TY - JOUR
T1 - Kinetics and nucleotide specificity of a surface cAMP binding site in Dictyostelium discoideum, which is not down-regulated by cAMP
AU - Ments-Cohen, Martine van
AU - Genieser, Hans-Gottfried
AU - Jastorff, Bernd
AU - Haastert, Peter J.M. van
AU - Schaap, Pauline
N1 - Relation: http://www.rug.nl/gbb/
date_submitted:2007
Rights: University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute
PY - 1991/7/15
Y1 - 1991/7/15
N2 - Dictyostelium cells exhibit four types of kinetically distinct surface cAMP binding sites, the A(H), A(L), B(S), and B(SS) sites, which are down-regulated during persistent stimulation with cAMP. Although most cAMP-induced responses are subject to desensitization during constant stimulation, some responses, notably the induction of post-aggregative gene expression, require persistent cAMP stimulation. The kinetics and specificity of residual cAMP-binding activity in cells treated for 4 h with micromolar cAMP were investigated. It was found that around 4000 rapidly dissociating binding sites per cell with an affinity of about 300 nM are retained after down-regulation. The nucleotide specificity of the remaining sites was very similar, but not completely identical to the A(H), A(L) and B sites, suggesting that these sites belong to the same class of cell surface cAMP receptors and may be utilized to mediate responses requiring continuous cAMP stimulation.
AB - Dictyostelium cells exhibit four types of kinetically distinct surface cAMP binding sites, the A(H), A(L), B(S), and B(SS) sites, which are down-regulated during persistent stimulation with cAMP. Although most cAMP-induced responses are subject to desensitization during constant stimulation, some responses, notably the induction of post-aggregative gene expression, require persistent cAMP stimulation. The kinetics and specificity of residual cAMP-binding activity in cells treated for 4 h with micromolar cAMP were investigated. It was found that around 4000 rapidly dissociating binding sites per cell with an affinity of about 300 nM are retained after down-regulation. The nucleotide specificity of the remaining sites was very similar, but not completely identical to the A(H), A(L) and B sites, suggesting that these sites belong to the same class of cell surface cAMP receptors and may be utilized to mediate responses requiring continuous cAMP stimulation.
KW - CAMP RECEPTOR
KW - DOWN-REGULATION
KW - CYCLIC NUCLEOTIDE SPECIFICITY
KW - DEPENDENT PROTEIN-KINASE
KW - CYCLIC-AMP
KW - UNPROTECTED NUCLEOSIDES
KW - ADENYLATE-CYCLASE
KW - CELLS
KW - RECEPTOR
KW - ACTIVATION
KW - PHOSPHODIESTERASE
KW - DESENSITIZATION
KW - ACCUMULATION
U2 - 10.1111/j.1574-6968.1991.tb04831.x
DO - 10.1111/j.1574-6968.1991.tb04831.x
M3 - Article
VL - 82
SP - 9
EP - 14
JO - FEMS Microbiology Letters
JF - FEMS Microbiology Letters
IS - 1
ER -