Phospho-Form Specific Substrates of Protein Kinase B (AKT1)
| Autor: | McShane McKenna, Nileeka Balasuriya, Shanshan Zhong, Shawn Shun-Cheng Li, Patrick O'Donoghue |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Cell signaling Histology kinase lcsh:Biotechnology Biomedical Engineering Bioengineering Peptide 03 medical and health sciences 0302 clinical medicine Solid-phase synthesis GSK-3 lcsh:TP248.13-248.65 phosphoserine tRNASep Protein kinase B Original Research chemistry.chemical_classification AKT1 Kinase Bioengineering and Biotechnology 030104 developmental biology Enzyme genetic code expansion Biochemistry chemistry PDK1 030220 oncology & carcinogenesis embryonic structures Phosphorylation Biotechnology |
| Zdroj: | Frontiers in Bioengineering and Biotechnology Frontiers in Bioengineering and Biotechnology, Vol 8 (2021) |
| ISSN: | 2296-4185 |
| Popis: | Protein kinase B (AKT1) is hyper-activated in diverse human tumors. AKT1 is activated by phosphorylation at two key regulatory sites, Thr308 and Ser473. Active AKT1 phosphorylates many, perhaps hundreds, of downstream cellular targets in the cytosol and nucleus. AKT1 is well-known for phosphorylating proteins that regulate cell survival and apoptosis, however, the full catalog of AKT1 substrates remains unknown. Using peptide arrays, we recently discovered that each phosphorylated form of AKT1 (pAKT1S473, pAKT1T308, and ppAKT1S473,T308) has a distinct substrate specificity, and these data were used to predict potential new AKT1 substrates. To test the high-confidence predictions, we synthesized target peptides representing putative AKT1 substrates. Peptides substrates were synthesized by solid phase synthesis and their purity was confirmed by mass spectrometry. Most of the predicted peptides showed phosphate accepting activity similar to or greater than that observed with a peptide derived from a well-established AKT1 substrate, glycogen synthase kinase 3β (GSK-3β). Among the novel substrates, AKT1 was most active with peptides representing PIP3-binding protein Rab11 family-interacting protein 2 and cysteinyl leukotriene receptor 1, indicating their potential role in AKT1-dependent cellular signaling. The ppAKT1S473,T308 enzyme was highly selective for peptides containing a patch of basic residues at −5, −4, −3 and aromatic residues (Phe/Tyr) at +1 positions from the phosphorylation site. The pAKT1S473 variant preferred more acidic peptides, Ser or Pro at +4, and was agnostic to the residue at −5. The data further support our hypothesis that Ser473 phosphorylation plays a key role in modulating AKT1 substrate selectivity. |
| Databáze: | OpenAIRE |
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