Fig. 7. Proposed role of actin depolymerization in resealing. (a) A cortical barrier to vesicle movement consisting, in part, of filamentous actin is present in undisturbed cells. (b) A plasma membrane disruption allows entry of Ca²⁺ that promotes consequent Ca²⁺-induced actin depolymerization locally in peri-disruption cortex. (c) This facilitates Ca²⁺-induced membrane fusion events required for resealing by removing an obstacle to vesicle-vesicle and vesicle-membrane interaction. (d) Actin polymerization occurring in wounded and other cells lining injury sites many minutes after PMD events may be required for successful restitution or repair of monolayer injury.