Ribosomal proteins dynamics and its association with actin filaments and
local translation in axonal growth cones of dorsal root ganglia neurons
Abstract
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 (mTOR) complex 1 (mTORC1) signaling in growth cones
of dorsal root ganglion (DRG) 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 (NGF). 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.