Effects of Δp85 on insulin-induced activation of signaling molecules and gene expression in the liver. (a) DNPI3K and LacZ mice were deprived of food for 16 hours and then injected with insulin (+) or saline (–). The liver was removed 2 minutes later, homogenized, and subjected to immunoprecipitation (IP) with antibodies to the IR, to IRS-1, or to IRS-2. The resulting precipitates were subjected to immunoblot analysis with the same respective antibodies or with antibodies to phosphotyrosine (PY). Data are shown for two mice per condition and are representative of results obtained from six mice. (b) Immunoprecipitates prepared with antibodies to IRS-1 or to IRS-2 as in a were assayed for PI 3-K activity. Data are means ± SEM of values from four mice. *P < 0.05, **P < 0.01 versus the corresponding value for LacZ mice. (c) Total RNA isolated from the liver of DNPI3K and of LacZ mice was subjected to Northern blot analysis with probes for the indicated mRNAs. Data are shown for three mice of each group. (d) Liver homogenates prepared as in a were subjected directly to immunoblot analysis with antibodies specific for phosphorylated Akt (pAkt) or for total Akt protein. Data are representative of results obtained from six mice.