Two cis-acting elements in the 3′ untranslated region of α-CaMKII regulate its dendritic targeting

Dendritic localization of the α subunit of Ca 2+ /calmodulin-dependent protein kinase II (αCaMKII) mRNA in CNS neurons requires its 3′ untranslated region (3′UTR). We investigated this targeting mechanism by identifying two cis-acting elements in the 3′UTR. One is a 30-nucleotide element that mediated dendritic translocation. A homologous sequence in the 3′UTR of neurogranin, transcripts of which also reside in dendrites, also funtioned in cis to promote its dendritic transport. Other putative elements in the αCaMKII mRNA inhibit its transport in a resting state. This inhibition was removed in depolarized neurons, and such activity-dependent derepression was a primary requirement for their dendritic targeting.