Nuclear localization of amyloid-β precursor protein-binding protein Fe65 is dependent on regulated intramembrane proteolysis

Koistinen, Niina; Edlund, Anna; Menon, Preeti; Ivanova, Elena V.; Bacanu, Silviu‐Alin; Iverfeldt, Kerstin

doi:10.1371/journal.pone.0173888

Cited by 8 publications

(6 citation statements)

References 41 publications

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“…To investigate the role of APP–Ser-675 phosphorylation on APP processing, a previously described APP 695 -myc cDNA construct (APPwt) (22) was mutated at Ser-675 to either alanine (APP-S675A) or glutamic acid (APP-S675E) to mimic nonphosphorylated and phosphorylated forms of the Ser-675 residue, respectively. Human neuroblastoma SK-N-AS cells were transfected with the different APP constructs and after treatment with the γ-secretase inhibitor DAPT, the full-length APP, sAPPα, and APP-CTF levels were analyzed.…”

Section: Resultsmentioning

confidence: 99%

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Phosphorylation of the amyloid precursor protein (APP) at Ser-675 promotes APP processing involving meprin β

Menon

Koistinen

Iverfeldt³

et al. 2019

Journal of Biological Chemistry

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Alzheimer's disease (AD) is a neurodegenerative disorder characterized by abnormal deposition of β-amyloid (Aβ) peptides. Aβ is a cleavage product of the amyloid precursor protein (APP), and aberrant posttranslational modifications of APP can alter APP processing and increase Aβ generation. In the AD brain, seven different residues, including Ser-675 (APP695 numbering) in the APP cytoplasmic domain has been found to be phosphorylated. Here, we show that expression of a phosphomimetic variant of Ser-675 in APP (APP-S675E), in human neuroblastoma SK-N-AS cells, reduces secretion of the soluble APP ectodomain (sAPPα), even though the total plasma membrane level of APP was unchanged compared with APP levels in cells expressing APPwt or APP-S675A. Moreover, the level of an alternative larger C-terminal fragment (CTF) increased in the APP-S675E cells, whereas the CTF form that was most abundant in cells expressing APPwt or APP-S675A decreased in the APP-S675E cells. Upon siRNA-mediated knockdown of the astacin metalloprotease meprin β, the levels of the alternative CTF decreased and the CTF ratio was restored back to APPwt levels. Our findings suggest that APP–Ser-675 phosphorylation alters the balance of APP processing, increasing meprin β–mediated and decreasing α-secretase–mediated processing of APP at the plasma membrane. As meprin β cleavage of APP has been shown to result in formation of highly aggregation-prone, truncated Aβ2–40/42 peptides, enhanced APP processing by this enzyme could contribute to AD pathology. We propose that it would be of interest to clarify in future studies how APP–Ser-675 phosphorylation promotes meprin β–mediated APP cleavage.

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Section: Resultsmentioning

confidence: 99%

“…The previously described pcDNA3.1 expression vector containing human APP 695 -myc (APP) was used (22). APP-S675A and APP-S675E were generated using the QuikChange II Site-Directed Mutagenesis Kit (Agilent Technologies) according to the manufacturer's protocol.…”

Section: Methodsmentioning

confidence: 99%

Phosphorylation of the amyloid precursor protein (APP) at Ser-675 promotes APP processing involving meprin β

Menon

Koistinen

Iverfeldt³

et al. 2019

Journal of Biological Chemistry

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“…Upon ε-cleavage of APP by γ-secretase, the AICD is released from the membrane into the cytosol and the Fe65-AICD complex translocates to the nucleus. Very recent results indicate that the PTB2 rather than the WW domain is important for the nuclear localization of Fe65 (Koistinen et al, 2017 ). Secretase cleavage is influenced by various aspects like APP cellular localization (Haass et al, 2012 ), APP dimerization (Winkler et al, 2015 ) and APP and Fe65 phosphorylation (Bukhari et al, 2016 ).…”

Section: Discussionmentioning

confidence: 99%

Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction

Feilen

Haubrich

Strecker

et al. 2017

Front. Mol. Neurosci.

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Physiological function and pathology of the Alzheimer’s disease causing amyloid precursor protein (APP) are correlated with its cytosolic adaptor Fe65 encompassing a WW and two phosphotyrosine-binding domains (PTBs). The C-terminal Fe65-PTB2 binds a large portion of the APP intracellular domain (AICD) including the GYENPTY internalization sequence fingerprint. AICD binding to Fe65-PTB2 opens an intra-molecular interaction causing a structural change and altering Fe65 activity. Here we show that in the absence of the AICD, Fe65-PTB2 forms a homodimer in solution and determine its crystal structure at 2.6 Å resolution. Dimerization involves the unwinding of a C-terminal α-helix that mimics binding of the AICD internalization sequence, thus shielding the hydrophobic binding pocket. Specific dimer formation is validated by nuclear magnetic resonance (NMR) techniques and cell-based analyses reveal that Fe65-PTB2 together with the WW domain are necessary and sufficient for dimerization. Together, our data demonstrate that Fe65 dimerizes via its APP interaction site, suggesting that besides intra- also intermolecular interactions between Fe65 molecules contribute to homeostatic regulation of APP mediated signaling.

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“…Certain proteins that are widely studied for their role in NDs are prion, tau, β-amyloid, α-synuclein, and Huntington ( Gitler et al, 2017 ). It is implicated that misfolding of these proteins leads to their aggregation in the neuronal cells resulting in neurodegeneration ( Ross and Poirier, 2004 ; Santa-Mara et al, 2008 ; Goebel, 2009 ; Spears et al, 2014 ; Koistinen et al, 2017 ). However, the role of cytoskeletal protein actin in the manifestation of NDs have been far from understood.…”

Section: Introductionmentioning

confidence: 99%

Ofloxacin as a Disruptor of Actin Aggresome “Hirano Bodies”: A Potential Repurposed Drug for the Treatment of Neurodegenerative Diseases

Pathak

Parkar

Tripathi

et al. 2020

Front. Aging Neurosci.

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There is a growing number of aging populations that are more prone to the prevalence of neuropathological disorders. Two major diseases that show a late onset of the symptoms include Alzheimer’s disorder (AD) and Parkinson’s disorder (PD), which are causing an unexpected social and economic impact on the families. A large number of researches in the last decade have focused upon the role of amyloid precursor protein, Aβ-plaque, and intraneuronal neurofibrillary tangles (tau-proteins). However, there is very few understanding of actin-associated paracrystalline structures formed in the hippocampus region of the brain and are called Hirano bodies. These actin-rich inclusion bodies are known to modulate the synaptic plasticity and employ conspicuous effects on long-term potentiation and paired-pulse paradigms. Since the currently known drugs have very little effect in controlling the progression of these diseases, there is a need to develop therapeutic agents, which can have improved efficacy and bioavailability, and can transport across the blood–brain barrier. Moreover, finding novel targets involving compound screening is both laborious and is an expensive process in itself followed by equally tedious Food and Drug Administration (FDA) approval exercise. Finding alternative functions to the already existing FDA-approved molecules for reversing the progression of age-related proteinopathies is of utmost importance. In the current study, we decipher the role of a broad-spectrum general antibiotic (Ofloxacin) on actin polymerization dynamics using various biophysical techniques like right-angle light scattering, dynamic light scattering, circular dichroism spectrometry, isothermal titration calorimetry, scanning electron microscopy, etc. We have also performed in silico docking studies to deduce a plausible mechanism of the drug binding to the actin. We report that actin gets disrupted upon binding to Ofloxacin in a concentration-dependent manner. We have inferred that Ofloxacin, when attached to a drug delivery system, can act as a good candidate for the treatment of neuropathological diseases.

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Nuclear localization of amyloid-β precursor protein-binding protein Fe65 is dependent on regulated intramembrane proteolysis

Cited by 8 publications

References 41 publications

Phosphorylation of the amyloid precursor protein (APP) at Ser-675 promotes APP processing involving meprin β

Phosphorylation of the amyloid precursor protein (APP) at Ser-675 promotes APP processing involving meprin β

Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction

Ofloxacin as a Disruptor of Actin Aggresome “Hirano Bodies”: A Potential Repurposed Drug for the Treatment of Neurodegenerative Diseases

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