Ultrastructural localization of prion proteins: Physiological and pathological implications

• Published in: Microscopy research and technique 2000-07, Vol.50 (1), p.76-88
• Main Authors: Fournier, Jean-Guy, Escaig-Haye, Françoise, Grigoriev, Vladimir
• Format: Article
• Language: English
• Subjects: amyloid plaques; Animals; Brain - metabolism; Brain - ultrastructure; Cricetinae; Cytoplasmic Granules - metabolism; Cytoplasmic Granules - ultrastructure; Epithelial Cells - metabolism; Epithelial Cells - ultrastructure; Humans; immuno-electron microscopy; Lysosomes - metabolism; Lysosomes - ultrastructure; Microscopy, Immunoelectron; Muscle, Skeletal - metabolism; Muscle, Skeletal - ultrastructure; Nerve Tissue - metabolism; Nerve Tissue - ultrastructure; Neuromuscular Junction - metabolism; non-neural tissues; Plaque, Amyloid - metabolism; Plaque, Amyloid - ultrastructure; prion diseases; Prion Diseases - metabolism; Prion Diseases - physiopathology; Prions - analysis; Prions - physiology; Protein Isoforms - analysis; Protein Isoforms - ultrastructure; Sheep; synapse; Synapses - metabolism; Synapses - ultrastructure
• ISSN: 1059-910X; 1097-0029
• DOI: 10.1002/1097-0029(20000701)50:1<76::AID-JEMT11>3.0.CO;2-#

The transmissible spongiform encephalopathies (TSE) or prion diseases are fatal neurodegenerative disorders in which the central event is the conversion of a normal host‐encoded protein (PrPc) into an abnormal isoform (PrPsc) which accumulates as amyloid in TSE brain. The two PrPc and PrPsc prion protein isoforms are membrane sialoglycoproteins synthesized in the central nervous system and various peripheral organ tissues. In this review, we describe the ultrastructural localization of prion proteins in human and animal cerebral and non‐cerebral tissues whether or not infected by TSE agents. In addition to the plasma membrane of several cells, PrPc was found in association with cytoplasmic organelles of central and nerve‐muscle synapses, and secretory granules of epithelial cells. Fibrils of amyloid plaques, synaptic structures, and lysosome‐like organelles constitute the subcellular sites harboring PrPsc. These findings have led to discussions on the physiological role of PrPc and the pathological mechanisms underlying prion spongiform encephalopathies. Microsc. Res. Tech. 50:76–88, 2000. © 2000 Wiley‐Liss, Inc.