Regulation of protein synthesis in Y-organs of the blue crab (Callinectes sapidus): involvement of cyclic AMP.
Paired Y-organs secrete ecdysteroid hormones that control cycles of growth and molting in crustaceans. Y-Organs are regulated, at least in part, by molt-inhibiting hormone (MIH), a polypeptide produced and released by the X-organ/sinus gland complex of the eyestalks. In the present studies, crab (Callinectes sapidus) Y-organs were incubated in vitro in the presence of [(35)S]methionine, and cyclic nucleotide analogs or experimental agents that influence the cAMP signaling pathway. In 4-hr incubations, 8-Br-cAMP and db-cAMP (but not 8-Br-cGMP) suppressed incorporation of [(35)S]methionine into Y-organ proteins; the effect of 8-Br-cAMP was concentration-dependent. Autoradiograms of radiolabeled Y-organ proteins separated on SDS-PAGE gels indicated the effect of 8-Br-cAMP was general (as opposed to selective) suppression of protein synthesis. Addition of both forskolin (an adenylyl cyclase activator) and 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor) likewise suppressed incorporation of [(35)S]methionine into Y-organ proteins. Cycloheximide (a protein synthesis inhibitor) suppressed incorporation of [(35)S]methionine into Y-organ proteins and secretion of ecdysteroids. The combined results suggest that cAMP is involved in regulation of protein synthesis in C. sapidus Y-organs. We are currently investigating the link of protein synthesis to ecdysteroid production, and the possibility of cross-talk between cAMP and other cellular signaling pathways in Y-organs.
Han
Deug-Woo
DW
Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
Patel
Nimisha
N
Douglas Watson
R
R
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001345:Autoradiography; D003386:Brachyura / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D026461:Ecdysteroids / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004702:Endocrine Glands / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D014176:Protein Biosynthesis; D015398:Signal Transduction; D013997:Time Factors
D026461:Ecdysteroids; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003994:Bucladesine; D003513:Cycloheximide; D008715:Methionine; D000242:Cyclic AMP; D006152:Cyclic GMP; D015056:1-Methyl-3-isobutylxanthine