Protein serine/threonine phosphatase
| protein-serine/threonine phosphatase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 3.1.3.16 | ||||||||
| CAS number | 9025-75-6 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| |||||||||
Protein serine/threonine phosphatase (PSP)[1] is a form of phosphoprotein phosphatase that acts upon serine/threonine residues.
Serine and threonine phosphates are stable under physiological conditions, so a phosphatase has to remove the phosphate to reverse the regulation.
Ser/Thr-specific protein phosphatases are regulated by their location within the cell and by specific inhibitor proteins.
Serine and threonine are amino acids of similar composition. Serine is non-essential and can be synthesized in the body from threonine or some other amino acids and necessary vitamins and/or minerals. Serine is useful in cells and contributes to the cell’s flexibility in the cell membrane. It is also involved in DNA and RNA metabolism. Threonine is an amino acid found in certain meats, nuts, and seeds. It is also used to manufacture structural proteins and useful to propagate the immune system. Serine and threonine have similar side-chain compositions and thus can be phosphorylated by a single enzyme called serine/threonine protein kinase. The addition of the phosphate group can be reversed by an enzyme called serine/threonine phosphatase. The removal of the phosphate group helps to regulate many cellular pathways involved in cell proliferation, programmed cell death (apoptosis), embryonic development, and cell differentiation.
Examples
There are several known groups with numerous members in each:
- PPP1 (α, β, γ1, γ2)
- PPP2 (formerly 2A)
- PPP3 (formerly 2b, also known as calcineurin)
- PPP2C
- PPP4
- PPP5
- PPP6
(links are to the catalytic subunit)
All but PPP2C have sequence homology in the catalytic domain, but differ in substrate specificity.
References
- ↑ Shi Y (October 2009). "Serine/threonine phosphatases: mechanism through structure". Cell. 139 (3): 468–84. doi:10.1016/j.cell.2009.10.006. PMID 19879837.