Putative phosphorylation sites in SMN. Peptide sequences from human, rat, and mouse SMN were aligned using the ClustalW program. The PhosphoMotif Finder and NetPhosK servers were used to predict serine, threonine, and tyrosine phosphorylation sites in SMN and corresponding kinases for these sites. Putative sites for PKA are highlighted in red, while non-PKA sites are highlighted in grey. Those non-PKA sites that are conserved in all three species, corresponding kinases and kinase motifs, and NetPhosK scores for these sites are listed in Table 1. The three phosphopeptides identified by mass analysis in this study are underlined, and the detected PKA sites are marked by stars.