Recombinant Human Serine/threonine-protein phosphatase 2A activator (PTPA)

Function

PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (By similarity). Acts as a regulatory subunit for serine/threonine-protein phosphatase 2A (PP2A) (PubMed:16916641, PubMed:36073231). Modulates PP2A activity or substrate specificity, probably by inducing a conformational change in the catalytic subunit, a proposed direct target of the PPIase (PubMed:16916641). Can reactivate inactive phosphatase PP2A-phosphatase methylesterase complexes (PP2A(i)) in presence of ATP and Mg(2+) (By similarity). Reversibly stimulates the variable phosphotyrosyl phosphatase activity of PP2A core heterodimer PP2A(D) in presence of ATP and Mg(2+) (in vitro) (PubMed:16916641). The phosphotyrosyl phosphatase activity is dependent of an ATPase activity of the PP2A(D):PPP2R4 complex (PubMed:16916641). Is involved in apoptosis; the function appears to be independent from PP2A (PubMed:17333320)

Subcellular Location

Cytoplasm; Nucleus

Disease Association

Parkinson disease 25, autosomal recessive early-onset, with impaired intellectual development (PARK25) : An autosomal recessive, early-onset form of Parkinson disease, a complex neurodegenerative disorder characterized by bradykinesia, resting tremor, muscular rigidity and postural instability, as well as by a clinically significant response to treatment with levodopa. The pathology involves the loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies (intraneuronal accumulations of aggregated proteins), in surviving neurons in various areas of the brain. PARK25 is characterized by onset of parkinsonism in late childhood or adolescence, developmental delay and intellectual disability. Cognitive impairment is mild to moderate and non-progressive. [The disease is caused by variants affecting the gene represented in this entry]

Tissue Specificity

Widely expressed

Subunit

Associates with PP2A heterodimeric core enzyme PP2A(D), composed of a 36 kDa catalytic subunit (subunit C) and a 65 kDa constant regulatory subunit (PR65 or subunit A) (PubMed:16916641). Interacts with the catalytic subunit PPP2CA (via C-terminus) (PubMed:25003389). Interacts with PPP2CB (By similarity)

• Cayla X. et al. Molecular cloning, expression, and characterization of PTPA, a protein that activates the tyrosyl phosphatase activity of protein phosphatase 2A. — J. Biol. Chem. (1994)
• Van Hoof C. et al. Structure and chromosomal localization of the human gene of the phosphotyrosyl phosphatase activator (PTPA) of protein phosphatase 2A. — Genomics (1995)
• Janssens V. et al. Identification and characterization of alternative splice products encoded by the human phosphotyrosyl phosphatase activator gene. — Eur. J. Biochem. (2000)
• Ota T. et al. Complete sequencing and characterization of 21,243 full-length human cDNAs. — Nat. Genet. (2004)
• Kalnine N. et al. Cloning of human full-length CDSs in BD Creator(TM) system donor vector. (OCT-)
• Suzuki Y. et al. PubMed: CI-5AVBODINQ93DF (APR-)
• Humphray S.J. et al. DNA sequence and analysis of human chromosome 9. — Nature (2004)
• Mural R.J. et al. PubMed: CI-5GBDQ6B103N1E (JUL-)