NR AOXD
AU Moya,K.L.; Hässig,R.; Laffont,I.
TI Membrane domains of peripheral nerve containing PrPc
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-63
PT Konferenz-Poster
AB
PrPc from brain is present in "raft-like" light density detergent resistant membrane domains (LDDRMs). In sciatic nerve we have described 36kD and 33 kD stationary forms of PrPc and a novel 38kD form that is axonally transported. In light of reports that TSE infectivity may gain entry into the CNS via peripheral nerves and that membrane microdomains may be a site of PrPc-PrPres conversion, we now asked: 1) what is the membrane compartment of the axonal PrP in nerve, specifically, is axonal PrP in "raft" microdomains? And 2) what is the membrane compartment of the transported axonal PrP in nerve?
Solubilization of hamster brain in 1% Triton X100 followed by sucrose gradient flotation centrifugation yielded GM1 enriched LDDRMs containing PrPc in light fractions 8-11 and PrPc in heavy fractions 17-21. However, LDDRMs were not detectable in sciatic nerve. Two % Tx100 had no effect on brain LDDRMs but did release LDDRMs from sciatic nerve. These were present in fractions 5-10 and thus lighter in density than those from brain. Using 2% Tx100 we then analyzed nerve segments proximal to a test section and that contain accumulated 38kD transported PrPc. Whereas stationary 36kD and 33kD PrPc were readily detectable in the LDDRM-containing fractions, 38kD PrPc was undetectable although 38kD PrPc was detected in the heavy fractions (17-21) and abundant in the insoluble pellet.
These results show that PrPc from sciatic nerve is in a DRM compartment less dense than brain PrPc. In addition, the compartment containing PrPc is not released from the homogenate with 1% but is released with 2% Triton X-100 suggesting that the lipids of the membrane domain surrounding the compartment are more highly ordered than in brain. Accumulated axonally transported PrPc is in a membrane domain highly resistant to detergent and does not partition into LDDRM. Thus, 38kD PrPc does not appear to be transported in a LDDRM. Support: GIS "Infections à prions".
AD Kenneth L. Moya, Raymonde Hässig, Isabelle Laffont, CEA-CNRS URA 2210, Service Hospitalier Frederic Joliot, France
SP englisch
PO Deutschland