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.
College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
Xiaoshuai
X
Huang
College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; Collaborative Innovation Center for Development and Utilization of Marine Biological Resources, Xiamen 361102, China. Electronic address: haihuiye@xmu.edu.cn.
Haihui
H
Ye
College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
Huiyang
H
Huang
College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
An
A
Liu
College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
Biyun
B
Feng
D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003386:Brachyura / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003001:Cloning, Molecular; D004734:Energy Metabolism; D005215:Fasting / Q000502:physiology; D005334:Fever; D005947:Glucose / Q000378:metabolism; D006458:Hemolymph / Q000378:metabolism*; D043143:Hepatopancreas / Q000378:metabolism*; D017403:In Situ Hybridization; D007328:Insulin / Q000378:metabolism*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D010766:Phosphorylation; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013002:Somatomedins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological
D060829:Arthropod Proteins; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D005947:Glucose
Glucose metabolism; Growth inhibitor; Insulin-like growth factor-binding protein; Insulin-like peptide; Scylla paramamosain