Association of TrkA and APP Is Promoted by NGF and Reduced by Cell Death-Promoting Agents

Abstract

The amyloid precursor protein (APP) interacts with the tropomyosin receptor kinase A (TrkA) in normal rat, mouse, and human brain tissue but not in Alzheimer’s disease (AD) brain tissue. However, it has not been reported whether the two proteins interact directly, and if so, which domains are involved. Clarifying these points will increase our understanding of the role and regulation of the TrkA/APP interaction in normal brain functioning as well as in AD. Here we addressed these questions using bimolecular fluorescence complementation (BiFC) and the proximity ligation assay (PLA). We demonstrated that exogenously expressed APP and TrkA associate through their juxtamembrane/transmembrane domains, to form a complex that localizes mainly to the plasma membrane, endoplasmic reticulum (ER) and Golgi. Formation of the complex was inhibited by p75NTR, ShcC and Mint-2. Importantly, we demonstrated that the association between endogenous APP and TrkA in primary septal neurons were modified by NGF, or by drugs that either inhibit ER-to-Golgi transport or perturb microtubules and microfilaments. Interestingly, several agents that induce cell death [amyloid β (Aβ)-peptide, staurosporine and rapamycin], albeit via different mechanisms, all caused dissociation of APP/TrkA complexes and increased production of C-terminal fragment (β-CTF) APP fragment. These findings open new perspectives for investigating the interplay between these proteins during neurodegeneration and AD.

Lineage-specific differentiation of osteogenic progenitors from pluripotent stem cells reveals the FGF1-RUNX2 association in neural crest-derived osteoprogenitors

“…83 This may play a role in the potential of NCs to give rise to tissues of ectodermal and mesodermal (connective) lineages. 80 When contextualized based on a particular OP's germ layer of origin, transcriptomic patterns meet expectations and further support the notion that OP differentiation remained faithful to lineage type.…”

“…79 Osteoblastsecreted NGF stimulates nerve sprouting, which points to an interesting crosstalk between the skeletal and nervous systems. 80,81 ANTI-SENSE A2 OF PAPPA (PAPPA-AS2) controls the upstream signaling pathway(s) during adipogenesis. 82 Antisense transcripts cause cisrepression of transcription of their sense counterparts, which usually results in a negative correlation between the two transcriptional states.…”

The Medial Septum Is Insulin Resistant in the AD Presymptomatic Phase: Rescue by Nerve Growth Factor-Driven IRS1 Activation

“…Briefly, once MINUS and PLUS PLA probes are in close proximity, the DNA strands interact and the subsequent addition of two other circle-forming DNA oligonucleotides takes place, leading to DNA amplification reaction, detected by Texas red fluorescence. As previously reported [ 38 ], DIV10 cholinergic neurons were fixed in 4% PFA for 15 min and subjected to in situ PLA according to the manufacture’s instruction (Duolink In Situ Detection Reagents Red kit, Sigma Aldrich, DUO92008). To stain the nuclei dried coverslips were mounted with mounting medium (DUO82040).…”

Screening for Host Proteins Interacting with Escherichia Coli O157:H7 EspF using Bimolecular Fluorescence Complementation

“…Studies have demonstrated the advantage of using BiFC to detect protein-protein interactions [64,65]. We noticed that the BiFC technology has at least three advantages that are not found with conventional approaches such as yeast-two-hybrid assays or co-immunoprecipitation (co-IP)/mass spectrometry.…”