Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Victoria, Australia.
J Neurochem. 2010 Mar;112(5):1199-209. doi: 10.1111/j.1471-4159.2009.06540.x. Epub 2009 Dec 10.
Aggregation of beta-amyloid protein (Abeta) to form oligomers is considered to be a key step in generating neurotoxicity in the Alzheimer's disease brain. Agents that bind to Abeta and inhibit oligomerization have been proposed as Alzheimer's disease therapeutics. In this study, we investigated the binding of fluorescein-labeled Abeta(1-42) (FluoAbeta(1-42)) to SH-SY5Y neuroblastoma cells and examined the effect of the 39-kDa receptor-associated protein (RAP), on the Abeta cell interaction. FluoAbeta(1-42) bound to the cells in a punctate pattern. Surprisingly, when RAP was added to the incubations, FluoAbeta(1-42) and RAP were found to be co-localized on the cell surface, suggesting that RAP and Abeta may bind to each other. Experiments using the purified proteins confirmed that a RAP-Abeta complex was stable and resistant to sodium dodecyl sulfate. RAP also inhibited Abeta oligomerization. We next examined whether RAP could inhibit the neurotoxic effects of Abeta. Addition of Abeta(1-42) to SH-SY5Y cells caused an increase in intracellular Ca2+ that was inhibited by treatment of the Abeta peptide with RAP. RAP also blocked an Abeta-induced inhibition of long-term memory consolidation in 1-day-old chicks. This study demonstrates that RAP binds to Abeta and is an inhibitor of the neurotoxic effects of Abeta.
β-淀粉样蛋白（Abeta）的聚集形成寡聚体被认为是在阿尔茨海默病大脑中产生神经毒性的关键步骤。已经提出了与 Abeta 结合并抑制寡聚化的药物作为阿尔茨海默病的治疗方法。在这项研究中，我们研究了荧光素标记的 Abeta(1-42)（FluoAbeta(1-42)）与 SH-SY5Y 神经母细胞瘤细胞的结合，并检查了 39 kDa 受体相关蛋白（RAP）对 Abeta 细胞相互作用的影响。FluoAbeta(1-42)以点状模式与细胞结合。令人惊讶的是，当将 RAP 添加到孵育物中时，发现 FluoAbeta(1-42)和 RAP 在细胞表面上共定位，这表明 RAP 和 Abeta 可能相互结合。使用纯化蛋白进行的实验证实 RAP-Abeta 复合物是稳定的且耐受十二烷基硫酸钠。RAP 还抑制了 Abeta 的寡聚化。接下来，我们检查了 RAP 是否可以抑制 Abeta 的神经毒性作用。Abeta(1-42)添加到 SH-SY5Y 细胞中会导致细胞内 Ca2+增加，而用 RAP 处理 Abeta 肽可抑制这种增加。RAP 还阻止了 Abeta 诱导的 1 日龄小鸡长期记忆巩固的抑制。这项研究表明 RAP 与 Abeta 结合并且是 Abeta 神经毒性作用的抑制剂。
