Allatostatins

Introduction

Allatostatin (AST) was originally discovered in the corpora allatum of insects and is the largest family of neuropeptides in invertebrates, named for its ability to inhibit the synthesis of the corpora allatum and release juvenile hormone. Thereafter, the neuron having AST immunoreactivity or AST is successively found or isolated in coelenterates, worms, soft armor animals, and crustaceans. According to the biochemical structural features of AST, it can be divided into three categories: (1) A-type AST, which is first isolated in sputum, and its peptide chain has a highly conserved C-terminal structure. this core sequence is the active region necessary for AST to inhibit the synthesis and release of juvenile hormone; (2) B-type AST, whose peptide chain has a highly conserved amidated structure, (3) C-type AST, which is found in manduca. Among all types of ASTs, A-type AST is the most common and C-type is less.

Mechanism of action

The function of AST is determined by its special structure. The sequences of AST can be divided into address regions and information regions. The address region is the N-terminal sequence of the primary structure, which determines the binding of the AST to a particular receptor, thereby affecting the efficacy of the AST. The information region is the homologous region of the C-terminal amino acid, which affects the response of the target tissue to AST during the adaptation to the receptor. The corpora allatum secretes juvenile hormone, which regulates the development and reproduction of insects. It is found that AST produced by brain neuroendocrine cells is responsible for regulating the activity of corpora allatum. In addition, AST has also been found to be involved in the regulation of a range of physiological processes as neurotransmitters.

Application of Allatostatins

Through the understanding of the function of AST, people have applied it as new insecticides, which cause abnormal changes such as endocrine disorders in the insects and kill them. The neuropeptide hormone AST in crustaceans can promote their growth and development, involved in many biological processes like peeling, gonadal maturation and egg formation. The study of crustacean molting and reproductive mechanisms will provide a favorable condition for the crustaceans in aquaculture.

References

1. Stay B, Tobe S S, Bendena W G. Allatostatins: identification, primary structures, functions and distribution.[J]. Advances in Insect Physiology, 1994, 25(08):267-337.
2. Bendena W G, Donly B C, Tobe S S. Allatostatins: A Growing Family of Neuropeptides with Structural and Functional Diversity[J]. Annals of the New York Academy of Sciences, 2010, 897(1):311-329.