In this remarkable process multiple fusion pores open between the outer acrosomal membrane and the overlying plasma membrane, connecting the lumen of the acrosome to the extracellular milieu. Therefore, the fusion pore functions as an effective mechanism to connect intracellular organelles and release vesicle a Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina b Instituto de Investigaciones en Físico-Química de Córdoba (INFIQC) -Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba (UNC), 5016, Córdoba. Argentina c Facultad de Ingeniería, Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina d Instituto de Histología y Embriología de Mendoza (IHEM) -Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina, Tel: +54 261 405 4843; E-mail: diego.masone@ingenieria.uncuyo.edu.ar † Electronic Supplementary Information (ESI) available: simulation repetitions; minimum distance measurements from nearest SMACs to the centre of the fusion pore; correlation between lipid mean squared displacements and SMAC:lipid contacts; plot averaged SMAC:lipid contacts per lipid species; correlation between radius of gyration and SMAC:lipid contacts; measurement of SMAC self-interactions; plots of density charge profiles along Z axis while the fusion pore is open; secondrank order parameter calculations along with tables S1, S2 and S3 listing bonds between beads; table S4 listing details of all simulations performed in this study. See DOI: 00.0000/00000000. contents during exocytosis. Although the nucleation of the fusion pore is thermodynamically unfavourable (and thought to be mediated by specialized proteins), it is widely accepted that once formed the pore can evolve following different paths: rapid dilation, slow expansion, transient flickering (open-close repetitions) and also resealing .