ACAT1 regulates the dynamics of free cholesterols in plasma membrane which leads to the APP-α-processing alteration.

Abstract

Acyl-CoA:cholesterol acyltransferase 1 (ACAT1) is a key enzyme exclusively using free cholesterols as the substrates in cell and is involved in the cellular cholesterol homeostasis. In this study, we used human neuroblastoma cell line SK-N-SH as a model and first observed that inhibiting ACAT1 can decrease the amyloid precursor protein (APP)-α-processing. Meanwhile, the transfection experiments using the small interfering RNA and expression plasmid of ACAT1 indicated that ACAT1 can dependently affect the APP-α-processing. Furthermore, inhibiting ACAT1 was found to increase the free cholesterols in plasma membrane (PM-FC), and the increased PM-FC caused by inhibiting ACAT1 can lead to the decrease of the APP-α-processing, indicating that ACAT1 regulates the dynamics of PM-FC, which leads to the alteration of the APP-α-processing. More importantly, further results showed that under the ACAT1 inhibition, the alterations of the PM-FC and the subsequent APP-α-processing are not dependent on the cellular total cholesterol level, confirming that ACAT1 regulates the dynamics of PM-FC. Finally, we revealed that even when the Niemann-Pick-Type C-dependent pathway is blocked, the ACAT1 inhibition still obviously results in the PM-FC increase, suggesting that the ACAT1-dependent pathway is responsible for the shuttling of PM-FC to the intracellular pool. Our data provide a novel insight that ACAT1 which enzymatically regulates the dynamics of PM-FC may play important roles in the human neuronal cells.

• Authors: Ming Zhu, Xiaonan Zhao, Jia Chen, Jiajia Xu, Guangjing Hu, Dongqing Guo, Qin Li, Xiaowei Zhang, Catherine C Y Chang, Baoliang Song, Ying Xiong, Tayuan Chang, Boliang Li
• Journal: Acta biochimica et biophysica Sinica (Acta Biochim Biophys Sin (Shanghai)) Vol. 47 Issue 12 Pg. 951-9 (Dec 2015) ISSN: 1745-7270 [Electronic] China
• PMID: 26474739 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author 2015. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

Chemical References

• APP protein, human
• Amyloid beta-Protein Precursor
• RNA, Small Interfering
• Cholesterol
• ACAT1 protein, human
• Acetyl-CoA C-Acetyltransferase

Topics

• Acetyl-CoA C-Acetyltransferase (metabolism)
• Amyloid beta-Protein Precursor (metabolism)
• Cell Line, Tumor
• Cell Membrane (metabolism)
• Cholesterol (metabolism)
• Gene Expression Regulation
• Gene Expression Regulation, Neoplastic
• Humans
• Inflammation
• Plasmids (metabolism)
• RNA Interference
• RNA, Small Interfering (metabolism)