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Phosphorylation regulates the activity of the SMN complex during assembly of spliceosomal U snRNPs.
- Source :
-
EMBO reports [EMBO Rep] 2005 Jan; Vol. 6 (1), pp. 70-6. - Publication Year :
- 2005
-
Abstract
- The assembly of spliceosomal U-rich small nuclear ribonucleoproteins (U snRNPs) is an ATP-dependent process mediated by the coordinated action of the SMN and the PRMT5 complex. Here, we provide evidence that the activity of this assembly machinery is regulated by means of post-translational modification. We show that two main components of the SMN/PRMT5 system, namely the survival motor neuron (SMN) protein (reduced levels thereof causing spinal muscular atrophy) and pICln, are phosphorylated in vivo. Both proteins share a previously unknown motif containing either one or two phosphoserines. Alteration of these residues in SMN (serines 28 and 31) significantly impairs the activity of the SMN complex. Despite the presence of SMN in both the nucleus and cytoplasm, we find that only the latter promotes efficient SMN-mediated U snRNP assembly activity. As cytoplasmic SMN is phosphorylated to a much larger extent, we hypothesize that this modification is a key activator of the SMN complex.
- Subjects :
- Amino Acid Sequence
Cyclic AMP Response Element-Binding Protein chemistry
Cyclic AMP Response Element-Binding Protein genetics
HeLa Cells
Humans
Molecular Sequence Data
Multiprotein Complexes chemistry
Multiprotein Complexes metabolism
Nerve Tissue Proteins chemistry
Nerve Tissue Proteins genetics
Phosphorylation
Protein Binding
Protein Methyltransferases metabolism
Protein-Arginine N-Methyltransferases
RNA-Binding Proteins chemistry
RNA-Binding Proteins genetics
SMN Complex Proteins
Sequence Alignment
Cyclic AMP Response Element-Binding Protein metabolism
Nerve Tissue Proteins metabolism
RNA-Binding Proteins metabolism
Ribonucleoproteins, Small Nuclear metabolism
Spliceosomes metabolism
Uridine metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1469-221X
- Volume :
- 6
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- EMBO reports
- Publication Type :
- Academic Journal
- Accession number :
- 15592453
- Full Text :
- https://doi.org/10.1038/sj.embor.7400301