Insoluble wild–type and protease–resistant mutant prion protein in brains of patients with inherited prion disease

Abstract

We studied prion proteins (PrP) in skin and brains of Libyan Jews carrying the E200K mutation who died of familial Creutzfeldt-Jakob disease (CJD). Unexpectedly, studies with brain showed that PrP molecules encoded both by the wild-type (wt) and mutant alleles exhibit altered properties characteristic of the prion protein associated with prion diseases (PrPSc). Using monospecific antisera, we found that wtPrP was insoluble in the brains of three patients who were heterozygous for the E200K mutation, whereas mutant PrP was both insoluble and protease-resistant. Our results argue that both wild-type and mutant PrP undergo conformational changes and are particularly intriguing, because the normal isoform PrPc is soluble in nondenaturing detergents and is readily digested by proteases, whereas PrPSc is insoluble and resistant to proteolytic digestion. Our findings indicate that insoluble wtPrP represents a conformational intermediate, the first to be identified, within a pathway in which PrPc is converted to PrPSc.

A Protease-resistant Prion Protein Isoform Is Present in Urine of Animals and Humans Affected with Prion Diseases

“…Most of the CJD patients tested in this work (6 of 8) were genetic patients carrying the E200K mutation (15)(16)(17)(18). One of the patients was a 52-year-old individual homozygous for this mutation (19).…”

A C-terminal-truncated PrP Isoform Is Present in Mature Sperm

“…To further delineate the site of such a putative C-terminal trimming, human mature sperm samples were immunoblotted with an antiserum raised against a synthetic peptide comprising residues 195-213 of the human and mouse PrP sequence (1E) and that has been shown to preferentially recognize the glutamate residue at position 200 (21). As can be seen in Fig.…”

“…1 shows anti PrP immunoblots of sperm cells extracts, either mature (human, bovine) or from the epididymis (hamster, mouse, and bovine), as compared with brain membranes of the same species. The antibodies used were 3F4 (directed against residues 108 -111) for human and hamsters (20), 6H4 ("Prionics," directed against residues 144 -152) for bovine samples, 1E (against residue 200 in humans and mice) (21), and R073 (polyclonal anti-PrP antisera reacting mostly against mouse and hamster PrP (22)). The molecular weight of PrP in semi-mature (epididymis) sperm cells was similar to that of the brain, whereas in mature sperm cells obtained from ejaculates, it appears as if the apparent M r of PrP was reduced to 24,000.…”

Interactions between wild-type and mutant prion proteins modulate neurodegeneration in transgenic mice.

“…Whether all cases of GSS (P102L) will transmit disease to Tg(MHu2M-P102L) mice expressing a mutant, chimeric Hu/Mo PrP transgene remains to be established (Telling et al 1995). It is also of interest that the brains of patients who die of inherited CJD (E200K) have two forms of insoluble PrP; the mutant PrP is protease resistant, and the wild-type is sensitive to protease digestion (Gabizon et al 1996). Yet, both the mutant and wild-type insoluble PrP can be dis tinguished from PrP*^ which is soluble in non-denaturing detergents.…”