title: Visualization of subunit interactions and ternary complexes of protein phosphatase 2A in mammalian cells.
abstract: Protein phosphatase 2A (PP2A) is a ubiquitous phospho-serine/threonine phosphatase that controls many diverse cellular functions. The predominant form of PP2A is a heterotrimeric holoenzyme consisting of a scaffolding A subunit, a variable regulatory B subunit, and a catalytic C subunit. The C subunit also associates with other interacting partners, such as α4, to form non-canonical PP2A complexes. We report visualization of PP2A complexes in mammalian cells. Bimolecular fluorescence complementation (BiFC) analysis of PP2A subunit interactions demonstrates that the B subunit plays a key role in directing the subcellular localization of PP2A, and confirms that the A subunit functions as a scaffold in recruiting the B and C subunits to form a heterotrimeric holoenzyme. BiFC analysis also reveals that α4 promotes formation of the AC core dimer. Furthermore, we demonstrate visualization of specific ABC holoenzymes in cells by combining BiFC and fluorescence resonance energy transfer (BiFC-FRET). Our studies not only provide direct imaging data to support previous biochemical observations on PP2A complexes, but also offer a promising approach for studying the spatiotemporal distribution of individual PP2A complexes in cells.
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Shu-Ting
authors.initials: ST
authors.lastname: Mo
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Shang-Ju
authors.initials: SJ
authors.lastname: Chiang
authors.affiliation: Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Tai-Yu
authors.initials: TY
authors.lastname: Lai
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Cheng
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Cheng-En
authors.initials: CE
authors.lastname: Chung
authors.affiliation: Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Spencer C H
authors.initials: SC
authors.lastname: Kuo
authors.affiliation: Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States of America.
authors.forename: Kelie M
authors.initials: KM
authors.lastname: Reece
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yung-Cheng
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Nan-Shan
authors.initials: NS
authors.lastname: Chang
authors.affiliation: Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States of America.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Wadzinski
authors.affiliation: Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chi-Wu
authors.initials: CW
authors.lastname: Chiang
mesh_terms: D000818:Animals; D005455:Fluorescent Antibody Technique; D051379:Mice; D041681:NIH 3T3 Cells; D055503:Protein Multimerization; D054648:Protein Phosphatase 2 / Q000032:analysis / Q000378:metabolism*; D021122:Protein Subunits / Q000032:analysis / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D054648:Protein Phosphatase 2