GPI-anchor signal sequence influences PrPC sorting, shedding and signalling, and impacts on different pathomechanistic aspects of prion disease in mice
Fig 2
PrPCGPIThy-1 shows altered sorting.
(A) Confocal microscopy showing expression of WTPrPC and PrPCGPIThy-1 (green) in fully polarized MDCK epithelial cells. ZO1 (red) is expressed at the tight junction and delimitates the apical (a)/basolateral (b) side. Note that PrPCGPIThy-1 relocalizes to the apical side compared to WTPrPC, which is predominantly basolaterally located (scale bar is 5 μm). (B) Confocal microscopy of primary neuronal cultures stained with an antibody against PrP (POM1; green) under non-permeabilizing conditions. Both WTPrPC and PrPCGPIThy-1 are expressed at the plasma membrane (scale bars are 10 μm). (C) Representative confocal microscopy pictures of primary neuronal cultures stained with antibodies against PrP (POM1; green) and tau (red). (i) The squares indicate selected areas of the dendrites (where tau is absent) showing decreased PrPCGPIThy-1 amounts whereas staining is present in WTPrPC. (ii) Same staining as in (i) but focusing on tau-positive axons (the squares indicate magnifications where the relative increase in PrP staining at the axons in PrPCGPIThy-1 neurons can be observed). (iii) Bar diagram of a semi-automated quantification showing that the amount of PrPCGPIThy-1 present in tau-positive axons is significantly increased compared to WTPrPC (***p = 0.0001).