The inhibition of functional expression of calcium channels by prion protein demonstrates competition with α2δ for GPI-anchoring pathways
| Autor: | Anita, Alvarez-Laviada, Ivan, Kadurin, Assunta, Senatore, Roberto, Chiesa, Annette C, Dolphin |
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| Rok vydání: | 2013 |
| Předmět: |
GPI
glycosylphosphatidylinositol PrPSc PrP scrapie Glycosylphosphatidylinositols Prions Xenopus DRM detergent-resistant membrane Mice Transgenic Binding Competitive Mice Calcium Channels N-Type Animals Mice Knockout CaV voltage-gated Ca2+ HA haemagglutinin PrP prion protein GPI anchor KO knockout PNGase F peptide N-glycosidase F PI-PLC phosphatidylinositol-specific phospholipase C WT wild-type Rats Mice Inbred C57BL Protein Transport Gene Expression Regulation auxiliary subunit prion protein PrPC normal cellular PrP Female calcium channel MBS Mes-buffered saline Calcium Channels α2δ Protein Binding Signal Transduction Research Article |
| Zdroj: | Biochemical Journal |
| ISSN: | 1470-8728 |
| Popis: | It has been shown recently that PrP (prion protein) and the calcium channel auxiliary α2δ subunits interact in neurons and expression systems [Senatore, Colleoni, Verderio, Restelli, Morini, Condliffe, Bertani, Mantovani, Canovi, Micotti, Forloni, Dolphin, Matteoli, Gobbi and Chiesa (2012) Neuron 74, 300–313]. In the present study we examined whether there was an effect of PrP on calcium currents. We have shown that when PrP is co-expressed with calcium channels formed from CaV2.1/β and α2δ-1 or α2δ-2, there is a consistent decrease in calcium current density. This reduction was absent when a PrP construct was used lacking its GPI (glycosylphosphatidylinositol) anchor. We have reported previously that α2δ subunits are able to form GPI-anchored proteins [Davies, Kadurin, Alvarez-Laviada, Douglas, Nieto-Rostro, Bauer, Pratt and Dolphin (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 1654–1659] and show further evidence in the present paper. We have characterized recently a C-terminally truncated α2δ-1 construct, α2δ-1ΔC, and found that, despite loss of its membrane anchor, it still shows a partial ability to increase calcium currents [Kadurin, Alvarez-Laviada, Ng, Walker-Gray, D’Arco, Fadel, Pratt and Dolphin (2012) J. Biol. Chem. 1287, 33554–33566]. We now find that PrP does not inhibit CaV2.1/β currents formed with α2δ-1ΔC, rather than α2δ-1. It is possible that PrP and α2δ-1 compete for GPI-anchor intermediates or trafficking pathways, or that interaction between PrP and α2δ-1 requires association in cholesterol-rich membrane microdomains. Our additional finding that CaV2.1/β1b/α2δ-1 currents were inhibited by GPI–GFP, but not cytosolic GFP, indicates that competition for limited GPI-anchor intermediates or trafficking pathways may be involved in PrP suppression of α2δ subunit function. PrP, but not GPI-anchorless PrP, suppresses CaV2.1/β/α2δ-1 or α2δ-2 calcium channel currents. However, PrP does not inhibit CaV2.1/β currents formed with anchorless α2δ-1, rather than full-length α2δ-1. The results of the present study suggest that α2δ subunits and PrP may compete for GPI-anchor pathways. |
| Databáze: | OpenAIRE |
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