siRNA-mediated knockdown of HSP90 expression results in decreased levels of mitochondrial Akt. (A) Cells stably transfected with HSP90 siRNA were lysed and immunoblotted for expression of HSP90, Akt, HSP70, HSC70, and HSP40. *p<0.05 compared with values from control cell line, Student’s t-test. (B) Cells transfected with HSP90 siRNA or control pcDNA plasmid were fractionated into cytosolic and mitochondrial fractions and the two fractions were immunoblotted for Akt. *p<0.05 compared with values from control cell line, Student’s t-test.