Phosphoprotein phosphatase
Encyclopedia
Phosphoprotein phosphatase is an enzyme
that dephosphorylates certain phosphorylated proteins.
In some contexts, "Phosphoprotein phosphatase" is equated with serine/threonine specific protein phosphatase, and classified under .
In other contexts, the term also includes protein tyrosine phosphatase
and dual-specificity phosphatase
. This latter convention is used in this article.
ions to serine
, threonine
and tyrosine
residues in the enzyme. This addition is catalysed by protein kinase
s. The reverse reaction is carried out by phosphatase.
in the blood
. The enzyme then acts to dephosphorylate other enzymes, such as phosphorylase kinase
, glycogen phosphorylase
, and glycogen synthase
.
This leads to phosphorylase kinase and glycogen phosphorylase's becoming inactive, while glycogen synthase is activated. As a result, glycogen
synthesis is increased and glycogenolysis
is decreased, and the net effect is for energy to enter and be stored inside the cell.
to the enzyme, the energy for which comes from hydrolysing ATP into ADP
or AMP
.
However, dephosphorylation releases phosphates into solution as free ions, because attaching them back to ATP would require energy input.
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
that dephosphorylates certain phosphorylated proteins.
In some contexts, "Phosphoprotein phosphatase" is equated with serine/threonine specific protein phosphatase, and classified under .
In other contexts, the term also includes protein tyrosine phosphatase
Protein tyrosine phosphatase
Protein tyrosine phosphatases are a group of enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins. Protein tyrosine phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular...
and dual-specificity phosphatase
Dual-specificity phosphatase
Dual-specificity phosphatase is a form of phosphatase that can act upon tyrosine or serine/threonine residues.-References:...
. This latter convention is used in this article.
Overview of control of enzyme activity
The control of enzyme activity involves covalent modifications, including the addition of phosphatePhosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
ions to serine
Serine
Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...
, threonine
Threonine
Threonine is an α-amino acid with the chemical formula HO2CCHCHCH3. Its codons are ACU, ACA, ACC, and ACG. This essential amino acid is classified as polar...
and tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...
residues in the enzyme. This addition is catalysed by protein kinase
Protein kinase
A protein kinase is a kinase enzyme that modifies other proteins by chemically adding phosphate groups to them . Phosphorylation usually results in a functional change of the target protein by changing enzyme activity, cellular location, or association with other proteins...
s. The reverse reaction is carried out by phosphatase.
Effects of activation of phosphoprotein phosphatase
Phosphoprotein phosphatase is activated by the hormone insulin, which indicates that there is a high concentration of glucoseGlucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
in the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
. The enzyme then acts to dephosphorylate other enzymes, such as phosphorylase kinase
Phosphorylase kinase
Phosphorylase kinase is a serine/threonine-specific protein kinase which activates glycogen phosphorylase to release glucose-1-phosphate from glycogen...
, glycogen phosphorylase
Glycogen phosphorylase
Glycogen phosphorylase is one of the phosphorylase enzymes . Glycogen phosphorylase catalyzes the rate-limiting step in the degradation of glycogen in animals by releasing glucose-1-phosphate from the terminal alpha-1,4-glycosidic bond...
, and glycogen synthase
Glycogen synthase
Glycogen synthase is an enzyme involved in converting glucose to glycogen. It takes short polymers of glucose and converts them into long polymers....
.
This leads to phosphorylase kinase and glycogen phosphorylase's becoming inactive, while glycogen synthase is activated. As a result, glycogen
Glycogen
Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
synthesis is increased and glycogenolysis
Glycogenolysis
Glycogenolysis is the conversion of glycogen polymers to glucose monomers. Glycogen is catabolized by removal of a glucose monomer through cleavage with inorganic phosphate to produce glucose-1-phosphate...
is decreased, and the net effect is for energy to enter and be stored inside the cell.
Mechanism
Phosphorylation involves the transfer of phosphate groups from ATPAdenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
to the enzyme, the energy for which comes from hydrolysing ATP into ADP
Adenosine diphosphate
Adenosine diphosphate, abbreviated ADP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside adenosine. ADP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase adenine....
or AMP
Adenosine monophosphate
Adenosine monophosphate , also known as 5'-adenylic acid, is a nucleotide that is used as a monomer in RNA. It is an ester of phosphoric acid and the nucleoside adenosine. AMP consists of a phosphate group, the sugar ribose, and the nucleobase adenine...
.
However, dephosphorylation releases phosphates into solution as free ions, because attaching them back to ATP would require energy input.
Protein serine/threonine phosphatase
- PPP1CAPPP1CASerine/threonine-protein phosphatase PP1-alpha catalytic subunit is an enzyme that in humans is encoded by the PPP1CA gene.-Interactions:...
, PPP1CBPPP1CBSerine/threonine-protein phosphatase PP1-beta catalytic subunit is an enzyme that in humans is encoded by the PPP1CB gene.-Interactions:PPP1CB has been shown to interact with PPP1R15A, Nucleolin, SMARCB1 and PPP1R9B.-Further reading:...
, PPP1CCPPP1CCSerine/threonine-protein phosphatase PP1-gamma catalytic subunit is an enzyme that in humans is encoded by the PPP1CC gene.-Interactions:PPP1CC has been shown to interact with PPP1R15A, SMARCB1, TLX1 and PPP1R9B.-Further reading:...
, PPP2CAPPP2CASerine/threonine-protein phosphatase 2A catalytic subunit alpha isoform is an enzyme that in humans is encoded by the PPP2CA gene.-Interactions:...
, PPP2CBPPP2CBSerine/threonine-protein phosphatase 2A catalytic subunit beta isoform is an enzyme that in humans is encoded by the PPP2CB gene.-Interactions:PPP2CB has been shown to interact with TLX1, PPP2R1B and PPP2R1A.-Further reading:...
, PPP3CA, PPP3CBPPP3CBSerine/threonine-protein phosphatase 2B catalytic subunit beta isoform is an enzyme that in humans is encoded by the PPP3CB gene.-Further reading:...
, PPP3CCPPP3CCSerine/threonine-protein phosphatase 2B catalytic subunit gamma isoform is an enzyme that in humans is encoded by the PPP3CC gene.-Further reading:...
, PPP4CPPP4CSerine/threonine-protein phosphatase 4 catalytic subunit is an enzyme that in humans is encoded by the PPP4C gene.-Interactions:PPP4C has been shown to interact with CCT2, CCT4, CCT7, SMEK2, CCT6A, CCT3, IGBP1, PPP4R1, CCT5, T-complex 1, REL, CCDC6, TRAF6 and PPP2R1A.-Further reading:... - PPP5CPPP5CSerine/threonine-protein phosphatase 5 is an enzyme that in humans is encoded by the PPP5C gene.-Interactions:PPP5C has been shown to interact with ASK1, CRY2 GNA12. and Rac1,-Further reading:...
, PPP6CPPP6CSerine/threonine-protein phosphatase 6 catalytic subunit is an enzyme that in humans is encoded by the PPP6C gene.-Further reading:...
Protein tyrosine phosphatase
- CDC14s: CDC14ACDC14ADual specificity protein phosphatase CDC14A is an enzyme that in humans is encoded by the CDC14A gene.-Further reading:...
, CDC14BCDC14BDual specificity protein phosphatase CDC14B is an enzyme that in humans is encoded by the CDC14B gene.-Interactions:CDC14B has been shown to interact with p53.. However, this interaction has not been reported in other studies.-Further reading:...
, CDC14C, CDKN3CDKN3Cyclin-dependent kinase inhibitor 3 is an enzyme that in humans is encoded by the CDKN3 gene.-Interactions:CDKN3 has been shown to interact with Cyclin-dependent kinase 2, Cdk1 and MS4A3.-Further reading:... - Phosphatase and tensin homologs: PTENPTEN (gene)Phosphatase and tensin homolog is a protein that, in humans, is encoded by the PTEN gene. Mutations of this gene are a step in the development of many cancers....
- slingshot: SSH1SSH1For the SSH-1 protocol, see Secure Shell#Version 1.xProtein phosphatase Slingshot homolog 1 is an enzyme that in humans is encoded by the SSH1 gene.-Further reading:...
, SSH2SSH2For the SSH-2 protocol, see Secure Shell#Version 2.xProtein phosphatase Slingshot homolog 2 is an enzyme that in humans is encoded by the SSH2 gene.-Further reading:...
, SSH3SSH3Protein phosphatase Slingshot homolog 3 is an enzyme that in humans is encoded by the SSH3 gene.-Further reading:...
Dual-specificity phosphatase
- DUSP1DUSP1Dual specificity protein phosphatase 1 is an enzyme that in humans is encoded by the DUSP1 gene.-Interactions:DUSP1 has been shown to interact with MAPK14, MAPK1 and MAPK8.-Further reading:...
, DUSP2DUSP2Dual specificity protein phosphatase 2 is an enzyme that in humans is encoded by the DUSP2 gene.-Further reading:...
, DUSP3DUSP3Dual specificity protein phosphatase 3 is an enzyme that in humans is encoded by the DUSP3 gene.-Interactions:DUSP3 has been shown to interact with MAPK3 and MAPK1.-Further reading:...
, DUSP4DUSP4Dual specificity protein phosphatase 4 is an enzyme that in humans is encoded by the DUSP4 gene.-Further reading:...
, DUSP5DUSP5Dual specificity protein phosphatase 5 is an enzyme that in humans is encoded by the DUSP5 gene.-Further reading:...
, DUSP6DUSP6Dual specificity phosphatase 6, also known as DUSP6, is an enzyme that in humans is encoded by the DUSP6 gene.- Function :The protein encoded by this gene is a member of the dual specificity protein phosphatase subfamily. These phosphatases inactivate their target kinases by dephosphorylating both...
, DUSP7DUSP7Dual specificity protein phosphatase 7 is an enzyme that in humans is encoded by the DUSP7 gene.- Function :Dual-specificity phosphatases constitute a large heterogeneous subgroup of the type I cysteine-based protein-tyrosine phosphatase superfamily. DUSPs are characterized by their ability to...
, DUSP8, DUSP9 - DUSP10DUSP10Dual specificity protein phosphatase 10 is an enzyme that in humans is encoded by the DUSP10 gene.-Interactions:DUSP10 has been shown to interact with MAPK14 and MAPK8.-Further reading:...
, DUSP11, DUSP12DUSP12Dual specificity protein phosphatase 12 is an enzyme that in humans is encoded by the DUSP12 gene.-Further reading:...
, DUSP13DUSP13Dual specificity phosphatase 13 is an enzyme that in humans is encoded by the DUSP13 gene.- Function :Members of the protein tyrosine phosphatase superfamily cooperate with protein kinases to regulate cell proliferation and differentiation. This superfamily is separated into two families based on...
, DUSP14, DUSP15DUSP15Dual specificity protein phosphatase 15 is an enzyme that in humans is encoded by the DUSP15 gene.-Further reading:...
, DUSP16DUSP16Dual specificity protein phosphatase 16 is an enzyme that in humans is encoded by the DUSP16 gene.-Interactions:DUSP16 has been shown to interact with MAPK14 and MAPK8IP1.-Further reading:...
, DUSP18DUSP18Dual specificity protein phosphatase 18 is an enzyme that in humans is encoded by the DUSP18 gene.-Further reading:...
, DUSP19DUSP19Dual specificity protein phosphatase 19 is an enzyme that in humans is encoded by the DUSP19 gene.-Interactions:DUSP19 has been shown to interact with ASK1 and MAP2K7.-Further reading:... - DUSP21, DUSP22DUSP22Dual specificity protein phosphatase 22 is an enzyme that in humans is encoded by the DUSP22 gene.-Interactions:DUSP22 has been shown to interact with MAPK1 and MAPK8.-Further reading:...
, DUSP23DUSP23Dual specificity protein phosphatase 23, also known as low molecular mass dual specificity phosphatase 3 , is an enzyme that in humans is encoded by the DUSP23 gene....
, DUSP26, DUSP27, DUSP28
Ungrouped
- CTDP1CTDP1RNA polymerase II subunit A C-terminal domain phosphatase is an enzyme that in humans is encoded by the CTDP1 gene.-Interactions:CTDP1 has been shown to interact with WD repeat-containing protein 77, GTF2F1 and POLR2A.-Further reading:...
- CTDSP1CTDSP1Carboxy-terminal domain RNA polymerase II polypeptide A small phosphatase 1 is an enzyme that in humans is encoded by the CTDSP1 gene.-Further reading:...
, CTDSP2CTDSP2Carboxy-terminal domain RNA polymerase II polypeptide A small phosphatase 2 is an enzyme that in humans is encoded by the CTDSP2 gene.-Further reading:...
, CTDSPLCTDSPLCTD small phosphatase-like protein is an enzyme that in humans is encoded by the CTDSPL gene.-Further reading:... - DULLARD
- EPM2A
- ILKAPILKAPIntegrin-linked kinase-associated serine/threonine phosphatase 2C is an enzyme that in humans is encoded by the ILKAP gene.-Interactions:ILKAP has been shown to interact with Integrin-linked kinase.-Further reading:...
- MDSPMDSPMDSP is a multiprocessor DSP family from Cradle Technologies. Currently used mostly in streaming video processing in broadcast and video surveillance security markets...
- PGAM5
- PHLPP1, PHLPP2
- PPEF1PPEF1Serine/threonine-protein phosphatase with EF-hands 1 is an enzyme that in humans is encoded by the PPEF1 gene.-Interactions:PPEF1 has been shown to interact with Calmodulin 1.-Further reading:...
, PPEF2 - PPM1APPM1AProtein phosphatase 1A is an enzyme that in humans is encoded by the PPM1A gene.-Interactions:PPM1A has been shown to interact with Metabotropic glutamate receptor 3....
, PPM1BPPM1BProtein phosphatase 1B is an enzyme that in humans is encoded by the PPM1B gene.-Interactions:PPM1B has been shown to interact with IKBKG, IKK2, Cyclin-dependent kinase 2, Cyclin-dependent kinase 6, CHUK and MAP3K7.-Further reading:...
, PPM1DPPM1DProtein phosphatase 1D is an enzyme that in humans is encoded by the PPM1D gene.-Further reading:...
, PPM1E, PPM1FPPM1FProtein phosphatase 1F is an enzyme that in humans is encoded by the PPM1F gene.-Further reading:...
, PPM1GPPM1GProtein phosphatase 1G is an enzyme that in humans is encoded by the PPM1G gene.-Further reading:...
, PPM1H , PPM1J , PPM1KPPM1KProtein phosphatase 1K, mitochondrial is an enzyme that in humans is encoded by the PPM1K gene.-Further reading:...
, PPM1L , PPM1M , PPM1N - PPTC7
- PTPMT1
- SSU72
- UBLCP1