title: SMN and the Gemin proteins form sub-complexes that localise to both stationary and dynamic neurite granules.
abstract: Childhood spinal muscular atrophy (SMA) is caused by a reduction in survival motor neuron (SMN) protein. SMN is expressed in every cell type, but it is predominantly the lower motor neurones of the spinal cord that degenerate in SMA. SMN has been linked to the axonal transport of beta-actin mRNA, a breakdown in which could trigger disease onset. It is known that SMN is present in transport ribonucleoproteins (RNPs) granules that also contain Gemin2 and Gemin3. To further characterise these granules we have performed live cell imaging of GFP-tagged SMN, GFP-Gemin2, GFP-Gemin3, GFP-Gemin6 and GFP-Gemin7. In all, we have made two important observations: (1) SMN granules appear metamorphic; and (2) the SMN-Gemin complex(es) appears to localise to two distinct subsets of bodies in neurites; stationary bodies and smaller dynamic bodies. This study provides an insight into the neuronal function of the SMN complex.
authors.affiliation: Functional Neurobiology, Institute of Biomedical and Clinical Science, Peninsula Medical School, St Luke's Campus, Exeter, UK.
authors.forename: Adrian G
authors.initials: AG
authors.lastname: Todd
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Shaw
authors.forename: Robert
authors.initials: R
authors.lastname: Morse
authors.forename: Howard
authors.initials: H
authors.lastname: Stebbings
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Young
mesh_terms: D045744:Cell Line, Tumor; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D016501:Neurites / Q000378:metabolism*; D055532:SMN Complex Proteins / Q000378:metabolism*; D014897:Spinal Muscular Atrophies of Childhood / Q000378:metabolism; D055533:Survival of Motor Neuron 1 Protein / Q000378:metabolism*; D022161:Transport Vesicles / Q000378:metabolism*
chemical_list: D055532:SMN Complex Proteins; D055533:Survival of Motor Neuron 1 Protein; D049452:Green Fluorescent Proteins