Dendritic LSm1/CBP80-mRNPs mark the early steps of transport commitment and translational control.
Messenger RNA (mRNA) transport to neuronal dendrites is crucial for synaptic plasticity, but little is known of assembly or translational regulation of dendritic messenger ribonucleoproteins (mRNPs). Here we characterize a novel mRNP complex that is found in neuronal dendrites throughout the central nervous system and in some axonal processes of the spinal cord. The complex is characterized by the LSm1 protein, which so far has been implicated in mRNA degradation in nonneuronal cells. In brain, it associates with intact mRNAs. Interestingly, the LSm1-mRNPs contain the cap-binding protein CBP80 that associates with (pre)mRNAs in the nucleus, suggesting that the dendritic LSm1 complex has been assembled in the nucleus. In support of this notion, neuronal LSm1 is partially nuclear and inhibition of mRNA synthesis increases its nuclear localization. Importantly, CBP80 is also present in the dendrites and both LSm1 and CBP80 shift significantly into the spines upon stimulation of glutamergic receptors, suggesting that these mRNPs are translationally activated and contribute to the regulated local protein synthesis.
di Penta
Alessandra
A
Laboratory for Neurobiochemistry, Department for Experimental Neurosciences, Fondazione Santa Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, 00143 Rome, Italy.
Mercaldo
Valentina
V
Florenzano
Fulvio
F
Munck
Sebastian
S
Ciotti
M Teresa
MT
Zalfa
Francesca
F
Mercanti
Delio
D
Molinari
Marco
M
Bagni
Claudia
C
Achsel
Tilmann
T
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000166:cytology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D020868:Gene Silencing; D051379:Mice; D008815:Mice, Inbred Strains; D009474:Neurons / Q000166:cytology / Q000502:physiology; D039502:Nuclear Cap-Binding Protein Complex / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology; D039221:mRNA Cleavage and Polyadenylation Factors / Q000378:metabolism
D015415:Biomarkers; C539243:CPEB1 protein, rat; C539242:LSm1 protein, rat; D039502:Nuclear Cap-Binding Protein Complex; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D039221:mRNA Cleavage and Polyadenylation Factors; C026452:messenger ribonucleoprotein; D004722:Endoribonucleases