C-terminal fragment of amyloid precursor protein inhibits calcium uptake into rat brain microsomes by Mg2+-Ca2+ ATPase.
Numerous lines of evidence suggest that some of the neurotoxicity associated with Alzheimer's disease (AD) is due to proteolytic fragments of the amyloid precursor protein (APP). Most research has focused on the amyloid beta peptide (A beta). However, the possible role of other cleaved products of APP is less clear. In this study, the effects of a recombinant carboxy terminal 105 amino acid (CT105) fragment of APP on the calcium uptake by endoplasmic reticulum Mg2+-Ca2+ ATPase, the major mechanism for sequestering calcium in this organelle, were investigated. We found that CT 105 is a potent inhibitor of Mg2+-Ca2+ ATPase of endoplasmic reticulum, whereas A beta shows no effect. These results demonstrate that CT 105 inhibits the ability of brain microsomes to sequester calcium and suggest that this inhibitory effect of CT 105 may contribute to disruption of intracellular calcium concentration, possibly being involved in inducing the neural toxicity characteristic of AD.
Kim
H S
HS
Department of Pharmacology, College of Medicine, Neuroscience Research Institute, Seoul National University, South Korea.
Park
C H
CH
Suh
Y H
YH
D016564:Amyloid beta-Protein Precursor / Q000737:chemistry*; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D008861:Microsomes / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium