I2PP2A/SET-GST
I2PP2A/SET-GST Source: Recombinant human kidney produced in E. coli
Purity: > 90% by SDS-PAGE, apparent Mr ~ 67-kDa
Supplied: In 50 μl 50 mM Tris-HCl pH 7.0 buffer containing 14 mM β-mercaptoethanol, 1 mM benzamidine, 0.1 mM phenylmethanesulfonyl fluoride, 1 mM EDTA, 0.1% Brij-35 and 10% glycerol. Maintain preparations in aliquots at -70° C. Avoid repeated thawing.
Synonyms: I2PP2A-GST; Protein Phosphatase 2A Inhibitor Protein 2; SET; PHAP-II; Taf-1β
GloboZymes I2PP2A/SET GST-tagged preparations maintain all known activities of the native I2PP2A/SET protein tested to date. The GST-tagged preparations can also be used for binding and pull-down studies.
Background: I2PP2A/SET is a potent inhibitor of Protein Phosphatase 2A (PP2A), a major mammalian protein serine/threonine phosphatase that regulates diverse cellular processes. Purified preparations of I2PP2A/SET inhibit all forms of the phosphatase tested to date in a substrate-selective manner. For example, the preparations inhibit PP2A potently (ki ~ 0.1 – 0.5 nM) with Myelin Basic Protein (MBP) and Histone H1 but not with casein as substrate. I2PP2A/SET was originally found to occur as a fusion protein with the nucleoporin CAN (NUP214) in a patient with acute undifferentiated leukemia. Elevated expression of I2PP2A/SET has since been shown to occur in numerous cancers. Transient expression of I2PP2A/SET in HEK-293 cells increases the DNA binding and AP1 activities of the proto-oncogene c-Jun. The sphingolipid second messenger cermaide binds to I2PP2A/SET and prevents it from inhibiting PP2A. This contributes, at least in part, to the mechanism by which Ceramide promotes apoptosis. I2PP2A/SET is multifunctional. It also prevents inhibition of E-CDK-2 by p21Cip1 and associates with B cyclin. It regulates histone binding to DNA, transcriptional activity and chromatin condensation. I2PP2A/SET undergoes phosphorylation at Ser9 and Ser24 in intact cells. The functional significance of these phosphorylations is uncertain. Some studies indicate that Ser9 phosphorylation may causes cytoplasmic detention of I2PP2A in Alzheimer disease.
References: Li M, Makkinje A, Damuni Z. (1996) J Biol Chem 271, 11059-11062; von Lindern, M. et al (1992) Mol Cell Biol 12, 3346-3355; Al-Murrani, S. W., Woodgett, J. R., and Damuni, Z. (1999) Biochem J. 341, 293–298; Li, M., Damuni, Z. (1998) Proteins” Methods Mol Biol 93, 59-66; Katayose, Y. et al (2000) J Biol Chem 275, 9209-9214
