Analysis of SMN-neurite granules: Core Cajal body components are absent from SMN-cytoplasmic complexes.
Childhood spinal muscular atrophy (SMA) is caused by a reduction in survival motor neuron (SMN) protein. SMN is a ubiquitously expressed house keeping protein that is involved in RNA production and processing. However, although SMN is expressed in every cell type, only the lower motor neurons of the spinal cord are degraded in SMA. It remains unclear why this is the case. Recently, SMN has been linked to the axonal transport of beta-actin mRNA from the cell body down to the growth cones. beta-Actin is transported actively in neurite granules (NGs). However, it remains unclear which known SMN-binding partners are present in these SMN-NGs. To address this we have analysed SMN-NGs in a human neuronal cell line, SH-SY5Y, using antibodies against the majority of reported SMN-binding partners, including: Gemin2, Gemin3, Gemin4, Gemin5, Gemin6, Gemin7, Sm core proteins, fibrillarin, EWS, PFNII, Unrip and ZPR1. The obtained results highlight the metamorphic nature of the SMN complex, suggesting that not all the "core" SMN-binding proteins are transported in SMN-NGs.
Clinical Neurobiology, Institute of Biomedical and Clinical Science, Peninsula Medical School, St. Luke's Campus, Exeter, United Kingdom.
Adrian G
AG
Todd
Robert
R
Morse
Debra J
DJ
Shaw
Howard
H
Stebbings
Philip J
PJ
Young
D002675:Child, Preschool; D020541:Coiled Bodies / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D009134:Muscular Atrophy, Spinal / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism*; D021381:Protein Transport; D055532:SMN Complex Proteins / Q000378:metabolism*; D022161:Transport Vesicles / Q000378:metabolism*
D055532:SMN Complex Proteins