Ribosomal protein dynamics and its association with actin filaments and local translation in axonal growth cones of dorsal root ganglia neurons

Local translation in growth cones plays a critical role in responses to extracellular stimuli, such as axon guidance cues. We previously showed that brain-derived neurotrophic factor (BDNF) activates translation and enhances novel protein synthesis through the activation of mammalian target of rapamycin complex 1 signaling in growth cones of dorsal root ganglion neurons. In this study, we focused on ribosomal protein S6 (RPS6), ribosomal protein P0/1/2 (RPP0/1/2), and actin filaments to determine how localization of ribosomal proteins changes with overall protein synthesis induced by BDNF and nerve growth factor. Our quantitative analysis using immunocytochemistry and super-resolution microscopy indicated that RPS6, RPP0/1/2, and actin tend to colocalize in the absence of stimulation, and that these ribosomal proteins tend to dissociate from actin when local protein synthesis is promoted. We propose that this is because the ribosome is turned into an actively translating ribosome (polysome) by the protein synthesis machinery. This study further clarifies the role of cytoskeletal components in local translation and will inform the study of neurological disorders associated with cytoskeletal disruption.