Figure 6. Immunoblot analysis of PP2B expression in mock, sense and antisense PP2B transfectants.

Undifferentiated (Undiff) and differentiated (Diff) NG108-15 cells (10 μg protein) were treated as described in the Methods. Anti-PP2B IgG was used at a dilution of 1/1000, as with immunocytochemical experiments. A major band of about 58 kDa was detected (arrow), corresponding to the shorter of two mammalian PP2B isoenzymes PP2B-A2. Mock-transfected cells (wild-type (WT)) were compared with cells transfected with sense (CN-15) or antisense (CN-21) constructs of PP2Bβ₃ (HT6/6) cDNA. Higher molecular weight bands correspond to tightly bound PP2B-A and PP2B-B oligomers that are recalcitrant to dissociation under the solubilization conditions used.