Recombinant neural protein PrP can bind with both recombinant and native apolipoprotein E in vitro.
The most essential and crucial step during the pathogenesis of transmissible spongiform encephalopathy is the conformational change of cellular prion protein (PrP(C)) to pathologic isoform (PrP(Sc)). A lot of data revealed that caveolae-like domains (CLDs) in the cell surface were the probable place where the conversion of PrP proteins happened. Apolipoprotein E (ApoE) is an apolipoprotein which is considered to play an important role in the development of Alzheimer's disease and other neurodegenerative diseases by forming protein complex through binding to the receptor located in the clathrin-coated pits of the cell surface. In this study, a 914-bp cDNA sequence encoding human ApoE3 was amplified from neuroblastoma cell line SH-SY5Y. Three human ApoE isomers were expressed and purified from Escherichia coli. ApoE-specific antiserum was prepared by immunizing rabbits with the purified ApoE3. GST/His pull-down assay, immunoprecipitation and ELISA revealed that three full-length ApoE isomers interact with the recombinant full-length PrP protein in vitro. The regions corresponding to protein binding were mapped in the N-terminal segment of ApoE (amino acid 1-194) and the N-terminal of PrP (amino acid 23-90). Moreover, the recombinant PrP showed the ability to form a complex with the native ApoE from liver tissues. Our data provided direct evidence of molecular interaction between ApoE and PrP. It also supplied scientific clues for assessing the significance of CLDs on the surface of cellular membrane in the process of conformational conversion from PrP(C) to PrP(Sc) and probing into the pathogenesis of transmissible spongiform encephalopathy.
Gao
Chen
C
State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China.
Lei
Yan-Jun
YJ
Han
Jun
J
Shi
Qi
Q
Chen
Lan
L
Guo
Yan
Y
Gao
Yong-Jun
YJ
Chen
Jian-Ming
JM
Jiang
Hui-Ying
HY
Zhou
Wei
W
Dong
Xiao-Ping
XP
D001057:Apolipoproteins E / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D002460:Cell Line; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009474:Neurons / Q000378:metabolism*; D018621:PrPC Proteins / Q000737:chemistry* / Q000235:genetics; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry
D001057:Apolipoproteins E; D018621:PrPC Proteins; D011994:Recombinant Proteins