Phosphatase

RNA Guanylyltransferase And 5'-Phosphatase also known as RNGTT is a bifunctional mRNA-capping enzyme which exhibits RNA 5'-triphosphatase activity in the N-terminal section and mRNA guanylyltransferase activity in the C-terminal section. In addition, RNGTT catalyzes the first two steps of cap formation, through removing the gamma-phosphate from the 5'-triphosphate end of nascent mRNA to yield a diphosphate end, and also by transferring the gmp moiety of GTP to the 5'-diphosphate terminus.

Magnesium-dependent phosphatase 1 (MDP1) is a memeber of the HAD-like hydrolase superfamily. MDP1 is a magnesium-dependent phosphatase which may act as a tyrosine phosphatase. MDP1 is inhibited by vanadate and zinc, and slightly by calcium.

Human Phosphoserine phosphatase (hPSP) is an important enzyme in the phosphorylated pathway of serine biosynthesis, which contributes a major portion of the endogenous L-serine. Similar to known L-3-phosphoserine phosphatases, it catalyzed the Mg2+-dependent hydrolysis of L-phosphoserine and an exchange reaction between L-serine and L-phosphoserine. Recently, its complex structures reveal that the open-closed environmental change of the active site, generated -helical bundle domain, is important to substrate by local rearrangement of the recognition and hydrolysis.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) belongs to the HAD-like hydrolase superfamily. LHPP is an exceptional enzyme which hydrolyzes not only oxygen-phosphorus bonds in inorganic pyrophosphate but also nitrogen-phosphorus bonds in phospholysine, phosphohistidine and imidodiphosphate in vitro. LHPP is expressed in the liver, kidney and moderately in the brain.

Protein Phosphatase 4 Catalytic subunit (PPP4C), is a part of the Serine/threonine-protein phosphatase catalytic subunits which tskes part in dephosphorylation and regulation of HDAC3. The protein phosphatase (PP) holoenzyme is a trimeric complex compound of a regulatory subunit, a variable subunit and a catalytic subunit. 4 major families of protein phosphatase catalytic subunits have been identified, designated PP1, PP2A, PP2B (calcineurin) and PP2C.

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.

PPP3R1 is a Ser/Thr-specific calcium and calmodulin-dependent protein phosphatase which takes a vital part in the T cell activation pathway. Calcineurin is composed of two subunits; calcineurin A (CnA) and calcineurin B (CnB). Dephosphorylation of the nuclear factor of activated T-cells (NF-AT) by Calcineurin is essential for NF-AT activation, nuclear translocation, and early gene expression in T-cells.

PPP3CA (aka Calcineurin A) is a major soluble calmodulin binding protein in the brain and a Ca2+/calmodulin dependent serine/threonine protein phosphatase, with a relatively limited substrate specificity. PPP3CA activates the T cells of the immune system and can be blocked by drugs. PPP3CA activates NFATc (a transcription factor) by dephosphorylating it. The activated NFATc is subsequently translocated into the nucleus, where it upregulates the expression of interleukin 2.

Protein Phosphatase 2, Regulatory Subunit A Alpha, also known as PPP2R1A is part of the PPP family of phosphatases, which regulates a diversity of vital cellular processes. PPP2R1A subunit, PR65, functions as a scaffolding molecule which coordinates the assembly of the catalytic subunit and a variable regulatory B subunit. PPP2R1A is essential for proper chromosome segregation as well as for centromeric localization of SGOL1 in mitosis. Furthermore, PPP2R1A phosphorylation is an in vivo mechanism which regulates the PP2A signaling complex as well as increasing the PP2A activity in heart failure.

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.

Protein Phosphatase 1, Regulatory Subunit 2 (PPP1R2) is an inhibitor of protein-phosphatase 1 which forms heterodimer with PP1. PPP1R2 is a part of the protein phosphatase inhibitor 2 family.

PPP1R1A is an inhibitor of protein-phosphatase 1. IPP-1 protein plays important in hormonal control of glycogen metabolism. Hormones that elevate intracellular cAMP elevate IPP-1 activity. PPP1R1A activation caused cAMP to control over proteins that are not directly phosphorylated by PKA following a rise in intracellular calcium, IPP-1 is inactivated by calcineurin (PP2B). Multiple domains in IPP-1 target cellular PP1 complexes. PPP1R1A is a cellular regulator of eIF2 alpha phosphorylation.

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.

PPP1CC is vital for cell division and takes part in the regulation of protein synthesis, muscle contractility and glycogen metabolism. Additionally, PPP1CC has a role in long-term synaptic plasticity and regulation of ionic conductance, and has a significant role in dephosphorylating substrates such as the postsynaptic density-associated Ca2+/calmodulin dependent protein kinase II.

PPP1CC is vital for cell division and takes part in the regulation of protein synthesis, muscle contractility and glycogen metabolism. Additionally, PPP1CC has a role in long-term synaptic plasticity and regulation of ionic conductance, and has a significant role in dephosphorylating substrates such as the postsynaptic density-associated Ca2+/calmodulin dependent protein kinase II.

Serine/Threonine-protein phosphatase PP1-alpha catalytic subunit (PPP1CA) is crucial for cell division, and participates in the regulation of glycogen metabolism, muscle contractility and protein synthesis. The PPP1CA protein may have a significant role in dephosphorylating substrates such as the postsynaptic density-associated Ca2+/calmodulin dependent protein kinase II.

PPM1G is part of the PP2C family of Ser/Thr protein phosphatases which are known to be negative regulators of cell stress response pathways. PPM1G is accountable for the dephosphorylation of Pre-mRNA splicing factors, an important factor for the formation of functional spliceosome. PPM1G regulates cell cycle progression.
PPM1G mediates histone dephosphorylation/exchange in response to DNA damage or checkpoint recovery in higher eukaryotes.
The degradation of p21/WAF1 induced by PPM1G is mediated in a proteasome-dependent manner.
Protein phosphatase 1G regulates assembly and function of the beta-catenin degradation complex.

PPM1G is part of the PP2C family of Ser/Thr protein phosphatases which are known to be negative regulators of cell stress response pathways. PPM1G is accountable for the dephosphorylation of Pre-mRNA splicing factors, an important factor for the formation of functional spliceosome. PPM1G regulates cell cycle progression.
PPM1G mediates histone dephosphorylation/exchange in response to DNA damage or checkpoint recovery in higher eukaryotes.
The degradation of p21/WAF1 induced by PPM1G is mediated in a proteasome-dependent manner.
Protein phosphatase 1G regulates assembly and function of the beta-catenin degradation complex.

Protein Phosphatase 1F (PPM1F) is a part of the PP2C family of Ser/Thr protein phosphatases whose members are known to be negative regulators of cell stress response pathways. PPM1F interacts with Rho guanine nucleotide exchange factors (PIX), and as a result blocks the effects of p21-activated kinase 1 (PAK), a protein kinase mediating biological effects downstream of Rho GTPases. Calcium/calmodulin-dependent protein kinase II gamma (CAMK2G/CAMK-II) is one of the substrates of PPM1F. PPM1F is found to be an apoptosis Promoter.

Protein Phosphatase 1D (PPM1D) belongs to the PP2C family of Ser/Thr protein phosphatases whose members are negative regulators of cell stress response pathways. PPM1D is induced by tumor suppressor protein TP53/p53 in response to multiple environmental stresses. PPM1D is a negative regulator of the activity of p38 MAP kinase through which it reduces the phosphorylation of p53 and suppresses p53-mediated transcription and apoptosis. PPM1D is located in a chromosomal area which enlarges in breast cancer.

Protein Phosphatase 2C alpha is a member of the PP2C family of Ser/Thr protein phosphatases. PP2C family members are known to be negative regulators of cell stress response pathways. This phosphatase dephosphorylates, and negatively regulates the activities of, MAP kinases and MAP kinase kinases. It has been shown to inhibit the activation of p38 and JNK kinase cascades induced by environmental stresses. This phosphatase can also dephosphorylate cyclin-dependent kinases, and thus may be involved in cell cycle control. Overexpression of this phosphatase is reported to activate the expression of the tumor suppressor gene TP53/p53, which leads to G2/M cell cycle arrest and apoptosis. Three alternatively spliced transcript variants encoding two distinct isoforms have been described.
Protein phosphatase 2C(PP2C?) is a Mn2+- or Mg2+-dependent protein serine/threonine phosphatase that is essential for regulating cellular stress response in eukaryotes.

PPA2 shares great imagination with members of the inorganic pyrophosphatase (PPase) family. PPA2 is localized to the mitochondrion and owns the signature sequence necessary for the catalytic activity of PPase. PPases catalyze the hydrolysis of pyrophosphate to inorganic phosphate, which is vital for the phosphate metabolism of cells.

PPA1 is a member of the PPase family. PPA1 catalyzes the conversion of one molecule of pyrophosphate to two phosphate ions. Many biochemical pathways use the hydrolysis of PPi to two phosphate ions to make the reactions permanently irreversible. A prominent illustration of this phenomenon is the inorganic pyrophosphatase catalyzation in the hydrolysis reaction at the beginning of lipid degradation. Inorganic pyrophosphatase provides the motivation for the activation of fatty acids destined for oxidation by stimulating the rapid hydrolysis of pyrophosphate.

Inorganic pyrophosphatase (ppa) is a member of the Ppase family. PPA is an enzyme which catalyzes the conversion of one molecule of pyrophosphate to two phosphate ions. Since this is a highly exergonic reaction, it can therefore be coupled to unfavorable biochemical transformations in order to drive these transformations to completion. The role of the PPA enzyme is a critical one in the lipid metabolism (including lipid synthesis and degradation), calcium absorption and bone formation, DNA synthesis, as well as other biochemical transformations.

Inorganic pyrophosphatase (ppa) is a member of the Ppase family. PPA is an enzyme which catalyzes the conversion of one molecule of pyrophosphate to two phosphate ions. Since this is a highly exergonic reaction, it can therefore be coupled to unfavorable biochemical transformations in order to drive these transformations to completion. The role of the PPA enzyme is a critical one in the lipid metabolism (including lipid synthesis and degradation), calcium absorption and bone formation, DNA synthesis, as well as other biochemical transformations.

ITPA enzyme catalyzes the pyrophosphohydrolysis of both ITP (inosine triphosphate) and dITP (deoxyinosine triphosphate) to IMP (inosine monophosphate) and diphosphate. IMP is exercised as a substrate for purine nucleotide pathways. IMP is phosphorylated to ITP, and ITPA mediates the concentration of ITP in the cell by changing ITP back to IMP. Defects in ITPA result in ITPA deficiency which is thought to be inherited and is characterized by an over-accumulation of ITP in erythocytes, leukocytes and fibroblasts.

PHPT1 is a member of the Janus protein familyand is 125 amino acid long. PHPT1 appears as a monomer in the cytoplasm and is an EDTA-insensitive phosphohistidine phosphatase. Overexpression of PHPT1 resolts in specific phosphohistidine phosphatase activity towards phosphopeptide I, with no activity detected towards phosphotyrosine, phosphothreonine and phosphoserine peptides.

PHPT1 is a member of the Janus protein familyand is 125 amino acid long. PHPT1 appears as a monomer in the cytoplasm and is an EDTA-insensitive phosphohistidine phosphatase. Overexpression of PHPT1 resolts in specific phosphohistidine phosphatase activity towards phosphopeptide I, with no activity detected towards phosphotyrosine, phosphothreonine and phosphoserine peptides.

THTPA enzyme is part of the THTPase family. THTPA is localized to the cytoplasm and expressed at small quantities in a variety of tissues, including testis, uterus, prostate, bladder, lung and kidney. THTPA is a hydrolase that catalyzes the H2O-dependent hydrolysis of thiamine triphosphate (THTP) to thiamine diphosphate (THDP), the main form of thiamine within the cell. THTPA occurs as a monomer and is activated at an optimal pH of 8.5.

Pyridoxal phosphate phosphatase PHOSPHO2, orphan 2 (PHOSPHO2) is a member of the haloacid dehalogenase (HAD) superfamily. Phosphatase has an elevated activity toward phosphoethanolamine (PEA) and phosphocholine (PCho). PHOSPHO 1, a phosphoethanolamine/phosphocholine phosphatase, is upregulated in mineralizing cells and is believed to be implicated in the production of inorganic phosphate for bone mineralization. PHOSPHO2 is a recognized phosphatase sharing a 42% sequence identity with PHOSPHO1. PHOSPHO1 and PHOSPHO2 are especially similar, however surprisingly recombinant PHOSPHO2 hydrolyses phosphoethanolamine and phosphocholine comparatively inadequately.

PHOSPHO1 is involved in mineralization process & plays a role in bone and cartilage matrix mineralization.
PHOSPHO1 is expressed at sites of mineralization in bone and cartilage. Highly expressed in osteoblast cell line SaOS-2 which produces a mineralized matrix.
Orphan-1 is collagen type -2 is specific for cartilaginous tissues. Orphan1 is essential for the normal embryonic development of the skeleton, for linear growth and for the ability of cartilage to resist compressive forces.
Phosphoethanolamine (2-O3POCH2CH2NH3) is a key intermediate in the formation of cephalins, it is formed in liver and brain by phosphorylation of ethanolamine.
PHOSPHO2 and PHOSPHO1 suggest subtle differences in the charge distributions around the putative substrate entry site and in the location of potential H-bond donors.
PHOSPHO1 exhibits high specific phosphoethanolamine and phosphocholine phosphatase activities PHOSPHO1 is a phosphatase enzyme for which expression is upregulated in mineralizing cells. PHOSPHO1 has been implicated in the generation of Pi for matrix mineralization, a process central to skeletal development. PHOSPHO1 is a member of the haloacid dehalogenase (HAD) superfamily of Mg2+-dependent hydrolases. PHOSPHO1 exhibits high specific activities toward phosphoethanolamine (PEA) and phosphocholine (PCho).

Phosphoglycolate phosphatase (PGP) is discovered in all tissues including red cells, lymphocytes and cultured fibroblasts (at protein level). PGP is most active in skeletal muscle and cardiac muscle. The catalytic activity of PGP is 2-phosphoglycolate + H2O = glycolate + phosphate. Diseases associated with PGP include tardive dyskinesia and polycystic kidney disease.

Phosphoglycolate phosphatase (PGP) is discovered in all tissues including red cells, lymphocytes and cultured fibroblasts (at protein level). PGP is most active in skeletal muscle and cardiac muscle. The catalytic activity of PGP is 2-phosphoglycolate + H2O = glycolate + phosphate. Diseases associated with PGP include tardive dyskinesia and polycystic kidney disease.

IMPA2 is a member of the inositol monophosphatase family. IMPA2 catalyzes the dephosphoylration of inositol monophosphate and has a significant role in phosphatidylinositol signaling. IMPA2 can use the myo-inositol monophosphates, scylloinositol 1,4-diphosphate, glucose-1-phosphate, beta-glycerophosphate, and 2'-AMP as substrates. IMPA2 is a pharmacological target for lithium Li(+) action in brain. IMPA2 is considered to have a role in schizophrenia and bipolar disorder.

Inositol monophosphatase1 (IMPA1) is responsible for the provision of inositol essential for synthesis of phosphatidylinositol and polyphosphoinositides. IMPA1 has a central role in the phosphatidylinositol signaling pathway by catalyzing the hydrolysis of inositol monophosphates. IMPA1 has been recognized as the pharmacological target for lithium action in the brain. The IMPA1 enzyme has a magnesium-dependent phosphatase activity and is inhibited by therapeutic concentrations of lithium. Inhibition of inositol monophosphate hydroylosis and ensuing depletion of inositol for phosphatidylinositol synthesis may perhaps explain the anti-manic and anti-depressive effects of lithium administered to treat bipolar disorder.

PDXP is the active form of vitamin B6 that functions as a coenzyme in preserving biochemical homeostasis. The desired degradation route from PLP to 4-pyridoxic acid involves the dephosphorylation of PLP by PDXP. PDXP shows activity to pyridoxal 5''-phosphate (PLP), pyridoxine 5''-phosphate (PMP) and Pyridoxine 5''-phosphate (PNP), with a highest activity with PLP followed by PNP.

Fructose-1,6-bisphosphatase isozyme 2 (FBP2) is a part of the FBPase class 1 family. FBP2 is a gluconeogenesis regulatory enzyme Which catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and inorganic phosphate.

FBP1 or Fructose-1, 6-bisphosphatase 1 is an enzyme, catalyzing the formation of fructose 6-phosphate & inorganic phosphate from fructose 1, 6-bisphosphate. FBP1 is part of the gluconeogenesis regulatory enzymes. Mutations in the enzyme gene can result in metabolic acidosis & hypoglycemia.

FBP1 is a gluconeogenesis regulatory protein which catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and inorganic phosphate. FBP1 deficiency is associated with hypoglycemia and metabolic acidosis. FBP1 regulates mouse endogenous glucose production. FBP1 coupled with phosphofructokinase (PFK) takes part in the metabolism of pancreatic islet cells.

Prostatic acid phosphatase, also known as PAP, is an enzyme produced by the prostate. PAP may be found in increased amounts in men with prostate cancer.
PAP’s physiological function may be associated with the liquefaction process of semen.
The highest levels of PAP are found in metastasized prostate cancer. Diseases of the bone, such as Paget's disease or hyperparathyroidism, diseases of blood cells (sickle-cell disease) or multiple myeloma or lysosomal storage diseases (Gaucher's disease), will show moderately higher levels.
Certain medications can cause temporary changes in PAP levels. Manipulation of the prostate gland through rectal exam, biopsy or massage may increase the level.

SSU72 is an extremely conserved homologue of yeast Ssu72, a CTD phosphatase and a component of the polyadenylation/termination machinery. SSU72 interacts with TFIIB, Rb and DNAM-1 and operates to catalyze the dephosphorylation of target proteins, and taking part in RNA processing and termination via dephosphorylation of Pol II. SSU72 is found in multiple alternatively spliced isoforms.

Ectonucleotide Pyrophosphatase-2, aka ENPP2, a part of the ectonucleotide pyrophosphatasefamily. ENPP2 is able to cut the phosphodiester bond between the alpha and the beta position of triphosphate nucleotides, acting as an ectonucleotide phosphodiesterase producing pyrophosphate, as most members of the ENPP family. It is unlike ENPP-1 and ENPP-3, has weak activity against nucleotides, but shows a lysophospholipase D activity which allows the formation of LPA and choline from lysophosphatidylcholine. As well, ENPP-2 and LPA are involved in several inflammatory-driven diseases such as arthritis and asthma.

Ectonucleotide Pyrophosphatase (ENPP1) belongs to the ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP) family. ENPP1 is a type II transmembrane glycoprotein comprised of 2 identical disulfide-bonded subunits. The ENPP1 protein has broad specificity and cleaves various substrates, including phosphodiester bonds of nucleotides and nucleotide sugars and pyrophosphate bonds of nucleotides and nucleotide sugars. The ENPP1 protein can hydrolyze nucleoside 5' triphosphates to their corresponding monophosphates and it may also hydrolyze diadenosine polyphosphates. ENPP1 gene mutations are linked with 'idiopathic' infantile arterial calcification and ossification of the posterior longitudinal ligament of the spine (OPLL).

Enolase-phosphatase E1 (ENOPH1) belongs to the MasA family of the HAD (halo-acid dehalogenase)-like hydrolase superfamily. ENOPH1 is a bifunctional enzyme which demonstrates both phosphatase and atypical enolase activities. ENOPH1 has a significant role in the ubiquitous methionine salvage pathway which is a biochemical pathway found in all organisms that regulate methionine levels in the cell.

Deoxyuridine Triphosphatase (DUT) is a ubiquitous enzyme that functions in nucleotide metabolism. Deoxyuridine Triphosphatase, in the presence of magnesium ions, is responsible for hydrolyzing dUTP to dUMP and diphosphate. This reaction is imperative for keeping the intracellular dUTP concentration low so that uracil does not become incorporated into DNA. Extensive integration of uracil into DNA can eventually lead to cell death. This suggests that DUT is crucial for cell viability, further implying that it is a prospective target for anticancer therapy.

Dual Specificity Phosphatase 6, also known as DUSP6 belongs to the dual specificity protein phosphatase subfamily. DUSP6 is a Protein coding gene which inactivates MAP kinases. Various members of the family of dual specificity phosphatases show diverse tissue distribution, subcellular localization, and different modes of inducibility of their expression by extracellular stimuli.

DUSP3 belongs to the dual specificity protein phosphatase subfamily which inactivates their target kinases by dephosphorylating both the phosphoserine/threonine and phosphotyrosine residues. DUSP3 negatively regulate members of the mitogen-activated protein kinase superfamily that are related to cellular proliferation and differentiation. DUSP3 is expressed in both breast and ovarian tissues and displays activity both for tyrosine-protein phosphate and serine-protein phosphate, but exhibits a strong preference toward phosphotyrosines, specifically dephosphorylates and inactivates ERK1 and ERK2.

Dual Specificity Phosphatase 26 (DUSP26) inhibits MAP kinase p38 by dephosphorylating it and inhibits p38-mediated apoptosis in anaplastic thyroid cancer cells. DUSP26 also induces activation of MAP kinase p38 and c-Jun N-terminal kinase. DUSP26 inactivates MAPK1 and MAPK3 which leads to dephosphorylation of heat shock factor protein 4 and a decrease in its DNA-binding activity.