Fig. 2. AKAP149 does not co-precipitate with other known nuclear PP1 regulatory subunits. (A) Isolated nuclei and AKAP149-IPs from NEs were immunoblotted using antibodies against PP1, PNUTS, Sds22 and NIPP1. (B) 10 µM of AKAP149-derived RVXF or RAXF peptides were co-incubated with NIPP1-, PNUTS-, Sds22- or AKAP149-IPs for 1 hour, IPs were sedimented and dissociation of PP1 from the IPs was examined by western blotting of sedimented (P) and soluble (S) fractions.