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bioRxiv · 10.1101/2025.06.27.661901

AP-3 complex sorts preferential cargo to govern dense core vesicle function in neuroendocrine cells

Saxena, S.·Ghosh, V.·Mukherjee, C.·Chauhan, B. S.·BANERJEE, S.·Sahu, B. S.
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Abstract

This study reveals new insights into the role of the Adaptor protein (AP-3) complex in dense core vesicle function. Despite numerous studies, an existing knowledge lacuna in the role of AP-3 in DCV function prompted us to delve deeper. Advanced microscopy and biochemical analysis revealed compromised DCV exocytosis in AP-3-depleted PC12 cells and C. elegans. AP-3 depletion altered the size and positioning of DCVs. Golgi defects and RUSH (Retention under Selective Hook) substantiated the role of AP-3 in trans-Golgi DCV budding. Proteomics revealed the loss of specific known and putative novel DCV proteins, which were mislocalized and rerouted to lysosomes in AP-3-depleted cells. Bioinformatics, Proximity ligation assays and Co-immunoprecipitation identified interactions of mislocalized proteins with AP-3 subunit. These findings corroborated with functional defects in granule maturation, release modes, Zinc and neurotransmitter mobilisation. Our study highlights the complexity of the AP-3 complex in regulating DCV function and its importance in vesicle transport in neurons and neuroendocrine cells. SummaryThis work reveals the critical role of AP-3 complex in DCV function, highlighting its impact on DCV exocytosis, positioning, and trans-Golgi budding. This study identifies Dlk1 as a novel DCV cargo.

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Saxena, S., Ghosh, V., Mukherjee, C., Chauhan, B. S., BANERJEE, S., Sahu, B. S.. 2025-07-01. AP-3 complex sorts preferential cargo to govern dense core vesicle function in neuroendocrine cells. https://doi.org/10.1101/2025.06.27.661901

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