Posttranslational myristoylation of caspase-activated p21-activated protein kinase 2 (PAK2) potentiates late apoptotic events.

Gonzalo L Vilas, Maria M Corvi, Greg J Plummer, Andrea M Seime, Gareth R Lambkin, Luc G Berthiaume

Proceedings of the National Academy of Sciences of the United States of America 2006 Apr 25

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p21-activated protein kinase (PAK) 2 is a small GTPase-activated serine/threonine kinase regulating various cytoskeletal functions and is cleaved by caspase-3 during apoptosis. We demonstrate that the caspase-cleaved PAK2 C-terminal kinase fragment (C-t-PAK2) is posttranslationally myristoylated, although myristoylation is typically a cotranslational process. Myristoylation and an adjacent polybasic domain of C-t-PAK2 are sufficient to redirect EGFP from the cytosol to membrane ruffles and internal membranes. Membrane localization and the ability of C-t-PAK2 to induce cell death are significantly reduced when myristoylation is abolished. In addition, the proper myristoylation-dependent membrane localization of C-t-PAK2 significantly increased signaling through the stress-activated c-Jun N-terminal kinase signaling pathway, which often regulates apoptosis. Interestingly, C-t-PAK2 promoted cell death without compromising mitochondrial integrity. Posttranslational myristoylation of caspase-cleaved proteins involved in cytoskeletal dynamics (e.g., PAK2, actin, and gelsolin) might be part of a unique series of mechanisms involved in the regulation of the later events of apoptosis.

Citation

Gonzalo L Vilas, Maria M Corvi, Greg J Plummer, Andrea M Seime, Gareth R Lambkin, Luc G Berthiaume. Posttranslational myristoylation of caspase-activated p21-activated protein kinase 2 (PAK2) potentiates late apoptotic events. Proceedings of the National Academy of Sciences of the United States of America. 2006 Apr 25;103(17):6542-7