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Inhibition of cyclic GMP formation and aggregation in Dictyostelium by the intracellular Ca 2+ antagonist TMB‐8
Author(s) -
Europe-Finner G.N.,
Newell P.C.
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80511-6
Subject(s) - dictyostelium discoideum , chemotaxis , intracellular , extracellular , dictyostelium , egta , microbiology and biotechnology , receptor , chemistry , cell membrane , cell surface receptor , biophysics , biochemistry , cell , biology , calcium , organic chemistry , gene
Aggregation in Dictyostelium discoideum was shown in previous studies employing EGTA to require Ca 2+ , but the intra‐ or extracellular site of action of this ion and its role in chemotaxis were not determined [1]. In this investigation we show that the intracellular Ca 2+ immobilising agent TMB‐8 does not affect binding of the signalling nucleotide, cAMP, to the cell surface receptors but abolishes the rapid accumulation of intracellular cGMP and subsequent chemotactic aggregation. We infer that movement of Ca 2+ from membrane‐bound stores is triggered by binding of cAMP to the cell‐surface receptor and that this plays a primary role in stimulating cGMP formation and chemotaxis.