Among translationSuch decoding results in the assembly of RNP com-plexes which in turn are propelled along cytoskeletalelements by molecular motors. The dendritic location of translational machinery andthe active transport of specific RNAs to dendritic desti-nation sites are indicative that proteins are locallysynthesized in dendrites. This concept iswell supportedby experimental evidence, and mechanisms of localtranslational control are being investigated.
Dendritic proteins may be locally synthesized inresponse to various synaptic activations. Activationof glutamate receptors appears to regulate dendritictranslation. Blockade of N-methyl-D-aspartate receptor NMDAR activation with antago-nist 3- 2 carboxypiperazin-4yl propylphosphonicacid prevents the increase in CaMKIIa protein levelsin synaptic fractions from dark-reared, light-exposedanimals. Synaptic stimulation by neurotrophins such as.
Local proteinsynthesis is required for neurotrophin-induced synap-tic plasticity in CA1 dendritic regions. Translational control mechanisms that have beenimplicated in local synaptic regulation can broadlybe categorized into three groups: mechanisms thattarget the initiation step, those that target the elonga-tion step, and those that operate at the RNA level. We discuss each category in turn Figure 1.
The combined datasuggest coordination between these two pathwaysand raise the possibility of multilevel translationalregulation in dendrites.
Work with Drosophila has shown that eIF4E. Translation initiation factor PABP interacts with. Cytoplasmic polyadenylation is another transla-tional control mechanism that may operate at thesynapse. As was first reported with Xenopus oocytes,some mRNAs have short poly A tails and remaintranslationally dormant; translation is activated onlysubsequent to their cytoplasmic polyadenylation. Polyadenylation is initiated through phosphorylation. Figure 1 Schematic illustration of translational control pathways in de RNA transport and local control of translation. Annual Review4E-BP.
Pof CPEB by the kinase aurora. In addition, factors involvedin the polyadenylation mechanism, such as aurora,CPEB, poly A polymerase, but not maskin, havebeen identified at neuronal synapses. Translation elongation Elongation may also bethe target of local translational control in neurons. Overall pro-tein synthesis is reduced upon phosphorylation ofeEF2, although individual neuronal mRNAs maybe differentially receptive to such elongation con-trol. FMRP has also been suggested to regulate trans-lation at the level of elongation.
UnphosphorylatedFMRP is associated with actively translating poly-ribosomes, whereas a fraction of phosphorylatedFMRP is associated with translationally inactivepolyribosomes. Elongation factors can be targets of regulation as. Applica-tion of rapamycin blocks this effect, indicating thatthe previously discussed mTOR pathway is involvedin this regulation.
The expression of eEF1A has alsobeen shown to be increased after DHPG-inducedLTD or after induction of LTP by high-frequencystimulation of the perforant path; however, only theformer appears to be sensitive to protein synthesisinhibitors. Fuster - Mnemonic and predictive functions of cortical neurons in a memory task. Fuster - Brain systems have a way of reconciling "opposite" views of neural processing; the motor system is no exception. Open peer commentary to "Do cortical and basal ganglia motor areas use 'motor programs' to control movement?
Alexander et al. Behavioral and Brain Sciences 15 , Fuster - Memory cells in primate cortex and the activation of memory networks. Ono, L. Squire, M. Raichle, D. Perrett and M. Fukuda Eds. Fuster - Spatial and temporal factors in the role of prefrontal and parietal cortex in visuo-motor integration.
Cerebral Cortex 3 , Zipser, B. Kehoe, G. Littlewort and J. Fuster - A spiking model of short-term active memory.
Journal of Neuroscience 13 : , Fuster - Frontal lobes. Current Opinion in Neurobiology 3 : , Fuster and C. Tresguerres Ed. Fuster - Cognitive correlates of complex temporal patterns of firing. Boussaid, M. Brissaud, G. Ritschard, J-P Royet Eds. Shindy, K.
Fuster - Reversible deficit in haptic delay tasks from cooling prefrontal cortex. Cerebral Cortex 4 , Swartz, E. Halgren, F. Simpkins, J. Fuster, M. Mandelkern, T. Kristadumkorn, M. Gee, C.
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Brown, J. Ropchan and W.
NeuroReport 5 , Fuster - La physiologie frontale et le cycle perception-action. Revue de Neuropsychologie 4 , Fuster - Call it what it is: Motor memory.
Open peer commentary to "The representing brain: Neural correlates of motor intention and imagery" by M. Behavioral and Brain Sciences 17 , Fuster - In search of the engrammer. Open peer commentary to "Hippocampus and Memory", by H. Eichenbaum et al. Halgren, J.
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Fuster, F. Simpkins, M. Gee, and M. Mandelkern - Cortical metabolic activation in humans during a visual memory task. Fuster - Memory and planning: Two temporal perspectives of frontal lobe function.
Jasper, S. Riggio and P. Goldman-Rakic Eds. Fuster - Frontal cortex and the cognitive support of behavior. McGaugh, F. Fuster - Memory in the cortex of the primate. Biological Research 28 , Fuster - Temporal processing. Grafman, K. Holyoak and F.