Proposed model for the mechanism underlying VGLUT subtype regulation of release probability.

(A) VGLUT2 cannot bind endophilin, thus VGLUT2-containing vesicles have high endophilin levels and high vesicle release probability (Pvr).

(B) Because VGLUT1 binds endophilin, VGLUT1-containing vesicles have lower levels of endophilin and therefore low Pvr.

(C) Overexpression of endophilin overwhelmsthe available VGLUT1 binding sites for endophilin, resulting in higher levels of endophilin and higher Pvr.

(D) Knockdown of endophilin reduces the amount of endophilin and lowers Pvr.