Cross-Sequence Interactions between Human and Rat Islet Amyloid Polypeptides

详细信息    查看全文

• 作者：Rundong Hu ; Mingzhen Zhang ; Kunal Patel ; Qiuming Wang ; Yung Chang ; Xiong Gong ; Ge Zhang ; Jie Zheng
• 刊名：Langmuir
• 出版年：2014
• 出版时间：May 13, 2014
• 年：2014
• 卷：30
• 期：18
• 页码：5193-5201
• 全文大小：418K
• 年卷期：v.30,no.18(May 13, 2014)
• ISSN：1520-5827

文摘

Human islet amyloid polypeptide (hIAPP) can assemble into toxic oligomers and fibrils, which are associated with cell degeneration and the pathogenesis of type 2 diabetes. Cross-interaction of hIAPP with rat IAPP (rIAPP)鈥攁 non-amyloidogenic peptide with high sequence similarity to hIAPP鈥攎ight influence the aggregation and toxicity of hIAPP. However, the exact role of rIAPP in hIAPP aggregation and toxicity still remains unclear. In this work, we investigated the effect of cross-sequence interactions between full-length hIAPP_1鈥?7 and rIAPP_1鈥?7 on hybrid amyloid structures, aggregation kinetics, and cell toxicity using combined computational and experimental approaches. Experimental results indicate a contrasting role of rIAPP in hIAPP aggregation, in which rIAPP initially inhibits the early aggregation and nuclei formation of hIAPP, but hIAPP seeds can also recruit both hIAPP and rIAPP to form more hybrid fibrils, thus promoting amyloid fibrillation ultimately. The coincubation of hIAPP and rIAPP also decreases cell viability, presumably due to the formation of more toxic hybrid oligomers at the prolonged lag phase. Comparative MD simulations confirm that the cross-sequence interactions between hIAPP and rIAPP stabilize 尾-sheet structure and thus likely promote their fibrillization. This work provides valuable insights into a critical role of cross-amyloid interactions in protein aggregation.