Supplementary Figure 1: T_reg cells exhibit greater PP2A activity than that of T_conv cells, and PP2A^flox mice develop multi-organ autoimmunity.

(a) The enzymatic activity of PP2A_C was quantified in CD4⁺CD25^- T_conv cells and CD4⁺CD25⁺ T_reg cells (n=5 per group). Data are from one experiment representative of two independent experiments with similar results. (b) Left: Real-time PCR of the Ppp2r1a and Ppp2r1b genes in unstimulated and stimulated naïve CD4⁺ T cells with CD3 plus CD28 antibodies (2μg/mL) for 24 hours. Each isoform was multiplexed separately in Taqman assays with the housekeeping gene Actb (n=3 per group). Right: Primer efficiency for the two isoforms with serial dilutions of the input DNA, demonstrating that the two PCRs retain efficiency over a wide range of DNA concentrations. (c) The appearance of PP2A^wt (left) and PP2A^flox (right) mice at 12 weeks of age. (d) Macroscopic and histologic image of a representative skin lesion of PP2A^flox mice. (e) Scaliness and crusting of the tail of PP2A^flox mice. (f) PP2A^flox mice that survived beyond 15 weeks of age (shown here at 19 weeks of age) developed significant skin disease with secondary ulceration. (g) The secondary lymphoid organs (upper: spleen, lower: peripheral lymph nodes) of PP2A^wt and PP2A^flox mice at 12 weeks of age. (h) Overt cervical lymphadenopathy in PP2A^flox mice. Images for (c-h) are from one experiment representative of at least three independent experiments with similar results. Mean ± s.e.m., *P<0.01 (unpaired, two-tailed t-test).