| Infection with adenovirus 5 expressing PP2Calpha WT increased phosphatidylinositol 3 kinase ( PI3K ) activities in the immunoprecipitate using antibody against the p 85 or p 110 subunit under both basal and insulin stimulated conditions , followed by activation of downstream steps in the PI3K pathway , such as phosphorylation of Akt , glycogen synthase kinase 3 , and atypical protein kinase C . ^^^ Furthermore , overexpression of PP2Calpha WT ( but not PP2Calpha ( R174G ) ) decreased the ( 32 ) P labeled phosphorylation state as well as the gel mobility shift of the p 85 subunit , suggesting that dephosphorylation of the p 85 subunit by PP2Calpha activation might stimulate PI3K catalytic activity . ^^^ In conclusion , PP2Calpha is a new positive regulator of insulin sensitivity that acts through a direct activation of PI3K in 3T3 L 1 adipocytes . . ^^^ |