Exploring the role of vault complex in the nervous system: a literature review

Vault RNAs (vtRNAs) are a novel group of non-coding RNAs that are involved in various signaling mechanisms. vtRNAs are joined by three proteins major vault protein (MVP), vault poly (ADP-ribose) polymerase (VPARP), and telomerase-associated protein 1 (TEP1) to form the vault complex. In humans, only four vtRNA including vtRNA 1-1, vtRNA 1-2, vtRNA 1-3, vtRNA 2-1) have been discovered. In nerve cells, vtRNA is involved in synapse formation through MAPK signaling. vtRNA travels to the distal area of neurites as a key unit in the vault complex. Moreover, tRNA is detached from the vault complex in the neurite via a mitotic kinase Aurora-A-reliant MVP phosphorylation. Several molecules contribute to the formation of vtRNAs. For instance, SRSF2 and NSUN2 and their attachment to vtRNA1-1 determines the production of small-vtRNAs. Through the same factors, vtRNAs could play a role in neurodevelopmental deficits. Addition the role of vtRNA expression and vault proteins has been recently studied in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) as well as brain cancers. While the mechanisms of vtRNA involvement in neurological disorders is not well-demonstrated, we believe this could be related to the impact of vtRNA regulation in autophagy, immunoregulation, RNA stability, cellular stress, apoptosis, and regulation of other epigenetic pathways. The present review captures the state-of-the-art regarding the role of vtRNAs in neurodevelopment, normal nervous system function, and neurological disorders.