Axon guidance molecules structure

STRUCTURES OF AXON GUIDANCE MOLECULES AND THEIR NEURONAL RECEPTORS... 

No single cellular axon guidance cue appears to be unique to a particular invertebrate group or class of neuron and hence one cannot a priori exclude any specific cellular structure as the site of axon guidance molecules. Therefore, the cellular identity of guidance factors needs to be established anew every time one begins to work with a new system. 

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