Eckman C B
Mayo Clinic, Jacksonville, Fl., USA.
J Neural Transm Suppl. 1998;53:181-4.
The presenilin proteins, localized predominantly to the endoplasmic reticulum, are multi-transmembrane spanning proteins that are processed to form an approximately 27 kD N-terminal fragment and a corresponding 19 kD C-terminal fragment. Mutations in the presenilin 1 and presenilin 2 genes have been identified that cause early onset familial Alzheimer's disease. Analysis of plasma and fibroblasts from patients revealed that these mutations increase the concentration of A beta 42. Cells and transgenic animals containing these mutations both give rise to increases in the extracellular concentration of this peptide providing further evidence for the role of A beta, particularly A beta 42, in Alzheimer's disease. These data provide strong evidence that alterations in A beta concentration are an early and critical event in the pathology of Alzheimer's disease.
早老素蛋白主要定位于内质网，是多次跨膜的蛋白质，经过加工形成一个约27kD的N端片段和一个相应的19kD的C端片段。早老素1和早老素2基因的突变已被确定可导致早发型家族性阿尔茨海默病。对患者血浆和成纤维细胞的分析显示，这些突变会增加β淀粉样蛋白42（Aβ42）的浓度。含有这些突变的细胞和转基因动物都会导致该肽细胞外浓度的增加，这为Aβ，特别是Aβ42在阿尔茨海默病中的作用提供了进一步的证据。这些数据提供了有力证据，表明Aβ浓度的改变是阿尔茨海默病病理过程中的一个早期关键事件。
