title: A {gamma}-secretase-independent mechanism of signal transduction by the amyloid precursor protein.
abstract: It has been proposed that gamma-secretase-mediated release of the amyloid precursor protein (APP) intracellular domain (AICD) results in nuclear translocation and signaling through a complex with the adaptor protein Fe65 and the histone acetyltransferase Tip60. Here, we show that APP and Fe65 activate transcription through a Gal4-Tip60 reporter in presenilin-1/2-deficient cells lacking generation of AICD. APP and Fe65 also activated transcription in the presence of gamma-secretase inhibitors that prevent amyloid beta-peptide production in human embryonic kidney 293 and SH-SY5Y cells. In contrast to the transcriptionally active Notch intracellular domain, expression of AICD did not activate transcription. An alternative mechanism for APP signal transduction is suggested by the identification of essential cyclin-dependent kinase (CDK) phosphorylation sites in Tip60. Mutation of these Tip60 phosphorylation sites or treatment with the CDK inhibitor roscovitine blocked the ability of APP to signal through Tip60. Moreover, APP stabilized Tip60 through CDK-dependent phosphorylation. Subcellular fractionation and confocal immunofluorescence showed that APP recruited Tip60 to membrane compartments. Thus, APP may signal to the nucleus by a gamma-secretase-independent mechanism that involves membrane sequestration and phosphorylation of Tip60.
authors.affiliation: Department of Neurology and Division of Neuroscience, The Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hass
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Yankner
mesh_terms: D053829:Amyloid Precursor Protein Secretases; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D051548:Histone Acetyltransferases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000378:metabolism; D000074443:Lysine Acetyltransferase 5; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D053764:Presenilin-1; D053766:Presenilin-2; D017434:Protein Structure, Tertiary; D011687:Purines / Q000494:pharmacology; D051880:Receptors, Notch / Q000737:chemistry; D000077546:Roscovitine; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D013347:Subcellular Fractions; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: C091042:APBB1 protein, human; D016564:Amyloid beta-Protein Precursor; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C508853:PSEN1 protein, human; C508861:PSEN2 protein, human; D053764:Presenilin-1; D053766:Presenilin-2; D011687:Purines; D051880:Receptors, Notch; D000077546:Roscovitine; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5; D018844:Cyclin-Dependent Kinases; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse