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Protein synthesis in presynaptic endings from squid brain: Modulation by calcium ions
Author(s) -
Claudio Benech Juan,
Crispino Marianna,
Kaplan Barry B.,
Giuditta Antonio
Publication year - 1999
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19990315)55:6<776::aid-jnr12>3.0.co;2-1
Subject(s) - cytosol , bapta , thapsigargin , chemistry , protein kinase c , calcium , calmodulin , ionomycin , biophysics , calphostin c , microbiology and biotechnology , biochemistry , biology , kinase , intracellular , enzyme , organic chemistry
Previous biochemical, autoradiographic, and ultrastructural data have shown that, in the synaptosomal fraction of the squid optic lobe, protein synthesis is largely due to the presynaptic terminals of the retinal photoreceptor neurons (Crispino et al. [1993a] Mol. Cell. Neurosci. 4:366–374; Crispino et al. [1993b] J. Neurochem. 61:1144–1146; Crispino et al. [1997] J. Neurosci. 17:7694–7702). We now report that this process is close to its maximum at the basal concentration of cytosolic Ca ++ , and is markedly inhibited when the concentration of this ion is either decreased or increased. This conclusion is supported by the results of experiments with: 1) compounds known to increase the level of cytosolic Ca ++ , such as A23187, ionomycin, thapsigargin, and caffeine; 2) compounds sequestering cytosolic calcium ions such as BAPTA‐AM; and 3) agents that block the role of Ca ++ as second messenger, such as TFP and W7, which inhibit calmodulin, and calphostin, which inhibits protein kinase C. We conclude that variations in the level of cytosolic Ca ++ induced in presynaptic terminals by neuronal activity may contribute to the modulation of the local synthesis of protein. J. Neurosci. Res. 55:776–781, 1999. © 1999 Wiley‐Liss, Inc.