Table 1. The Target Peptide(s), Corresponding Internal Standards and Selected Transitions For Monitoring Protein Components of the Wnt/beta-Catenin Signaling Pathway.
Residues underlined in bold font indicate the sites of incorporation of stable isotope labels or single amino acid replacements (e.g. alanine to glycine). Roman numerals link to the corresponding peptide signals in Figure 1.
| Assay Development | ||||
|---|---|---|---|---|
| Protein | Target Peptide | Label/Modification | Transitions | Additional Monitored Peptides |
| E-cadherin | VTEPLDR (II) | L5: 13C6, 15N | y3 - y6 | NTGVISVVTTGLDR (I) GLDARPEVTR (III) |
| α-catenin | SDALNSAIDK (III) | A7→G | y4 - y8 | NTSDVISAAK (I) DVDGLDR (II) VVEDGILK IV) IAEQVASFQEEK (V) NAGNEQDLGIQYK (VI) LVYDGIR (VII) |
| β-catenin |
EGLLAIFK (IX) AIPELTK (II) |
E1→D L5: 13C6, 15N |
y2 - y5 y3 - y6 |
HQEAEMAQNAVR (I) LLNDEDQVVVNK (III) SGGIPALVK (IV) VAAGVLCELAQDK (V) LHYGLPVVVK (VI) LLWTTSR (VII) LVQLLVR (VIII) NEGVATYAAAVLFR (X) |
| c-Src | LLLNAENPR (IV) | P8: 13C5, 15N | y4 - y7 | EVLDQVER (I) GPSAAFAPAAAEPK (II) TETDLSFK (III) LFGGFNSSDTVTSPQR (V) WTAPEAALYGR (VI) GSLLDFLK (VII) |
| Axin1 | LLLETAAPR (II) | P8: 13C5, 15N | y3 - y8 | EQVEAEATR (I) SDIYLEYTR (III) SASTEVPGASEDAEK (IV) |
| APC protein | YSDEQLNSGR (I) | G9→A | y3 - y9 | TPPPPPQTAQTK (II) ESTGYLEELEK (III) HVDQPIDYSLK (IV) YATDIPSSQK (V) QNQLHPSSAQSR (VI) |
| GSK3β | QTLPVIYVK (II) | V8: 13C5, 15N | y3 - y8 | LLEYTPTAR (I) |
| PP2A catalytic subunit α/β | YSFLQFDPAPR (III) | P10: 13C5, 15N | y4 - y7 | QLSESQVK (I)* GGWGISPR (II) |
| PP2A 65 kDa regulatory subunit A α | AVGPEITK (I) | A1→G | y3 - y6 | VLELDNVK (II) EWAHATIIPK (III) |
| PP2A 65 kDa regulatory subunit A β | VLELDSVK (I) | V7: 13C5, 15N | y3 - y7 | FGTEWAQNTIVPK (II) LASGDWFTSR (III) |
| PP2A 55 kDa regulatory subunit B α | ILHTAWHPK (I) | P8: 13C5, 15N | y3 - y7 | DITLEASR (II) NAAQFLLSTNDK (III) INLWHLEITDR (IV) |
| Casein kinase I | LFLIDFGLAK (II) | A9→G | y3 - y8 | HPQLLYESK (I) AEFIVGGK (III) ILQGGVGIPHIR (IV) |
| Casein kinase II α | QLYQTLTDYDIR (III) | D10→E | y3 - y10 | YNIELDPR (I) VYTDVNTHRPR (II) |
| Casein kinase II α′ | VLGTEELYGYLK (II) | L11: 13C6, 15N | y3 - y10 | VYAEVNSLR (I) |
| Casein kinase II β | FNLTGLNEQVPHYR (II) | G5→A | y3 - y10 | RPANQFVPR (I) |
| CD44 | FAGVFHVEK (II) | V7: 13C5, 15N | y3 - y8 | LVINSGNGAVEDR (I) YGFIEGHVVIPR (III) |
| Cyclin D1 | FLSLEPVK (I) | V7: 13C5, 15N | y3 - y7 | |
| MMP-7 | DLPHITVDR (I) | V7: 13C5, 15N | y4 - y7 | FYLYDSETK (II) |
| Cortactin | ANFENLAK (VI) | L6: 13C6, 15N | y3 - y7 | YGVQADR (I) FGVQTDR and FGVQSER (II) FGVEQDR (III) TVPVEAVTSK (IV) ENVFQEHQTLK (V) VDQSAVGFEYQGK (VII) LPSSPVYEDAASFK (VIII) YGLFPANYVELR (IX) |
| Axin2 | STETVDSGYR (II) | G8→A | y4 - y8 | ANGQVSLPHFPR (I) NEDGLGEPEGR (III) |
| c-Myc | DQIPELENNEK (I) | E5→D | y6 - y9 | SSDTEENVK (II) |
| TCF7(TCF1) | LPEPLEDGLK (I) | L9: 13C6, 15N | y3 - y9 | |
*
Sequence QLSESQVK (I) is unique to PP2A catalytic subunit α.