Myosin VI controls localization of golgi satellites at active presynaptic boutons

Abstract

Neurons, as long-lived non-dividing cells with complex morphology, depend on a highly elaborate secretory trafficking system which enables a constant turnover of proteins and membranes. Previously, it was shown that simplified, Golgi-related structures called Golgi satellites (GS) are present in the dendrites of primary hippocampal neurons. These organelles are distinct from the somatic Golgi complex and are involved in de novo glycosylation and local forward trafficking of membrane proteins. However, the question of whether GS are also targeted to the axons of principal neurons remained unanswered. In this study, we investigated the subcellular distribution of GS in adult hippocampal neurons. Our findings showed that GS are present all along the axon, extending to the distal tips of the growth cone. Similar to dendritic GS, the axonal organelles are labeled by the same GS markers and are capable of mature glycosylation. Live imaging experiments revealed the presence of both mobile and immobile GS in the axon, and that the switch between active transport and stalling of GS was modulated by neuronal firing. We found that GS frequently pause at en passant synapses and remain stationary for longer time periods at activated pre-synaptic boutons. This behavior is dependent on the actin cytoskeleton and the actin-based motor protein myosin VI. Overall, our study demonstrates that neuronal activity can dynamically regulate the positioning of GS in the axon, shedding light on the intricate mechanisms underlying organelle trafficking in neurons.