Figure 8 : Protein tyrosine phosphatase activity is enhanced in PrPC-null mice and zinc uptake is reduced in prion disease.

From: Prion protein facilitates uptake of zinc into neuronal cells

Figure 8

(a) Lysates from untransfected SH-SY5Y cells (Un) or cells expressing PrPC were incubated with phosphopeptide for 45 min at 37 °C to measure tyrosine phosphatase activity. Data shown as mean (±s.e.m.) (n=3). Independent Student's t-test, **P<0.01. (b) Tyrosine phosphatase activity was measured in whole-brain homogenate from wild-type 129/P2 (WT) or 129/P2 PrP−/− mice. Data shown as mean (±s.e.m.; n=8). Independent Student's t-test, *P<0.05. (c) SH-SY5Y cells expressing the various disease-associated mutants of PrPC were exposed to 100 μM Zn2+ and stained using 10 μM Zinpyr-1. Data shown as mean (±s.e.m.). Zinpyr-1 fluorescence corrected against DNA content (n=8). Kruskal–Wallis, **P<0.01. Insert shows expression of the various disease-associated mutants of PrPC. Lane 1, wild-type PrPC; lane 2, PG14; lane 3, A116V; lane 4, P101L; lane 5, D177N/M128; and lane 6, D117N/V128. Molecular weight marker in kDa. (d) Co-immunoprecipitation from P101 L, D177N (M128), D177N (V128) mouse brain or SH-SY5Y cell lysates expressing PG14 or A116V using antibodies against PrPC (6H4), control rabbit anti-mouse IgG or no antibody for the bead-only control, and then probed with antibodies against PrPC (SAF32), GluA1 or GluA2 as indicated. Zinc uptake measured using Newport Green in (e) uninfected N2a cells and (f) scrapie-infected ScN2a cells, either not supplemented with Zn2+ (light blue symbols) or supplemented with 32 μM Zn2+ (dark blue symbols). Data shown as the relative Newport Green fluorescence corrected against DNA content and plotted as mean±s.e.m. (n=3). Kruskal–Wallis, P<0.05 in the uninfected cells.