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Defining the role of cytoskeletal components in the formation of apoptopodia and apoptotic bodies during apoptosis

  • Sarah Caruso
  • Georgia K. Atkin-Smith
  • Amy A. Baxter
  • Rochelle Tixeria
  • Lanzhou Jiang
  • Dilara C. Ozkocak
  • Jascinta P. Santavanond
  • Mark D. Hulett
  • Peter Lock
  • Thanh Kha Phan
  • Ivan K. H. PoonEmail author


During apoptosis, dying cells undergo dynamic morphological changes that ultimately lead to their disassembly into fragments called apoptotic bodies (ApoBDs). Reorganisation of the cytoskeletal structures is key in driving various apoptotic morphologies, including the loss of cell adhesion and membrane bleb formation. However, whether cytoskeletal components are also involved in morphological changes that occur later during apoptosis, such as the recently described generation of thin apoptotic membrane protrusions called apoptopodia and subsequent ApoBD formation, is not well defined. Through monitoring the progression of apoptosis by confocal microscopy, specifically focusing on the apoptopodia formation step, we characterised the presence of F-actin and microtubules in a subset of apoptopodia generated by T cells and monocytes. Interestingly, targeting actin polymerisation and microtubule assembly pharmacologically had no major effect on apoptopodia formation. These data demonstrate apoptopodia as a novel type of membrane protrusion that could be formed in the absence of actin polymerisation and microtubule assembly.


Apoptotic bodies Apoptotic cell disassembly Apoptotic morphology Apoptopodia Cytoskeletal components Membrane protrusions 



We thank the La Trobe BioImaging Platform for access to microscopy and flow cytometry equipment and assistance with microscopy. We thank Dr Hendrika Duivenvoorden for her assistance with 3D cultures. This work was supported by grants from the National Health & Medical Research Council of Australia (GNT1141732, GNT1125033, GNT1140187), Australian Research Council (DP170103790) and La Trobe University (RFA2018).

Author contributions

SC, GKAS and IKHP designed and performed experiments with assistance from co-authors. AB generated and performed experiments on vimentin deficient cells. SC, GKAS and IKHP wrote the manuscript with input from co-authors.

Compliance with ethical standards

Competing interests

The authors declare no competing financial interests.

Supplementary material

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Sarah Caruso
    • 1
  • Georgia K. Atkin-Smith
    • 1
  • Amy A. Baxter
    • 1
  • Rochelle Tixeria
    • 1
  • Lanzhou Jiang
    • 1
  • Dilara C. Ozkocak
    • 1
  • Jascinta P. Santavanond
    • 1
  • Mark D. Hulett
    • 1
  • Peter Lock
    • 1
  • Thanh Kha Phan
    • 1
  • Ivan K. H. Poon
    • 1
    Email author
  1. 1.Department of Biochemistry and Genetics, La Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneAustralia

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