Progress in functions and underlying signal transduction mechanisms of neuropeptides and their receptors in the silkworm Bombyx mori

As a class of neuronal signal molecules, neuropeptides are secreted by the neurosecretory cells and play an important role during the communications of different cells. The specific receptor molecules, which are located on the cell surface, are responsible for the localization of neuropeptide molecules and the activation of corresponding intracellular messengers, and eventually trigger a series of cascade reactions. Neuropeptides also have crucial effects on the growth and development of insects, and regulate almost all life activities. As a model species of the Lepidoptera, the silkworm (Bombyx mori) is an important research model for insect development and physiology. Following the completion of the silkworm genome sequencing, more and more neuropeptides and their receptors in this moth have been identified. They were found to deeply influence lots of physiological activities, such as the growth and development, feeding and digestion, molting, diapause, reproduction and cocooning. In this article, we review