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The intestinal fatty acid binding protein (FABP) is a small protein expressed along the small intestine that bind long-chain fatty acids and other hydrophobic ligands. Several lines of evidence suggest that, once in the nucleus, it interacts with nuclear receptors, activating them and thus transferring the bound ligand into the nucleus. Previous work by our group suggests that FABP2 would participate in the cytoplasm-nucleus translocation of fatty acids. Because the consensus NLS is absent in the sequence of FABP2, we propose that a 3D signal could be responsible for its nuclear translocation. The results obtained by transfection assays of recombinant wild type and mutated forms of Danio rerio Fabp2 in Caco-2 cell cultures, showed that lysine 17, arginine 29 and lysine 30 residues, which are located in the helix-turn-helix region, would constitute a functional non-classical three-dimensional NLS. [ABSTRACT FROM AUTHOR]

Transference of RNAs and ribosomes from Schwann cell-to-axon was demonstrated in normal and regenerating peripheral nerves. Previously, we have shown that RNAs transfer is dependent on F-actin cytoskeleton and Myosin Va. Here, we explored the contribution of microtubules to newly synthesized RNAs transport from Schwann cell nuclei up to nodal microvilli in sciatic nerves. Results using immunohistochemistry and quantitative confocal FRET analysis indicate that Schwann cell-derived RNAs co-localize with microtubules in Schwann cell cytoplasm. Additionally, transport of Schwann cell-derived RNAs is nocodazole and colchicine sensitive demonstrating its dependence on microtubule network integrity. Moreover, mRNAs codifying neuron-specific proteins are among Schwann cell newly synthesized RNAs population, and some of them are associated with KIF1B and KIF5B microtubules-based motors. [ABSTRACT FROM AUTHOR]

: To better understand the role of protein synthesis in axons, we have identified the source of a portion of axonal RNA. We show that proximal segments of transected sciatic nerves accumulate newly-synthesized RNA in axons. This RNA is synthesized in Schwann cells because the RNA was labeled in the complete absence of neuronal cell bodies both in vitro and in vivo. We also demonstrate that the transfer is prevented by disruption of actin and that it fails to occur in the absence of myosin-Va. Our results demonstrate cell-to-cell transfer of RNA and identify part of the mechanism required for transfer. The induction of cell-to-cell RNA transfer by injury suggests that interventions following injury or degeneration, particularly gene therapy, may be accomplished by applying them to nearby glial cells (or implanted stem cells) at the site of injury to promote regeneration. [ABSTRACT FROM AUTHOR]