title: Local translation of extranuclear lamin B promotes axon maintenance.
abstract: Local protein synthesis plays a key role in regulating stimulus-induced responses in dendrites and axons. Recent genome-wide studies have revealed that thousands of different transcripts reside in these distal neuronal compartments, but identifying those with functionally significant roles presents a challenge. We performed an unbiased screen to look for stimulus-induced, protein synthesis-dependent changes in the proteome of Xenopus retinal ganglion cell (RGC) axons. The intermediate filament protein lamin B2 (LB2), normally associated with the nuclear membrane, was identified as an unexpected major target. Axonal ribosome immunoprecipitation confirmed translation of lb2 mRNA in vivo. Inhibition of lb2 mRNA translation in axons in vivo does not affect guidance but causes axonal degeneration. Axonal LB2 associates with mitochondria, and LB2-deficient axons exhibit mitochondrial dysfunction and defects in axonal transport. Our results thus suggest that axonally synthesized lamin B plays a crucial role in axon maintenance by promoting mitochondrial function.
authors.affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK.
authors.forename: Byung C
authors.initials: BC
authors.lastname: Yoon
authors.forename: Hosung
authors.initials: H
authors.lastname: Jung
authors.forename: Asha
authors.initials: A
authors.lastname: Dwivedy
authors.forename: Catherine M
authors.initials: CM
authors.lastname: O'Hare
authors.forename: Krishna H
authors.initials: KH
authors.lastname: Zivraj
authors.forename: Christine E
authors.initials: CE
authors.lastname: Holt
mesh_terms: D000818:Animals; D001370:Axonal Transport; D001369:Axons / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D034921:Lamin Type B / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D014176:Protein Biosynthesis; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000378:metabolism
chemical_list: D034921:Lamin Type B