Expression of heat shock proteins in Alzheimer's disease.

In an investigation of heat shock proteins (HSPs) in the brains of Alzheimer's disease (AD) patients and cognitively intact control subjects, we found that 2 HSPs, termed "HSP72" and "GRP78," underwent major changes in expression in AD. HSP72, which was present at very low levels in control brains, increased dramatically in AD patients, and was localized exclusively in neuritic plaques and neurofibrillary tangles. We hypothesize that HSP72 is induced as an early response to the formation of abnormal proteins, perhaps targeting them for proteolysis.

Isolation and identification of a polypeptide in the Hsp 70 family that binds substance P.

During the course of an attempt to purify the substance P (SP) receptor from horse salivary glands by substance P-affinity chromatography, a polypeptide of Mr = 78,000 was isolated. The first fifteen amino acid residues at the amino terminus were determined and, unexpectedly, were found to be identical with the amino terminus of a glucose-regulated protein (GRP) of the same molecular weight, a protein that has been identified as a member of the heat shock protein family. This finding raises the intriguing possibility that SP may interact in vivo with GRPs and other members of the heat shock protein family and play a role in modulating their biological activities.

Location of a polypeptide sequence within the alpha-subunit of the acetylcholine receptor containing the cholinergic binding site.

Proteolytic fragments of the alpha-subunit of the acetylcholine receptor of Torpedo electric organ were generated by digestion with Staphylococcus aureus V8 protease, and their ability to bind alpha-bungarotoxin was assessed following resolution on polyacrylamide gels and transfer to nitrocellulose. The position of the smallest fragment (Mr = 17,000) with toxin-binding activity was located within the primary sequence of the alpha-subunit by isolation and chemical characterization. The amino acid sequence at its amino terminus is Val-Asn-Gln-Ile-Val-Glu, which is identical to a unique sequence on the alpha-subunit beginning at Val 46.

Analysis of receptor-ligand interactions using nitrocellulose gel transfer: application to Torpedo acetylcholine receptor and alpha-bungarotoxin.

A nitrocellulose-gel transfer technique has been adapted to study the interaction of a polypeptide ligand with individual receptor subunits. The acetylcholine receptor isolated from Torpedo californica has been separated into its subunits by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred in a renaturing environment to nitrocellulose sheets. The sheets were incubated with 125I-alpha-bungarotoxin and autoradiographed.