MRCKa is activated by caspase cleavage to assemble an apical actin ring for epithelial cell extrusion

Extrusion of apoptotic cells from epithelial tissues requires orchestrated morphological rearrangements of the apoptotic cell and its neighbors. However, the connections between the apoptotic cascade and events leading to extrusion are not fully understood. Here, we characterize an apoptotic extrusi...

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Published inThe Journal of cell biology Vol. 217; no. 1; p. 231
Main Authors Gagliardi, Paolo Armando, Somale, Desiana, Puliafito, Alberto, Chiaverina, Giulia, di Blasio, Laura, Oneto, Michele, Bianchini, Paolo, Bussolino, Federico, Primo, Luca
Format Journal Article
LanguageEnglish
Published New York Rockefeller University Press 01.01.2018
Subjects
Actin
Actomyosin
Apoptosis
Bundles
Caspase
Cdc42 protein
Cell body
Cleavage
Contraction
Cytoskeleton
Dystrophy
Epithelial cells
Extrusion
Kinases
Myosin
Myotonic dystrophy
Polymerization
Signal transduction
Signaling
Tissues
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Summary:Extrusion of apoptotic cells from epithelial tissues requires orchestrated morphological rearrangements of the apoptotic cell and its neighbors. However, the connections between the apoptotic cascade and events leading to extrusion are not fully understood. Here, we characterize an apoptotic extrusion apical actin ring (EAAR) that is assembled within the apoptotic cell and drives epithelial extrusion. Caspase-mediated cleavage of myotonic dystrophy kinase-related CDC42-binding kinase-a (MRCKa) triggers a signaling pathway that leads to the assembly of EAAR that pulls actin bundles, resulting in the compaction and removal of the cell body. We provide a detailed portrait of the EAAR including F-actin flow, the contribution of myosin contraction, and actin polymerization at bundles' terminals when the product of MRCKa cleavage is expressed. These results add to our understanding of the mechanisms controlling the process of epithelial extrusion by establishing a causal relationship between the triggering events of apoptosis, the activation of MRCKa, and its subsequent effects on the dynamics of actomyosin cytoskeleton rearrangement.
ISSN:0021-9525
1540-8140