Protein Phosphatase 2a Activator, Regulatory Subunit 4 (PPP2R4) Antibody – Rabbit Polyclonal

Protein phosphatase 2A is one of the four major Ser/Thr phosphatases and is implicated in the negative control of cell growth and division. Protein phosphatase 2A holoenzymes are heterotrimeric proteins composed of a structural subunit A, a catalytic subunit C, and a regulatory subunit B. The regulatory subunit is encoded by a diverse set of genes that have been grouped into the B/PR55, B'/PR61, and B''/PR72 families. These different regulatory subunits confer distinct enzymatic specificities and intracellular localizations to the holozenzyme. The product of this gene belongs to the B' family. This gene encodes a specific phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase 2A. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

PPP2R4: 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.

Protein type: EC 5.2.1.8; Motility/polarity/chemotaxis; Protein phosphatase, regulatory subunit

Chromosomal Location of Human Ortholog: 9q34.11

Cellular Component: cytoplasm; nucleoplasm; nucleus; protein phosphatase type 2A complex

Molecular Function: ATP binding; ATPase activity; peptidyl-prolyl cis-trans isomerase activity; protein binding; protein heterodimerization activity; protein homodimerization activity; protein phosphatase 2A binding; protein phosphatase regulator activity; protein tyrosine phosphatase activator activity; receptor binding

Biological Process: mitotic spindle organization and biogenesis in nucleus; negative regulation of phosphoprotein phosphatase activity; negative regulation of protein dephosphorylation; positive regulation of apoptosis; positive regulation of phosphoprotein phosphatase activity; positive regulation of protein dephosphorylation; protein peptidyl-prolyl isomerization; regulation of phosphoprotein phosphatase activity