Dynamics of biosynthesis and release of crustacean hyperglycemic hormone isoforms in the X-organ-sinus gland complex of the crayfish Orconectes limosus.
The crustacean hyperglycemic hormone (CHH) is the major neuropeptide produced by the X-organ-sinus gland neurosecretory system of the crayfish, Orconectes limosus. This hormone is synthesized by two different cell types, as two isomers (CHH and D-Phe3-CHH) which display different activities The aim of this report is to analyze and compare the synthetic and secretory activities of these specialized cells. In vitro pulse-chase incubations and time-course experiments were conducted on isolated X-organ-sinus gland (XO-SG) complexes, followed by analysis of the labeled peptides. The different steps of the post-translational processing of the CHH precursor, including proteolytic cleavage of the propeptide, C-terminal amidation and N-terminal pyroglutamylation were characterized and the kinetics of CHHs maturation were estimated in the different parts of the neuroendocrine complex. Furthermore, synthesis of CHHs in XO-SG complexes and release in incubation media were investigated using combined HPLC/immunoassay. Under basal conditions, i.e. without stimulation, similar dynamics for both isomers were found and results indicate that newly synthesized CHHs are preferentially released.
Ollivaux
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Laboratoire Signaux Endocrines et Toxines d'Invertébrés, CNRS EP2028, Université Pierre et Marie Curie et Ecole Normale Supérieure, Paris, France. olivaux@biologie.ens.fr
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D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins; D003400:Astacoidea / Q000378:metabolism*; D005088:Exocrine Glands / Q000378:metabolism; D005123:Eye; D007447:Invertebrate Hormones / Q000096:biosynthesis / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D020033:Protein Isoforms / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational
D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; C015947:hyperglycemic hormone, crustacean; D007930:Leucine