title: Calcium uptake and gp80 messenger RNA destabilization follows cAMP receptor down regulation in Dictyostelium discoideum.
abstract: The mechanism by which high concentrations of cAMP selectively destabilize the gp80 mRNA in Dictyostelium discoideum was investigated. This treatment which leads to down-regulation of the cAMP receptor was also found to cause an increase in calcium uptake. Given this observation, we sought a role for calcium as a second messenger in the degradation of the gp80 mRNA. Changes in the mRNA levels were examined after treating cells with compounds known to alter their intracellular Ca2+ concentrations. This included the use of A23187, Ca2+, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate HC1 (TMB-8), LiCl and 8-p-chlorophenylthioadenosine 3',5'-cyclic monophosphate (ClPhS-Ado-3':5'-P). The sum of the data suggest that it is the cAMP-induced influx of Ca2+ across the plasma membrane, as apposed to a cAMP-mediated release of Ca2+ from intracellular stores, that initiates gp80 mRNA degradation. Treatment of cells with Concanavalin A (ConA) to induce cAMP receptor down-regulation, also causes a reduction in gp80 mRNA levels and an increase in calcium uptake.
authors.affiliation: Departamento de Bioquímica, Universidade de São Paulo, Brazil.
authors.forename: G M
authors.initials: GM
authors.lastname: Souza
authors.forename: C
authors.initials: C
authors.lastname: Klein
authors.forename: J C
authors.initials: JC
authors.lastname: Maia
authors.forename: A M
authors.initials: AM
authors.lastname: Da Silva
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics*; D003208:Concanavalin A / Q000494:pharmacology; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics*; D015536:Down-Regulation; D005656:Fungal Proteins / Q000235:genetics; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D018021:Lithium Chloride / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D011953:Receptors, Cyclic AMP / Q000502:physiology*
chemical_list: D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; D011953:Receptors, Cyclic AMP; C052291:cell cohesion molecule, Dictyostelium; D003208:Concanavalin A; D000001:Calcimycin; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D018021:Lithium Chloride; D002118:Calcium