Mutant larvae barely move.

Mutant synapses lack normally shaped T-bars and the number of membrane-proximal synaptic vesicles (counted over the whole active zone) is reduced compared to wild type.

The evoked excitatory junctional current (eEJC) is almost abolished at the larval neuromuscular junction (NMJ). The frequency and amplitude of miniature EJCs (mEJCs) is normal at the mutant NMJ. Quantal content is thus dramatically reduced. Under elevated extracellular calcium conditions, the eEJC amplitude is reduced to approximately 10% of control levels. eEJC rise times are slightly but significantly increased, while mEJC rise times are normal.

At paired-pulse stimulation, mutant synapses show an unusually strong facilitation. When stimulated with five consecutive pulses at 100Hz, mutant eEJCs exhibit substantial recovery and almost reach absolute control levels on the fifth pulse. Together this suggests that the mutant suffers from a severely reduced release probability.