Preprint Article Version 1 This version is not peer-reviewed

Phosphorylation-Dependent Inhibition of Akt1

Version 1 : Received: 20 July 2018 / Approved: 21 July 2018 / Online: 21 July 2018 (12:35:26 CEST)

A peer-reviewed article of this Preprint also exists.

Balasuriya, N.; McKenna, M.; Liu, X.; Li, S.S.C.; O’Donoghue, P. Phosphorylation-Dependent Inhibition of Akt1. Genes 2018, 9, 450. Balasuriya, N.; McKenna, M.; Liu, X.; Li, S.S.C.; O’Donoghue, P. Phosphorylation-Dependent Inhibition of Akt1. Genes 2018, 9, 450.

Journal reference: Genes 2018, 9, 450
DOI: 10.3390/genes9090450

Abstract

Akt1 is a proto-oncogene that is over active in most cancers. Akt1 activation requires phosphorylation at Thr308; phosphorylation at Ser473 further enhances catalytic activity. Akt1 activity is also regulated via interactions between the kinase domain and the N-terminal auto-inhibitory pleckstrin homology (PH) domain. As it was previously difficult to produce Akt1 in site-specifically phosphorylated forms, the contribution of each activating phosphorylation site to auto-inhibition was unknown. Using a combination of genetic code expansion and in vivo enzymatic phosphorylation, we produced Akt1 variants containing programmed phosphorylation to probe the interplay between Akt1 phosphorylation status and the auto-inhibitory function of the PH domain. Deletion of the PH domain increased the enzyme activity for all three phosphorylated Akt1 variants. For the doubly phosphorylated enzyme, deletion of the PH domain relieved auto-inhibition by 295-fold. We next found that phosphorylation at Ser473 provided resistance to chemical inhibition by Akti-1/2 inhibitor VIII. The Akti-1/2 inhibitor was most effective against pAkt1T308 and showed 4-fold decreased potency with Akt1 variants phosphorylated at Ser473. The data highlight the need to design more potent Akt1 inhibitors that are effective against the doubly phosphorylated and most pathogenic form of Akt1.

Subject Areas

genetic code expansion, protein kinase B, phosphoinositide dependent kinase 1 (PDK1), phosphoseryl-tRNA synthetase (SepRS), tRNASep

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.