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Updated: Jun 25, 2026
07:55
Imaging the Intracellular Trafficking of APP with Photoactivatable GFP
Published on: October 17, 2015
Trans-dimerization of Amyloid Precursor Protein Family Members Induces Pre- and Postsynaptic Differentiation through
Ritu Rajender1, Natalie Foth1, Simone Eggert1,2
1Department of Human Biology and Human Genetics, RPTU University Kaiserslautern-Landau, Kaiserslautern 67663, Germany.
Summary
All amyloid precursor protein (APP) family members promote synapse formation by acting as synaptic adhesion molecules. Distinct signaling pathways mediate presynaptic and postsynaptic differentiation, offering insights into Alzheimer's disease pathology.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Amyloid precursor protein (APP) and its homologues (APLP1, APLP2) are synaptic adhesion molecules (SAMs) involved in Alzheimer's disease (AD) pathology.
- These proteins localize to synapses, form trans-cellular dimers, and induce presynaptic differentiation.
Purpose of the Study:
- To investigate the role of all APP family members in inducing both pre- and postsynaptic differentiation.
- To elucidate the signaling pathways and molecular mechanisms underlying APP-mediated synaptogenesis.
Main Methods:
- Expression of APP family members in non-neuronal cells and primary mouse neurons.
- Mutagenesis studies involving the E1 domain of APP.
- Pharmacological inhibition of signaling pathways (MAPK, PI3K/Akt).
- Analysis of conditional triple knockout (cTKO) neurons lacking APP family members.
Main Results:
- APP family members induce postsynaptic differentiation in primary neurons, similar to other SAMs.
- Synaptogenic activity is modulated by the E1 domain and soluble APP (sAPP) generation.
- APP-induced differentiation requires intact microtubule/actin cytoskeleton and MAPK pathway.
- PI3K/Akt pathway selectively impairs postsynaptic differentiation, while c-Jun N-terminal kinase is involved in both pre- and postsynaptic differentiation.
- Synaptogenic activity is dependent on postsynaptic APP family members or their interaction partners.
Conclusions:
- All APP family members function as SAMs in trans-synaptic signaling, influencing both presynaptic and postsynaptic differentiation.
- Distinct signaling pathways regulate pre- and postsynaptic differentiation, with Akt specifically required for postsynaptic development.
- APP-mediated synaptogenesis relies on trans-cellular interactions rather than secreted forms.
- These findings provide crucial insights into the physiological roles of APP/APLPs and AD-related synaptopathies.
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