PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Acts as a regulatory subunit for serine/threonine- protein phosphatase 2A (PP2A) modulating its activity or substrate specificity, probably by inducing a conformational change in the catalytic subunit, a proposed direct target of the PPIase. Can reactivate inactive phosphatase PP2A-phosphatase methylesterase complexes (PP2A(i)) in presence of ATP and Mg(2+). Reversibly stimulates the variable phosphotyrosyl phosphatase activity of PP2A core heterodimer PP2A(D) in presence of ATP and Mg(2+) (in vitro). The phosphotyrosyl phosphatase activity is dependent of an ATPase activty of the PP2A(D):PPP2R4 complex. Is involved in apoptosis; the function appears to be independent from PP2A. 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). Interacts with PPP2CB. Widely expressed. Belongs to the PTPA-type PPIase family. 4 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: EC 184.108.40.206; Protein phosphatase, regulatory subunit; Motility/polarity/chemotaxis
Cellular Component: protein phosphatase type 2A complex; cytoplasm; nucleolus; nucleus
Molecular Function: protein homodimerization activity; peptidyl-prolyl cis-trans isomerase activity; protein phosphatase 2A binding; protein heterodimerization activity; ATPase activity; protein phosphatase type 2A regulator activity; protein tyrosine phosphatase activator activity; ATP binding; receptor binding
Biological Process: ATP catabolic process; positive regulation of phosphoprotein phosphatase activity; negative regulation of protein amino acid dephosphorylation; protein peptidyl-prolyl isomerization; protein folding; positive regulation of apoptosis; mitotic spindle organization and biogenesis in nucleus; negative regulation of phosphoprotein phosphatase activity; regulation of phosphoprotein phosphatase activity; positive regulation of protein amino acid dephosphorylation
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.