FIGURE 6.
Desialylated GPIs do not target synapses. A, GPIs derived from neuronal PrPC (○) and desialylated GPIs (●) eluted from C18 columns. Values are means of duplicates. B, GPIs derived from neuronal PrPC (lane 1) and desialylated GPIs (lane 2) separated by HPTLC. C, amounts of FITC in synaptosomes from neurons incubated for 2 h with FITC-labeled GPIs as shown. Values are means ± S.D. (error bars) from triplicate experiments performed twice (n = 6). D, amounts of FITC in synaptosomes from neurons incubated for 2 h with 10 nm FITC alone (□) or with 10 nm FITC-labeled GPIs (■) or 10 nm FITC-desialylated GPIs (striped bar). Values are means ± S.D. from triplicate experiments performed twice (n = 6). E, concentrations of PrPC in synaptosomes isolated from Prnp(0/0) neurons pretreated with control medium (□) or GPIs as shown (■) and incubated with 10 nm PrPC. Values are means ± S.D. from triplicate experiments performed two times (n = 6). *, significantly less synaptic PrPC than in control synaptosomes. F, concentrations of PrPC in synaptosomes isolated from Prnp(0/0) neurons pretreated with control medium (□), 10 nm GPIs (■), or 10 nm desialylated GPIs (striped bar) and incubated with 10 nm PrPC. Values are means ± S.D. from triplicate experiments performed two times (n = 6). *, significantly less synaptic PrPC than in control synaptosomes.