Open AccessTwo conserved domains in regulatory B subunits mediate binding to the A subunit of protein phosphatase 2A
Author(s) -
Li Xinghai,
Virshup David M
Publication year - 2002
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.0014-2956.2001.02680.x
Subject(s) - protein phosphatase 2 , protein subunit , heterotrimeric g protein , biology , specificity factor , phosphatase , conserved sequence , serine , gamma aminobutyric acid receptor subunit alpha 1 , genetics , gene , peptide sequence , biochemistry , g alpha subunit , phosphorylation , promoter , g protein , gene expression , signal transduction
Protein phosphatase 2A (PP2A) is an abundant heterotrimeric serine/threonine phosphatase containing highly conserved structural (A) and catalytic (C) subunits. Its diverse functions in the cell are determined by its association with a highly variable regulatory and targeting B subunit. At least three distinct gene families encoding B subunits are known: B/B55/CDC55, B′/B56/RTS1 and B″/PR72/130. No homology has been identified among the B families, and little is known about how these B subunits interact with the PP2A A and C subunits. In vitro expression of a series of B56α fragments identified two distinct domains that bound independently to the A subunit. Sequence alignment of these A subunit binding domains (ASBD) identified conserved residues in B/B55 and PR72 family members. The alignment successfully predicted domains in B55 and PR72 subunits that similarly bound to the PP2A A subunit. These results suggest that these B subunits share a common core structure and mode of interaction with the PP2A holoenzyme.