Key Spec Table
|Species Reactivity||Key Applications||Host||Format||Antibody Type|
|H, M||WB||M||Culture Supernatant||Monoclonal Antibody|
|Description||Anti-PTPA Antibody, clone 5G3|
|Application||Detect PTPA using this Anti-PTPA Antibody, clone 5G3 validated for use in WB.|
|Safety Information according to GHS|
|Storage and Shipping Information|
|Storage Conditions||2 years at -20°C from date of shipment|
|Material Size||100 µL|
|Anti-PTPA, clone 5G3 - 2482230||2482230|
|Anti-PTPA, clone 5G3 - 2542047||2542047|
|Anti-PTPA, clone 5G3 - 30532||30532|
|Anti-PTPA, clone 5G3 -2664257||2664257|
|Anti-PTPA, clone 5G3 -2784675||2784675|
|Reference overview||Pub Med ID|
|PP2A: the expected tumor suppressor.|
Janssens, Veerle, et al.
Curr. Opin. Genet. Dev., 15: 34-41 (2005) 2005
PP2A is one of the few serine/threonine-specific phosphatases in the cell, and its complex structure and regulation guarantees its many different functions. Some viruses have chosen to target this enzyme system in order to manage the host cell machinery for their own profit and to program cells into a malignant state. Suppression of PR61/B'gamma, a specific third regulatory subunit of PP2A, can substitute for the viral SV40 protein small t antigen in causing tumorigenic transformation of several human cell lines -- provided that telomerase, SV40 large T antigen and oncogenic Ras are also present. Accumulation of c-Myc seems to be the common denominator.
|The yeast phosphotyrosyl phosphatase activator is part of the Tap42-phosphatase complexes.|
Zheng, Yin and Jiang, Yu
Mol. Biol. Cell, 16: 2119-27 (2005) 2005
Phosphotyrosyl phosphatase activator PTPA is a type 2A phosphatase regulatory protein that possesses an ability to stimulate the phosphotyrosyl phosphatase activity of PP2A in vitro. In yeast Saccharomyces cerevisiae, PTPA is encoded by two related genes, RRD1 and RRD2, whose products are 38 and 37% identical, respectively, to the mammalian PTPA. Inactivation of either gene renders yeast cells rapamycin resistant. In this study, we investigate the mechanism underling rapamycin resistance associated with inactivation of PTPA in yeast. We show that the yeast PTPA is an integral part of the Tap42-phosphatase complexes that act downstream of the Tor proteins, the target of rapamycin. We demonstrate a specific interaction of Rrd1 with the Tap42-Sit4 complex and that of Rrd2 with the Tap42-PP2Ac complex. A small portion of PTPA also is found to be associated with the AC dimeric core of PP2A, but the amount is significantly less than that associated with the Tap42-containing complexes. In addition, our results show that the association of PTPA with Tap42-phosphatase complexes is rapamycin sensitive, and importantly, that rapamycin treatment results in release of the PTPA-phosphatase dimer as a functional phosphatase unit.
|An inactive protein phosphatase 2A population is associated with methylesterase and can be re-activated by the phosphotyrosyl phosphatase activator.|
Longin, Sari, et al.
Biochem. J., 380: 111-9 (2004) 2004
We have described recently the purification and cloning of PP2A (protein phosphatase 2A) leucine carboxylmethyltransferase. We studied the purification of a PP2A-specific methylesterase that co-purifies with PP2A and found that it is tightly associated with an inactive dimeric or trimeric form of PP2A. These inactive enzyme forms could be reactivated as Ser/Thr phosphatase by PTPA (phosphotyrosyl phosphatase activator of PP2A). PTPA was described previously by our group as a protein that stimulates the in vitro phosphotyrosyl phosphatase activity of PP2A; however, PP2A-specific methyltransferase could not bring about the activation. The PTPA activation could be distinguished from the Mn2+ stimulation observed with some inactive forms of PP2A, also found associated with PME-1 (phosphatase methylesterase 1). We discuss a potential new function for PME-1 as an enzyme that stabilizes an inactivated pool of PP2A.
|A novel and essential mechanism determining specificity and activity of protein phosphatase 2A (PP2A) in vivo.|
Fellner, Thomas, et al.
Genes Dev., 17: 2138-50 (2003) 2003
Protein phosphatase 2A (PP2A) is an essential intracellular serine/threonine phosphatase containing a catalytic subunit that possesses the potential to dephosphorylate promiscuously tyrosine-phosphorylated substrates in vitro. How PP2A acquires its intracellular specificity and activity for serine/threonine-phosphorylated substrates is unknown. Here we report a novel and phylogenetically conserved mechanism to generate active phospho-serine/threonine-specific PP2A in vivo. Phosphotyrosyl phosphatase activator (PTPA), a protein of so far unknown intracellular function, is required for the biogenesis of active and specific PP2A. Deletion of the yeast PTPA homologs generated a PP2A catalytic subunit with a conformation different from the wild-type enzyme, as indicated by its altered substrate specificity, reduced protein stability, and metal dependence. Complementation and RNA-interference experiments showed that PTPA fulfills an essential function conserved from yeast to man.
|Protein phosphatase 2A: a highly regulated family of serine/threonine phosphatases implicated in cell growth and signalling.|
Janssens, V and Goris, J
Biochem. J., 353: 417-39 (2001) 2001
Protein phosphatase 2A (PP2A) comprises a family of serine/threonine phosphatases, minimally containing a well conserved catalytic subunit, the activity of which is highly regulated. Regulation is accomplished mainly by members of a family of regulatory subunits, which determine the substrate specificity, (sub)cellular localization and catalytic activity of the PP2A holoenzymes. Moreover, the catalytic subunit is subject to two types of post-translational modification, phosphorylation and methylation, which are also thought to be important regulatory devices. The regulatory ability of PTPA (PTPase activator), originally identified as a protein stimulating the phosphotyrosine phosphatase activity of PP2A, will also be discussed, alongside the other regulatory inputs. The use of specific PP2A inhibitors and molecular genetics in yeast, Drosophila and mice has revealed roles for PP2A in cell cycle regulation, cell morphology and development. PP2A also plays a prominent role in the regulation of specific signal transduction cascades, as witnessed by its presence in a number of macromolecular signalling modules, where it is often found in association with other phosphatases and kinases. Additionally, PP2A interacts with a substantial number of other cellular and viral proteins, which are PP2A substrates, target PP2A to different subcellular compartments or affect enzyme activity. Finally, the de-regulation of PP2A in some specific pathologies will be touched upon.
|PTPA regulating PP2A as a dual specificity phosphatase.|
Janssens, V, et al.
Methods Mol. Biol., 93: 103-15 (1998) 1998