Cytoskeleton Rearrangements during the Execution Phase of Apoptosis

Abstract

Apoptosis is a regulated energy-dependent process for the elimination of unnecessary or damaged cells during embryonic development, tissue homeostasis and many pathological conditions. Apoptosis is characterized by specific morphological and biochemical features in which caspase activation has a pivotal role. During apoptosis, cells undergo characteristic morphological reorganizations in which the cytoskeleton participates actively. Traditionally, this cytoskeleton rearrangement has been assigned mainly to actinomyosin ring contraction, with microtubule and intermediate filaments both reported to be depolymerized at early stages of apoptosis. However, recent results have shown that microtubules are reformed during the execution phase of apoptosis forming an apoptotic microtubule network (AMN). Current hypothesis proposes that AMN is required to maintain plasma membrane integrity and cell morphology during the execution phase of apoptosis. AMN disruption provokes apoptotic cell collapse, secondary necrosis and the subsequent release of toxic molecules which can damage surrounding cells and promote inflammation. Therefore, AMN formation in physiological or pathological apoptosis is essential for tissue homeostasis.

AFM Analysis Enables Differentiation between Apoptosis, Necroptosis, and Ferroptosis in Murine Cancer Cells

“…Furthermore, when comparing the elasticity dynamics in different modes of RCD, clear differences could be distinguished ( Figure 3 B). Most likely the fast decrease in elasticity of cells undergoing apoptosis can be explained through an active reorganization and depolymerization of the cytoskeleton by protein activation/inhibition during apoptosis (such as MLCK, ROCKs, executioner caspases), as was previously shown ( Doncel et al., 2017 ; Oropesa-Ávila et al., 2017 ). In this work, it has been suggested that, owing to the absence of any active reorganization in both necroptosis and ferroptosis, the elasticity decrease is more gradual.…”

Eugenol Induces Apoptosis in Tongue Squamous Carcinoma Cells by Mediating the Expression of Bcl-2 Family

“…The blue fluorescence of DAPI permits the visualization of nuclear fragments and condensed nuclei, with the advantages of using it being DNA selectivity and enhanced cell permeability [ 20 ]. Moreover, the cell’s cytoskeleton is formed of actin filaments, microtubules, and intermediate filaments, constituents which are important to ensure cell motility, plasma integrity, characteristic cell morphology, and for allowing cellular transport [ 37 ]. However, one of the hallmarks of cancer is exactly the increased motility of cells, which allows the invasion of adjacent healthy tissues and metastasis [ 38 ].…”

Bio-Field Array: The Influence of Junction Mediating and Regulatory Protein Expression on Cytoskeletal Filament Behavior During Apoptosis in Triple-Negative Breast Cancer

“…19 The BFA dc DEP-EMF’s influence on diamagnetic anisotropy via membrane potential, chloride ion channel modulation and significantly increased transcription (Figure 4) 14 may possibly offer more available ATP (G-Actin/ATP complexes—thereby increasing critical concentrations high enough to affect both the plus and minus end of the actin [unbranched] filaments and subsequent reorganization/elongation of microtubules) to be used by the cell and facilitate cytoskeletal reorganizations (round apoptotic microtubule spikes) for the round apoptosis in these MDA-MB-231 cells (Figure 1). 20…”