C-terminal src kinase (CSK)-mediated phosphorylation of eukaryotic elongation factor 2 (EEF2) promotes proteolytic cleavage and nuclear translocation of EEF2

Abstract

Background: The C-terminal Src kinase (Csk) is known as a tumor suppressor, but Src-independent function is unclear. Results: eEF2 is a new protein substrate of Csk. Conclusion: eEF2 phosphorylation and SUMOylation promote its proteolytic cleavage and nuclear localization. Significance: Our findings suggest that a tyrosine kinase can be both a tumor suppressor and a promoter through regulation of different substrate proteins. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.