title: Microtubule association of a neuronal RNA-binding protein HuD through its binding to the light chain of MAP1B.
abstract: RNA-binding proteins (RBPs) play a vital role in the post-transcriptional regulation of gene expression during neuronal differentiation and synaptic plasticity. One such RBP family, the neuronal Hu protein family, serves as an early marker of neuronal differentiation and targets several mRNAs containing adenine/uridine-rich elements. Recently, we reported that one of the neuronal Hu proteins, HuD stimulates cap-dependent translation through interactions with eIF4A and poly (A) tail. Nevertheless, little is known with respect to how neuronal Hu proteins contribute to the local translation of target mRNAs in neuronal differentiation. Here, we found that neuronal Hu proteins, but not the ubiquitously expressed HuR protein, directly interact with the light chain of microtubule-associated proteins MAP1B (LC1). We also show that HuD simultaneously binds both RNA and LC1 in vitro and that it tightly associates with microtubules in cells in an LC1-dependent manner, raising the possibility that HuD recruits target mRNAs to microtubules. These results uncover the neuronal binding partners for neuron-specific Hu proteins and suggest the involvement of Hu proteins in microtubule-mediated regulation of mRNA expression within neuronal processes.
authors.affiliation: Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kasashima
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Saito
authors.forename: Miho
authors.initials: M
authors.lastname: Fukuda
authors.forename: Akira
authors.initials: A
authors.lastname: Fukao
authors.forename: Yumi
authors.initials: Y
authors.lastname: Sasano
authors.forename: Kunio
authors.initials: K
authors.lastname: Inoue
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakamoto
mesh_terms: D000818:Animals; D051959:ELAV Proteins / Q000378:metabolism*; D000067779:ELAV-Like Protein 4; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D016716:PC12 Cells; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D020798:Two-Hybrid System Techniques
chemical_list: D051959:ELAV Proteins; D000067779:ELAV-Like Protein 4; C498011:Elavl4 protein, mouse; D008869:Microtubule-Associated Proteins; D016601:RNA-Binding Proteins; C085284:microtubule-associated protein 1B; D012313:RNA