Open AccessVisualization of Subunit Interactions and Ternary Complexes of Protein Phosphatase 2A in Mammalian Cells
Author(s) -
Shu-Ting Mo,
Shang-Ju Chiang,
Tai-Yu Lai,
Ya-Yun Cheng,
Cheng-En Chung,
Spencer C. H. Kuo,
Kelie Reece,
Yung-Cheng Chen,
NanShan Chang,
Brian E. Wadzinski,
Chi-Wu Chiang
Publication year - 2014
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0116074
Subject(s) - bimolecular fluorescence complementation , heterotrimeric g protein , protein subunit , protein phosphatase 2 , förster resonance energy transfer , yellow fluorescent protein , microbiology and biotechnology , protein–protein interaction , biology , phosphatase , chemistry , biophysics , biochemistry , phosphorylation , fluorescence , g protein , signal transduction , gene , physics , quantum mechanics
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.