... B subunits in organisms as diverse as Neurospora crassa,Candida tropicalis, Dictyostelium discoideum, Medicagovaria (alfalfa), Arabidopsis t haliana, Oryza sativa (rice),Caenorhabditis elegans, ... enhanced degradationby intracellular proteases. One possibility is that these B5 6a fragments h ave substantially lower af®nity for the PP 2A ACheterodimer than does full-length B5 6a. As B5 6 subunitsover-expressed ... 3408, david.virshup@hci.utah.eduAbbreviations: PP 2A, protein phosphatase 2A; ASBD, A subunitbinding dom a in; GST -A, glu t athione S-transferase A s ubunit; NP-40,nonidet p40; CMV, cyto megalovirus.(Received...