Figure 3.

MEK1 Ablation Leads to Systemic Autoimmune Disease

(A) Enlarged glomeruli (arrows), tubules filled with proteinaceous material (asterisk), and increased pAKT in KO kidneys. Scale bars represent 100 μm.

(B) Immune complex deposition in the glomerulus of a 10-month-old KO female visualized by mouse IgG antibodies (green). The scale bar represents 30 μm.

(C) dsDNA autoantibodies detected in the serum of KO mice (5–10 months, n = 7) by Crithidia luciliae kinetoplast staining.

(D) IgG1, IgG2b, and IgA levels in the sera of 8- to 10-month-old mice (n = 3) assessed by ELISA.

(E) Frequency of B cells secreting IgA and IgG in 8- to 10-month-old mice determined by ELISpot (n = 4). Error bars represent the SD.

(F) BAFF and IL-10 serum levels determined as in (D).

(G) AKT phosphorylation and expression of AKT, MEK1, and GAPDH (loading control) were determined in lysates of 8-week-old WT and KO spleens.

(H) PTEN, MEK1, GAPDH (cytosolic marker), and caveolin (membrane marker) detected by immunoblotting in subcellular fractions of freshly isolated WT and KO splenocytes.

(I) Splenic CD4+ T cells stimulated with anti-CD3 and anti-CD28 (3 μg/ml each). The indicated proteins were visualized by immunoblotting.

(J–L) Survival of CD4+ T cells and B cells in response to AICD and FasL-induced cell death.

Values represent the mean of three experiments ±SD. ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001. See also Figure S3.