Objective Alzheimer's disease (AD) is one of the major disorders worldwide. Recent research suggests that the amyloid-β precursor protein intracellular domain (AICD) is a potential contributor to AD development and progression. The small AICD is rapidly degraded after processing from the full-length protein. The present study aimed to apply a highly efficient biotinylation approach in vitro to study AICD-associated complexes in neurocytes. Methods By coexpressing Escherichia coli biotin ligase with biotinyl-tagged AICD in the SH-SY5Y neuronal cell line, the effects of AICD overexpression on cell proliferation and apoptosis were analyzed. Besides, AICD-associated nuclear transcriptional complexes were purified and then examined by mass spectrometry. Results Our data showed that AICD overexpression not only affected cell proliferation but also led to apoptosis in differentiated SH-SY5Y cells. Moreover, biotinylation allowed single-step purification of biotinylated AICD-associated complexes from total nuclear extract via high-affinity biotin-streptavidin binding. Following this by mass spectrometry, we identified physically associated proteins, some reported previously and other novel binding partners, CUX1 and SPT5. Conclusion Based on these results, a map of the AICD-associated nuclear interactome was depicted. Specifically, AICD can activate CUX1 transcriptional activity, which may be associated with AICD-dependent neuronal cell death. This work helps to understand the AICD-associated biological events in AD progression and provides novel insights into the development of AD.
Wulin YangAmy Yong Chen LauShuizhong LuoQian ZhuLi Lu
