The calcineurin-dynamin 1 complex as a calcium sensor for synaptic vesicleendocytosis

Exocytosis of synaptic vesicles is calcium-dependent, with synaptotagmin se rving as the calcium sensor. Endocytosis of synaptic vesicles has also been postulated as a calcium-dependent process; however, an endocytic calcium s ensor has not been found. We now report a physical association between the calcium-dependent phosphatase calcineurin and dynamin 1, a component of the synaptic endocytic machinery. The calcineurin-dynamin 1 interaction is cal cium-dependent, with an EC50 for calcium in the range of 0.1-0.4 mu M. Disr uption of the calcineurin-dynamin 1 interaction inhibits clathrin-mediated endocytosis. Thus, the calcium-dependent formation of the calcineurin-dynam in 1 complex, delivered to the other endocytic coat proteins, provides a ca lcium-sensing mechanism that facilitates endocytosis.