title: Phosphatase: PP2A structural importance, regulation and its aberrant expression in cancer.
abstract: Protein Phosphatase 2A (PP2A) is an important and ubiquitously expressed serine threonine phosphatase and regulates the function by dephosphorylating many critical cellular molecules like Akt, p53, c-Myc and β-catenin. It plays a critical role in cellular processes, such as cell proliferation, signal transduction and apoptosis. Structurally, it is multifarious as it is composed of catalytic, scaffold and regulatory subunits. The catalytic and scaffold subunits have two isoforms and the regulatory subunit has four different families containing different isoforms. The regulatory subunit is the most diverse with temporal and spatial specificity. PP2A undergoes post-translational modifications (i.e. phosphorylation and methylation), which in turn, regulates its enzymatic activity. Aberrant expression, mutations and somatic alterations of the PP2A scaffold and regulatory subunits have been observed in various human malignancies, including lung, breast, skin and colon cancer, highlighting its role as a 'tumor suppressor'. This review is focused on the structural complexity of serine/threonine phosphatase PP2A and summarizes its expression pattern in cancer. Additionally, the PP2A interacting and regulatory proteins and substrates are also discussed. Finally, the mouse models developed to understand the biological role of PP2A subunits in an in vivo model system are also reviewed in this article.
authors: Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA. p.seshacharyulu@unmc.edu
authors: Parthasarathy
authors: P
authors: Seshacharyulu
authors: Poomy
authors: P
authors: Pandey
authors: Kaustubh
authors: K
authors: Datta
authors: Surinder K
authors: SK
authors: Batra
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D017124:Conserved Sequence; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009369:Neoplasms / Q000201:enzymology*; D054648:Protein Phosphatase 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D021122:Protein Subunits; D054648:Protein Phosphatase 2