Abstract
ROS-GC1 belongs to the Ca(2+)-modulated sub-family of membrane guanylate cyclases. It primarily exists and is linked with signaling of the sensory neurons - sight, smell, taste, and pinealocytes. Exceptionally, it is also present and is Ca(2+)-modulated in t he non-neuronal cells, the sperm cells in the testes, where S100B protein serves as its Ca(2+) sensor. The present report demonstrates the identification of an additional Ca(2+) sensor of ROS-GC1 in the testes, neurocalcin δ. Through mouse molecular genetic models, it compares and quantifies the relative input of the S100B and neurocalcin δ in regulating the Ca(2+) signaling of ROS-GC1 transduction machinery, and via immunochemistry it demonstrates the co-presence of neurocalcin δ and ROS-GC1 in the spermatogenic cells of the testes. The suggestion is that in more ways than one the Ca(2+)-modulated ROS-GC1 transduction system is linked with the testicular function. This non-neuronal transduction system may represent an illustration of the ROS-GC1 expanding role in the trans-signaling of the neural and non-neural systems.