The B regulatory subunit might modulate substrate selectivity and catalytic activity, and also might direct the localization of the catalytic enzyme to a particular subcellular compartment. Essential for serine/threonine-protein phosphatase 2A-mediated dephosphorylation of WEE1, preventing its ubiquitin-mediated proteolysis, increasing WEE1 protein levels, and promoting the G2/M checkpoint. PP2A consists of a common heterodimeric core enzyme, composed of a 36 kDa catalytic subunit (subunit C) and a 65 kDa constant regulatory subunit (PR65 or subunit A), that associates with a variety of regulatory subunits. Proteins that associate with the core dimer include three families of regulatory subunits B (the R2/B/PR55/B55, R3/B''/PR72/PR130/PR59 and R5/B'/B56 families), the 48 kDa variable regulatory subunit, viral proteins, and cell signaling molecules (By similarity). Found in a complex with at least ARL2, PPP2CB, PPP2R1A, PPP2R2A, PPP2R5E and TBCD (By similarity). Interacts with TP53 (By similarity). Interacts with IER5 (By similarity). Interacts with MFHAS1; the interaction is direct (By similarity). Interacts with PABIR1/FAM122A (By similarity). Interacts with CRTC3 (By similarity). Brain. Belongs to the phosphatase 2A regulatory subunit B family.