11 family and contains one PCI domain. PSMD13 plays a role as a regulatory subunit of the 26S proteasome which takes part in the ATP-dependent degradation of ubiquitinated proteins.

Farnesyl-Diphosphate Farnesyltransferase 1, also known as FDFT1 is a membrane-associated enzyme sited at a branch point in the mevalonate pathway. FDFT1belongs to the phytoene/squalene synthase family. FDFT1 is the 1st specific enzyme in cholesterol biosynthesis, which catalyzes the dimerization of 2 molecules of farnesyl diphosphate in a two-step reaction to form squalene.

PI3Ka plays a specific role in apoptosis in human colon cancer cells. Injection of neutralizing antibodies specific to PI3Ka into adenocarcinoma cells induced apoptosis, a response that was reverted by treating cells with caspase inhibitor. It was also shown that PI3Ka mediated phosphorylation of the p85a adapter reduces the lipid kinase activity of the heterodimer and this gives hints for PI3K-dependent signaling events not requiring production of 3’-phosphorylated phosphoinositides.
PI3Ka is a key regulator of the initiation of keratinocyte differentiation. A decrease in PI3Ka activity results in a loss of keratinocyte adhesion to the extracellular membrane and the initiation of early phase differentiation.

Acid Phosphatase-5, also known as ACP5 is a member of the Purple acid phosphatase family. ACP5 is implicated in osteopontin as well as bone sialoprotein dephosphorylation. ACP5 expression appears to increase in certain pathological states for instance Gaucher & Hodgkin diseases, the hairy cell, the B-cell, as well as the T-cell leukemias.

TIE-1 (tyrosine kinase with Ig and EGF homology domains 1) and TIE-2/Tek comprise a receptor tyrosine kinase (RTK) subfamily with unique structural characteristics: two immunoglobulin-like domains flanking three epidermal growth factor (EGF)-like domains and followed by three fibronectin type III-like repeats in the extracellular region and a split tyrosine kinase domain in the cytoplasmic region. These receptors are expressed primarily on endothelial and hematopoietic progenitor cells and play critical roles in angiogenesis, vasculogenesis and hematopoiesis. Human TIE-1 cDNA encodes a 1122 amino acid (aa) residue precursor protein with an 18 residue putative signal peptide, a 726 residue extracellular domain and a 353 residue cytoplasmic domain. Two ligands, angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2), which bind TIE-2 with high-affinity have been identified. Ang2 has been reported to act as an antagonist for Ang1. Mice engineered to overexpress Ang2 or to lack Ang1 or Tie-1 display similar angiogenic defects.

Phospholipase A1 Member A (PLA1A) is a phospholipase which hydrolyzes fatty acids at the sn-1 position of phosphatidylserine and 1-acyl-2-lysophosphatidylserine. The secreted PLA1A protein hydrolyzes phosphatidylserine in liposomes. PLA1A hydrolyzes phosphatidylserine (PS) in the form of liposomes and 1-acyl-2 lysophosphatidylserine (lyso-PS), but not triolein, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA) or phosphatidylinositol (PI). PLA1A isoform 2 hydrolyzes lyso-PS but not PS. The hydrolysis of lyso-PS in peritoneal mast cells activated by receptors for IgE leads to stimulation of histamine production.

PSME2 is an IFN-gamma inducible proteasome activator essential for production of several key histocompatibility (MHC) class I antigens. Downregulation of PSME2 causes unusual proteasome activation and is connected to the development of intimal hyperplasia (IH) in animal models.

PTGES3 takes part as a cochaperone and is involved in signal transduction.
PTGES3 is a molecular chaperone that localizes to genomic response elements in a hormone-dependent manner and disrupts receptor-mediated transcriptional activation, by promoting disassembly of transcriptional regulatory complexess. PTGES3 is necessary for appropriate functioning of the glucocorticoid and other steroid receptors.
PTGES3 localizes to genomic response elements in a hormone-dependent method and disrupts receptor-mediated transcriptional activation, by promoting disassembly of transcriptional regulatory complexes.

FABP6 also called ileal fatty acid binding protein, is part of the small family of highly conserved, cytoplasmic proteins that bind long-chain fatty acids and other hydrophobic ligands. FABP6 cytosolic protein binds bile acid. FABP6 plays a role in fatty acid uptake, transport, and metabolism. FABP6 stimulates gastric acid and pepsinogen secretion. Seems to be able to bind to bile salts and bilirubins. FABP6 expression is restricted in the small intestine to the ileum where it is involved in the enterohepatic circulation of bile acids. Alternate transcription promoters generate 2 transcript variants, encoding a 128 aa and a 177 aa residue protein. Human FABP6 isoform 2 contains 128 amino acid residues and is acetylated on Ala2. FABP6 binds together fatty acids and bile acids and is directly involved in fatty acid transport and metabolism.

Matrix metalloproteinases are a family of zinc and calcium-dependent endopeptidases that break down extracellular matrix proteins. The MMP9 is secreted as a 92kDa zymogen. Cleavage of ProMMP-9 results in the active enzyme, having a molecular weight of approximately 82kDa. MMP9 is composed of the following domains: a gelatin-binding domain consisting of three fibronectin type II units, a catalytic domain containing the zinc-binding site, a proline-rich type V collagen-homologous domain and a hemopexin-like domain. MMP9 is produced by the several cell types: monocytes, macrophages, neutrophils, keratinocytes, fibroblasts, osteoclasts and endothelial cells. MMP9 is involved in inflammatory responses, tissue remodeling, wound healing, tumor growth and metastasis. MMP9 may also play an important part in local proteolysis of the extracellular matrix and in leukocyte migration, as well as in bone osteoclastic resorption. MMP9 cleaves type IV and type V collagens into large C-terminal three qu

Peroxisome proliferators are non-genotoxic carcinogens which are purported to exert their effect on cells through their interaction with members of the nuclear hormone receptor family termed peroxisome proliferators activated receptors (PPARs). Nuclear hormone receptors are ligand-dependent intracellular proteins that stimulate transcription of specific genes by binding to specific DNA sequences following activation by the appropriate ligand. Studies indicate that PPARs are activated by peroxisome proliferators such as clofibric acid, nafenopin, and WY-14,643, as well as by some fatty acids.

MGLL is a membrane-associated member of the serine hydrolase superfamily. MGLL is expressed in abundance in skeletal muscle and adipose tissue. MGLL functions jointly with hormone-sensitive lipase (LIPE) to hydrolyze intracellular triglyceride stores in adipocytes and other cells to fatty acids and glycerol. MGLL may also complement lipoprotein lipase (LPL) in completing hydrolysis of monoglycerides resulting from degradation of lipoprotein triglycerides.

The recombinant Protein A/G is a genetically engineered protein comprised of 7 IgG-binding domains EDABC-C1C3, corresponding to the Protein A and G domains which are included in the recombinant sequence. The Protein A part is from Staphylococcus aureus segments E, D, A, B and C. The Protein G part is from Streptococcus segments C1 and C3. The recombinant Protein A/G has a broader binding capacity than either Protein A or Protein G alone. The recombinant Protein A/G is ideal for purification of monoclonal or polyclonal IgG antibodies. Protein A/G binds to various human, mouse and rat IgG subclasses such as the human IgG1, IgG2, IgG3, IgG4; mouse IgG2a, IgG2b, IgG3 and rat IgG2a, IgG2c. In addition, Protein A/G binds to total IgG from cow, goat, sheep, horse, rabbit, guinea pig, pig, dog and cat.