Exploring the multifaceted functions of amyloid precursor protein-like (APPL) in metabolism and memory using Drosophila melanogaster.

Amyloid precursor protein (APP) is a single-pass transmembrane protein abundantly expressed in the central nervous system and implicated in familial Alzheimer's disease (AD), a progressive neurodegenerative disorder that impairs memory. Here, we investigated the role of amyloid precursor protein-like (APPL) using the model organism Drosophila melanogaster. In this study, Appl null mutants exhibited a reduced lifespan under normal conditions and increased triglyceride (TAG) levels, which were mitigated by metformin treatment. Additionally, taste associative memory impairment in Appl^d mutants suggested APPL's role in memory formation, which was restored by curcumin supplementation. The Appl^d mutants also displayed reduced climbing ability, which was improved by supplementation with vitamins C (ascorbic acid) and B₂ (riboflavin). These findings suggest that APPL is involved in metabolic regulation, cognition, climbing activity, and aging in Drosophila melanogaster.