The structural basis of Akt PH domain interaction with calmodulin

Jackson Weako, Hyunbum Jang, Ozlem Keskin, Ruth Nussinov*, Attila Gursoy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Akt plays a key role in the Ras/PI3K/Akt/mTOR signaling pathway. In breast cancer, Akt translocation to the plasma membrane is enabled by the interaction of its pleckstrin homology domain (PHD) with calmodulin (CaM). At the membrane, the conformational change promoted by PIP3 releases CaM and facilitates Thr308 and Ser473 phosphorylation and activation. Here, using modeling and molecular dynamics simulations, we aim to figure out how CaM interacts with Akt's PHD at the atomic level. Our simulations show that CaM-PHD interaction is thermodynamically stable and involves a β-strand rather than an α-helix, in agreement with NMR data, and that electrostatic and hydrophobic interactions are critical. The PHD interacts with CaM lobes; however, multiple modes are possible. IP4, the polar head of PIP3, weakens the CaM-PHD interaction, implicating the release mechanism at the plasma membrane. Recently, we unraveled the mechanism of PI3Kα activation at the atomistic level and the structural basis for Ras role in the activation. Here, our atomistic structural data clarify the mechanism of how CaM interacts, delivers, and releases Akt—the next node in the Ras/PI3K pathway—at the plasma membrane.

Original languageEnglish
Pages (from-to)1994-2008
Number of pages15
JournalBiophysical Journal
Issue number10
StatePublished - 18 May 2021


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