Nuclear signaling by the APP intracellular domain occurs predominantly through the amyloidogenic processing pathway.
Proteolytic processing of the amyloid precursor protein (APP) occurs via two alternative pathways, localized to different subcellular compartments, which result in functionally distinct outcomes. Cleavage by a beta-gamma sequence generates the Abeta peptide that plays a central role in Alzheimer's disease. In the case of alpha-gamma cleavage, a secreted neurotrophic molecule is generated and the Abeta peptide cleaved and destroyed. In both cases, a cytosolic APP intracellular domain (AICD) is generated. We have previously shown that coexpression of APP with the APP-binding protein Fe65 and the histone acetyltransferase Tip60 results in the formation of nuclear complexes (termed AFT complexes), which localize to transcription sites. We now show that blocking endocytosis or the pharmacological or genetic inhibition of the endosomal beta-cleavage pathway reduces translocation of AICD to these nuclear AFT complexes. AICD signaling further depends on active transport along microtubules and can be modulated by interference with both anterograde and retrograde transport systems. Nuclear signaling by endogenous AICD in primary neurons could similarly be blocked by inhibiting beta-cleavage but not by alpha-cleavage inhibition. This suggests that amyloidogenic cleavage, despite representing the minor cleavage pathway of APP, is predominantly responsible for AICD-mediated nuclear signaling.
Psychiatry Research, University of Zurich, August-Forel Strasse 1, 8008 Zurich, Switzerland.
Zoë V
ZV
Goodger
Lawrence
L
Rajendran
Annette
A
Trutzel
Bernhard M
BM
Kohli
Roger M
RM
Nitsch
Uwe
U
Konietzko
D021581:Active Transport, Cell Nucleus; D000682:Amyloid / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D055786:Gene Knockout Techniques; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D015398:Signal Transduction
D000682:Amyloid; D016564:Amyloid beta-Protein Precursor; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse