MK2 nonenzymatically promotes nuclear translocation of caspase-3 and resultant apoptosis

Othello Del Rosario, Karthik Suresh, Medha Kallem, Gayatri Singh, Anika Shah, Linda Zheng, Xin Yun, Nicolas M. Philip, Nirupama Putcha, Marni B. McClure, Haiyang Jiang, Franco D'Alessio, Meera Srivastava, Alakesh Bera, Larissa A. Shimoda, Michael Merchant, Madhavi J. Rane, Carolyn E. Machamer, Jason Mock, Robert HaganAbigail L. Koch, Naresh M. Punjabi, Todd M. Kolb, Mahendra Damarla

Research output: Contribution to journalArticlepeer-review

Abstract

We have previously identified mitogen-activated protein kinase-activated protein kinase 2 (MK2) is required for caspase-3 nuclear translocation in the execution of apoptosis; however, little is known of the underlying mechanisms. Therefore, we sought to determine the role of kinase and nonkinase functions of MK2 in promoting nuclear translocation of caspase-3. We identified two non-small cell lung cancer cell lines for use in these experiments based on low MK2 expression. Wild-type, enzymatic and cellular localization mutant MK2 constructs were expressed using adenoviral infection. Cell death was evaluated by flow cytometry. In addition, cell lysates were harvested for protein analyses. Phosphorylation of caspase-3 was determined using two-dimensional gel electrophoresis followed by immunoblotting and in vitro kinase assay. Association between MK2 and caspase-3 was evaluated using proximity-based biotin ligation assays and co-immunoprecipitation. Overexpression of MK2 resulted in nuclear translocation of caspase-3 and caspase-3-mediated apoptosis. MK2 directly phosphorylates caspase-3; however, phosphorylation status of caspase-3 or MK2-dependent phosphorylation of caspase-3 did not alter caspase-3 activity. The enzymatic function of MK2 was dispensable in nuclear translocation of caspase-3. MK2 and caspase-3 associated together and a nonenzymatic function of MK2, chaperoned nuclear trafficking, is required for caspase-3-mediated apoptosis. Taken together, our results demonstrate a nonenzymatic role for MK2 in the nuclear translocation of caspase-3. Furthermore, MK2 may function as a molecular switch in regulating the transition between the cytosolic and nuclear functions of caspase-3.

Original languageEnglish (US)
Pages (from-to)L700-L711
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume324
Issue number5
DOIs
StatePublished - May 2023

Keywords

  • MAPKAPK2
  • apoptosis
  • caspase-3
  • kinases
  • nuclear translocation

ASJC Scopus subject areas

  • Physiology (medical)
  • Physiology
  • Pulmonary and Respiratory Medicine
  • Cell Biology

Fingerprint

Dive into the research topics of 'MK2 nonenzymatically promotes nuclear translocation of caspase-3 and resultant apoptosis'. Together they form a unique fingerprint.

Cite this