Transcription Factor NF-κB Is Transported to the Nucleus via Cytoplasmic Dynein/Dynactin Motor Complex in Hippocampal Neurons

Mikenberg I, Widera D, Kaus A, Kaltschmidt B, Kaltschmidt C. Transcription Factor NF-kappa B Is Transported to the Nucleus via Cytoplasmic Dynein/Dynactin Motor Complex in Hippocampal Neurons. PLOS ONE. 2007;2(7):e589.Background. Long-term changes in synaptic plasticity require gene transcription, indicating that signals generated at the synapse must be transported to the nucleus. Synaptic activation of hippocampal neurons is known to trigger retrograde transport of transcription factor NF-kappa B. Transcription factors of the NF-kappa B family are widely expressed in the nervous system and regulate expression of several genes involved in neuroplasticity, cell survival, learning and memory. Principal Findings. In this study, we examine the role of the dynein/dynactin motor complex in the cellular mechanism targeting and transporting activated NF-kappa B to the nucleus in response to synaptic stimulation. We demonstrate that overexpression of dynamitin, which is known to dissociate dynein from microtubules, and treatment with microtubule-disrupting drugs inhibits nuclear accumulation of NF-kappa B p65 and reduces NF-kappa B-dependent transcription activity. In this line, we show that p65 is associated with components of the dynein/dynactin complex in vivo and in vitro and that the nuclear localization sequence (NLS) within NF-kappa B p65 is essential for this binding. Conclusion. This study shows the molecular mechanism for the retrograde transport of activated NF-kappa B from distant synaptic sites towards the nucleus

Chemical tuning of electroluminescent copolymers to improve emission efficiencies and allow patterning

ONE advantage of using conjugated polymers in semiconductor applications is that they can be processed using techniques well established for conventional polymers. We reported recently that poly(p-phenylenevinylene) could be used as the active layer in a light-emitting diode 1, producing yellow/green emission. We have now found that related copolymers, comprising a combination of different arylene units, can be chemically tuned to provide a range of materials with considerably improved properties for this and other applications. By incorporating two different leaving groups into a precursor copolymer, we can selectively eliminate one of these, to give a conjugated/non-conjugated copolymer, or both, to give a fully conjugated copolymer. This allows us to induce local variations in the pi-pi* electronic energy gap at both the molecular and supramolecular level. Variations at the molecular level can act to trap excitons, hindering their migration to quenching sites, and we find that these materials give strongly enhanced quantum yields for electroluminescence (by a factor of up to 30). They also allow control of the colour of emission. Variations at the supramolecular level, by patterning the films to control the progress of conversion, allow the production of structures suitable for multicolour displays. The ability to pattern the film also allows for fabrication of optical waveguides, as regions with different energy gaps have different refractive indices.</p

Huntingtin coordinates the dynein-mediated dynamic positioning of endosomes and lysosomes

We investigated the role of the membrane-associated scaffolding protein huntingtin (Htt) in the dynein-mediated transport of early, recycling, and late endosomes and lysosomes. Our observations support a model of Htt as a facilitator of dynein-mediated trafficking that can regulate the cytoskeletal association of dynamic organelles