Supplemental Data

Files in this Data Supplement:

• Supplemental Figure 1 - Alignment of receptor-like protein kinases with experimentally verified phosphorylation sites. Unambiguously assigned phosphorylation sites are printed in white on red background; candidate sites in black with yellow background if one out of two or more neighboring residues is phosphorylated, or white on brown background if the identified phosphopeptide is not unique to a single protein.
• Supplemental Figure 2 - Acid-, base-, and proline-directed phosphorylation site motifs. The -6 to +6 amino acid sequences of unambiguous phosphorylation sites were sorted with MS Excel sorting functions according to different residues in the -3, -2, -1, +1, and +2 position, and the resulting groups "aligned"/ordered by ClustalW. Because of the constraint that all sequences are aligned at the phosphorylation site, the order reflects only similarity and no true phylogenetic relationship.
• Supplemental Table 1 - Experimentally determined phosphorylation sites in plasma membrane proteins. GenPept and FASTA are online links to the NCBI entry (Sequence Viewer) and the protein sequence in FASTA format of the phosphoprotein; Pepscore is the Mascot score and n_phos the number of phosphorylation sites in the corresponding peptide. Peptide scores above 30 can be considered high confidence; scores between 20 and 30 are ambiguous but the sequence may still be correct. In the pepseq+phos column, phosphorylation sites that have been unambiguously assigned are marked in bold red letters; normal red letters denote potential phosphorylation sites, i.e., one out of two or three red letters is the phosphorylation site.