Trimeric G proteins in crustacean (Callinectes sapidus) Y-organs: Occurrence and functional link to protein synthesis

Academic Article

Abstract

  • Crustacean Y-organs produce ecdysteroid molting hormones. Regulation of ecdysteroidogenesis appears to be complex, involving regulatory ligands (including but not limited to molt-inhibiting hormone, an eyestalk neurohormone) and the capacity of the Y-organs to respond to those ligands. Available data indicate cell signaling pathways involving cAMP, cGMP, or both may be involved in regulation of Y-organ function. Trimeric G proteins link receptor occupancy to regulation of intracellular cAMP levels. In studies reported here, we have assessed the occurrence of G proteins in blue crab (Callinectes sapidus) Y-organs, and the link of G proteins to Y-organ function. Bacterial toxin-catalyzed ADP-ribosylation revealed a PTX-sensitive (α - like) protein in Y-organ membranes, but failed to reveal a CTX-sensitive (α -like) protein in Y-organ membranes. Western blotting with primary antibodies raised against conserved regions of mammalian G proteins detected an α -immunoreactive protein (≈40 kDa) and two α -immunoreactive proteins (≈50 and ≈57 kDa) in Y-organ membrane preparations. Incubation of Y-organ membrane fractions with cholera toxin significantly suppressed incorporation of [ S]-methionine into TCA-precipitable Y-organ proteins, but had no detectable effect on ecdysteroidogenesis in short-term (6 h) incubations. The combined results indicate that C. sapidus Y-organs possess both G and G proteins, and that α is functionally linked to regulation of glandular protein synthesis. © 2005 Wiley-Liss, Inc. i s i s i s s 35
  • Digital Object Identifier (doi)

    Author List

  • Han DW; Watson RD
  • Start Page

  • 441
  • End Page

  • 447
  • Volume

  • 303
  • Issue

  • 6