Fe65 does not stabilize AICD during activation of transcription in a luciferase assay.
The APP intracellular domain (AICD) could be involved in signaling via interaction with the adaptor protein Fe65, and with the histone acetyl transferase Tip60. However, the real function of AICD and Fe65 in regulation of transcription remains controversial. In this study, the human APPGal4 fusion protein was expressed in CHO cells and the transcriptional activity of AICDGal4 was measured in a luciferase-based reporter assay. AICDGal4 was stabilized by expression of Fe65 and levels of AICDGal4 controlled luciferase activity. On the contrary, when human APP was expressed in CHO cells, coexpression of Fe65 increased luciferase activity without affecting the amount of AICD fragment. AICD produced from APP was protected from degradation by orthophenanthroline, but not by lactacystine, indicating that AICD is not a substrate of the chymotryptic activity of the proteasome. It is concluded that Fe65 can control luciferase activity without stabilizing the labile AICD fragment.
Huysseune
Sandra
S
Université Catholique de Louvain, Center for Neurosciences, Laboratoire de Pharmacologie (FARL 5410), Avenue Hippocrate 54, B-1200 Brussels, Belgium.
Kienlen-Campard
Pascal
P
Octave
Jean-Noël
JN
D016564:Amyloid beta-Protein Precursor / Q000737:chemistry* / Q000235:genetics*; D000818:Animals; D001681:Biological Assay; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D008156:Luciferases / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics*; D010618:Phenanthrolines / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013379:Substrate Specificity / Q000187:drug effects; D013816:Thermodynamics; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics*
D016564:Amyloid beta-Protein Precursor; D009687:Nuclear Proteins; D010446:Peptide Fragments; D010618:Phenanthrolines; D011993:Recombinant Fusion Proteins; C093598:amyloid beta-protein precursor 695 (681-695); D008156:Luciferases; D046988:Proteasome Endopeptidase Complex; C025205:1,10-phenanthroline