Fig. 6: Combinatorial mechanisms used by B55-specific regulators, substrates and inhibitors contribute to PP2A:B55 phosphosite selectivity.
From: Cryo-EM structures of PP2A:B55 with p107 and Eya3 define substrate recruitment
a, Overlay of PP2A:B55 (B55 in lavender with interaction sites colored (platform, beige; wall, green; entry, pink; hook, yellow); PP2Ac, dark gray; PP2Aa, white) bound to p107 (salmon), eya3 (purple), FAM122A (orange), ARPP19 (dark blue) and IER5 (gray). The location of the PP2Ac catalytic pocket is indicated in red. b, Same as a, but individual complexes, separated by regulators or substrates and inhibitors. c, Location of individual binding pockets on B55, colored as in a. d, B55-interacting residues bound at B55 pockets P1, P2 and P4. B55 pocket residues, beige sticks; B55-interacting residues, sticks colored as in a. e, Same as d, but for B55 pocket P3. f, Same as d, but for B55 pockets P7–P9. g, B55 pockets, with residues defining the pockets indicated and the corresponding B55-interacting residues listed. h, Cartoon illustrating how B55-specific recruitment contributes to PP2A:B55 phosphosite dephosphorylation selectivity.
