Teneurins: A conserved family of transmembrane proteins involved in intercellular signaling during development

Teneurins, which were initially described as ten-a and the pair-rule gene ten-m/odz in Drosophila, are a family of highly conserved proteins that have recently been characterized in Caenorhabditis elegans and a number of vertebrates. We have proposed the nomenclature teneurin 1–4 for the four members of this gene family found in vertebrates. Recent evidence shows that teneurins belong to a novel class of signaling molecules that function both at the cell surface as type II transmembrane receptors and, after the release of the intracellular domain, as transcriptional regulators. Nuclear localization of the intracellular domain has been observed in vitro in mammalian cells and confirmed in vivo in C. elegans. RNAi studies and mutational analysis has revealed that Ten-1 in C. elegans is an important regulator of many aspects of morphogenesis, including germ cell development and neuronal pathfinding. In vertebrates, teneurins are concentrated in the developing and adult central nervous system and at sites of pattern formation, including the developing limb. Teneurins also possess a carboxy terminal sequence that may be processed to generate a neuromodulatory peptide. Teneurin function appears to be required for a fundamentally important signaling mechanism conserved between invertebrates and vertebrates having an impact on many processes relying on cell–cell contact throughout development.