A structural analysis of cytoskeleton components during the execution phase of apoptosis

During the execution phase of apoptosis, the cell undergoes a set of morphological changes which reveal the activation of a complex machinery leading the cell to its disruption into small, spherical, membrane-bounded fragments called apoptotic bodies. In the present study, we have focused on the implications of the microfilament network in the early stages of the active phase of apoptosis. By using confocal microscopy, we have analysed the location of the actin microfilaments and two actin-binding proteins, alpha-actinin and myosin, in F9 embryonal carcinoma cells undergoing apoptosis during the stages previous to their fragmentation. Our results show that these proteins locate in the centre of the disrupting cell and form a three-dimensional structure which suggests the existence of a fully functional contractile system involved in the fragmentation of the cell and the formation of apoptotic bodies.