Phosphorylation-dependent substrate selectivity of protein kinase B (AKT1).
J Biol Chem
; 295(24): 8120-8134, 2020 06 12.
Article
en En
| MEDLINE
| ID: mdl-32350110
ABSTRACT
Protein kinase B (AKT1) is a central node in a signaling pathway that regulates cell survival. The diverse pathways regulated by AKT1 are communicated in the cell via the phosphorylation of perhaps more than 100 cellular substrates. AKT1 is itself activated by phosphorylation at Thr-308 and Ser-473. Despite the fact that these phosphorylation sites are biomarkers for cancers and tumor biology, their individual roles in shaping AKT1 substrate selectivity are unknown. We recently developed a method to produce AKT1 with programmed phosphorylation at either or both of its key regulatory sites. Here, we used both defined and randomized peptide libraries to map the substrate selectivity of site-specific, singly and doubly phosphorylated AKT1 variants. To globally quantitate AKT1 substrate preferences, we synthesized three AKT1 substrate peptide libraries one based on 84 "known" substrates and two independent and larger oriented peptide array libraries (OPALs) of â¼1011 peptides each. We found that each phospho-form of AKT1 has common and distinct substrate requirements. Compared with pAKT1T308, the addition of Ser-473 phosphorylation increased AKT1 activities on some, but not all of its substrates. This is the first report that Ser-473 phosphorylation can positively or negatively regulate kinase activity in a substrate-dependent fashion. Bioinformatics analysis indicated that the OPAL-activity data effectively discriminate known AKT1 substrates from closely related kinase substrates. Our results also enabled predictions of novel AKT1 substrates that suggest new and expanded roles for AKT1 signaling in regulating cellular processes.
Palabras clave
Akt PKB; RNA metabolism; cell signaling; genetic code expansion; oriented peptide array library; peptide array; phosphoinositide-dependent kinase 1; phosphoseryl-tRNA synthetase; post-translational modification (PTM); protein phosphorylation; serine/threonine protein kinase; substrate specificity; tRNASep
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Proteínas Proto-Oncogénicas c-akt
Tipo de estudio:
Clinical_trials
/
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
2020
Tipo del documento:
Article
País de afiliación:
Canadá