Implication for the regulation of catabolism drawn from the single insulin-like growth factor binding domain protein (SIBD) gene in the mud crab, Scylla paramamosain.
Insulin-like growth factor (IGF) signaling system holds a central position in regulating growth and metabolism in vertebrates. As critical components of this system, the IGF-binding proteins (IGFBPs) play important roles in regulating the biological activities of IGFs. Recently, the single IGF-binding domain protein (SIBD) was identified in invertebrates and its sequence was highly homologous with the N-terminal domain of IGFBP. In view of the possible role as counterparts of vertebrate IGFBPs, SIBDs have attracted the ever-increasing attention. This study reports the identification of a 1284bp SIBD gene (Sp-SIBD) from a member of commercially important family of Portunidae. The tissue distribution analysis showed that Sp-SIBD was mainly expressed in the nervous tissues and hepatopancreas. RNA in situ hybridization analysis showed that the positive signals were predominantly distributed in the secretory cells of the hepatopancreas. Subsequently, we examined the effects of various stresses, including hyperosmotic stress, hyperthermia, activated stress and fasting, on glucose levels in the hemolymph and Sp-SIBD expressions in the hepatopancreas. Interestingly, we found that Sp-SIBD expression was strongly up-regulated in response to these catabolic circumstances. Given the previous findings of insulin-like peptides (ILPs) in invertebrates, we speculate that invertebrate ILPs and SIBDs promise to serve as a pair of counterparts of IGFs and IGFBPs from vertebrate species respectively. In this context, the combined results suggested, by analogy with IGFBP 1 from vertebrates, for the first time that SIBD might play a key physiological role by sequestering ILPs to inhibit energy-expensive growth until conditions are more favorable.
['Huang|Xiaoshuai|X|', 'Ye|Haihui|H|', 'Huang|Huiyang|H|', 'Liu|An|A|', 'Feng|Biyun|B|']
D000595:Amino Acid Sequence D000818:Animals D060829:Arthropod Proteins D001483:Base Sequence D003386:Brachyura D003001:Cloning, Molecular D004734:Energy Metabolism D005215:Fasting D005334:Fever D005947:Glucose D006458:Hemolymph D043143:Hepatopancreas D017403:In Situ Hybridization D007328:Insulin D018969:Insulin-Like Growth Factor Binding Proteins D008969:Molecular Sequence Data D009997:Osmotic Pressure D010766:Phosphorylation D017386:Sequence Homology, Amino Acid D015398:Signal Transduction D013002:Somatomedins D013312:Stress, Physiological
Scylla paramamosain Insulin-like peptide Glucose metabolism Growth inhibitor Insulin-like growth factor-binding protein