Backdoor opening in actin. (IMAGE) Max Planck Institute of Molecular Physiology Caption Structural rearrangements insight actin result in movements (green arrows) that lead to the stepwise opening of the backdoor. This allows the release (orange arrows) of the phosphate (orange). Credit MPI of Molecular Physiology Usage Restrictions The image may only be used with appropriate caption or credit. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.