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Interaction of the Two Structural Domains of Calmodulin with Mature and Immature Rat Brain Microtubules
Author(s) -
Passareiro Heloisa,
Erneux Christophe,
Nunez Jacques
Publication year - 1990
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1990.tb04956.x
Subject(s) - calmodulin , microtubule , tubulin , microtubule associated protein , neurite , microbiology and biotechnology , biochemistry , amino acid , biophysics , inhibitory postsynaptic potential , biology , chemistry , enzyme , neuroscience , in vitro
The inhibitory effect of calmodulin on the assembly of mature and immature rat brain microtubules was compared with that of the two major structural domains of this protein, the COOH‐terminal fragment (amino acids 78–148) and the NH 2 ‐terminal fragment (amino acids 1–77), to determine the calmodulin structural domain responsible for the inhibitory effect on microtubule assembly. Microtubules prepared during the early stages of brain development, i.e., during intensive neurite outgrowth, are more sensitive to inhibition by the Ca 2+ ‐calmodulin complex than those obtained from adult brain. Significant inhibition of immature microtubule assembly was observed with both fragments in the absence of Ca 2+ , but the effects were more important when Ca 2+ was present. With adult brain microtubules, the two fragments remained without effect on assembly in the absence of Ca 2+ , whereas some inhibition was seen in its presence but only with the COOH‐terminal polypeptide. Under all these conditions, the COOH‐terminal fragment was always more active than the NH 2 ‐terminal fragment on microtubule polymerization, albeit to a lesser extent than native calmodulin.