Ap2b1, also known as adaptor-related protein complex 2 subunit beta 1, is involved in the endocytosis process, a crucial cellular mechanism for internalizing extracellular materials. It is associated with pathways such as clathrin-mediated endocytosis and caveola-mediated endocytosis, which are vital for maintaining cellular homeostasis, nutrient uptake, and signal transduction [4,5].

In the context of various diseases, in high-altitude cerebral edema, up-regulated nuclear respiratory factor 1 (NRF1) was found to up-regulate Ap2b1 in activated microglia under hypoxia, enhancing phagocytic function and contributing to the development of the disease [1]. In a male mouse model of noise-induced sensorineural hearing loss, miR-145b negatively regulated Ap2b1, and depletion of miR-145b alleviated auditory threshold shifts and outer hair cell loss by upregulating Ap2b1 expression [2]. In Parkinson's disease and related disorders, lower levels of AP2B1 were observed in the cerebrospinal fluid (CSF) of patients compared to healthy controls, suggesting its potential as a biomarker for synaptic dysfunction [3]. Regarding viral infections, LINC08148 knockout downregulated the transcription levels of Ap2b1 among other endocytosis-related genes, reducing the replication of Zika virus [4]. Also, the G protein-coupled receptor FFAR2 was shown to interact with β-arrestin1 which in turn interacted with AP2B1, and knockdown of AP2B1 impaired influenza A virus replication [5]. In Alzheimer's disease, differences in the CSF concentration of AP2B1 were observed between patients and healthy controls, indicating its possible role in the disease's pathogenesis [6,8]. In major depressive disorder, AP2B1 was identified as a hub gene in a protein-protein interaction network, suggesting it could be a potential therapeutic target [7]. In the study of hUC-MSC extracellular vesicles, AP2A1 and AP2B1 may play a role in treating Alzheimer's disease by regulating the synaptic vesicle cycle signalling pathway [9].

In conclusion, Ap2b1 is essential for endocytosis-related cellular functions. Studies using various models, though not always gene-knockout models, have revealed its significance in multiple disease areas including high-altitude cerebral edema, sensorineural hearing loss, neurodegenerative diseases, viral infections, and major depressive disorder. These findings provide insights into potential therapeutic strategies and biomarker development related to these diseases.