has start location has start location signal transduction presynapse presynaptic signal transduction GO:0098928 biological_process Signal transduction in which the initial step occurs in a presynapse. Do not directly annotate. This term intended for grouping. Annotate to either a subclass or to some other subclass of signal transduction extended with has_start_location/occurs_in presynapse or one of its parts. Such extensions will result in automatic annotation to this term. presynaptic signaling pathway