The critical role of the C-terminal lobe of calmodulin in activating eukaryotic elongation factor 2 kinase.

ABSTRACT: Eukaryotic elongation factor 2 kinase (eEF-2K), a member of the α-kinase family, modulates translational rates by phosphorylating eEF-2, a GTPase that facilitates the translocation of the nascent chain on the ribosome during the elongation phase of protein synthesis. eEF-2K is regulated by diverse cellular cues, many of which sensitize it to the Ca²⁺-effector protein calmodulin (CaM). CaM, which binds and allosterically activates eEF-2K in the presence of Ca²⁺, contains two structural "lobes," each with a pair of Ca²⁺-binding EF hands. Using kinetic analysis, we demonstrate that the isolated C-terminal lobe of CaM (CaM_C) is sufficient to engage and fully activate eEF-2K in a Ca²⁺-dependent fashion. Genetically fusing CaM_C to

SUBMITTER: Long KJ 

PROVIDER: S-EPMC12509998 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature