Transport to the CNS inhibitory interneurons begins with the B-chain mediating the neurospecific binding of TeNT to the nerve terminal membrane. It binds to GT1b polysialogangliosides, similarly to the "C. botulinum" neurotoxin. It also binds to another poorly characterized GPI-anchored protein receptor more specific to TeNT. Both the ganglioside and the GPI-anchored protein are located in lipid microdomains and both are requisite for specific TeNT binding. Once it is bound, the neurotoxin is then endocytosed into the nerve and begins to travel through the axon to the spinal neurons. The next step, transcytosis from the axon into the CNS inhibitory interneuron, is one of the least understood parts of TeNT action. At least two pathways are involved, one that relies on the recycling of synaptic vesicle 2 (SV2) system and one that does not.