NTR domain, Netrin-1-like subfamily; The C-terminal NTR domain of netrins is also called domain C in the context of C. elegans netrin UNC-6. Netrins are secreted proteins that function as tropic cues in the direction of axon growth and cell migration during neural development. These proteins may be chemoattractive to some neurons and chemorepellant for others. In the case of netrin-1, attraction and repulsion responses are mediated by the DCC and UNC-5 receptor families. The biological activities of C. elegans UNC-6, which may either attract or repel migrating cells or axons, are mediated by its different domains. The C-terminal NTR domain of UNC-6 has been shown to inhibit axon branching activity.