Control of microtubule assembly-disassembly by calcium-dependent regulator protein.

Abstract

The Ca2+-dependent regulator (CDR) protein of cyclic nucleotide phosphodiesterase is a low molecular weight, acidic, Ca2+-binding protein which has been implicated in a number of Ca2+ dependent enzymatic functions. Indirect immunofluorescence has revealed that CDR is specifically associated with the chromosome-to-pole region of the mitotic apparatus during metaphase-anaphase in a pattern distinctly different from that of similar cultured cells stained with anti-

Differential phosphorylation of MAP-2 stimulated by calcium-calmodulin and cyclic AMP.

“…Examination of calcium sensitivity of cold labile microtubules demonstrated that calmodulin concentrations severalfold in excess of that of tubulin were required for disassembly (15). I now show that a calcium-and calmodulin-dependent protein kinase with broad substrate specificity can phosphorylate MAP-2.…”

NMDA Receptor Activation Suppresses Microtubule Growth and Spine Entry

“…Studies in detergentextracted cells showed that microtubules polymerize at low calcium concentrations, whereas increasing calcium concentrations to the micromolar range directly induced microtubule disassembly (Fuller and Brinkley, 1976;Schliwa, 1976). These effects have been hypothesized to be mediated by calcium-dependent regulators of microtubule assembly, such as the abundant neuronal protein calmodulin (Marcum et al, 1978;Schliwa et al, 1981;Lee and Wolff, 1982;Deery et al, 1984). A recent report furthermore suggests that posttranslational modifications that are associated with microtubule stability, such as glutamylation, are regulated by synaptic activity (Maas et al, 2009).…”

Immunocytochemical localization of calmodulin and a heat-labile calmodulin-binding protein (CaM-BP80) in basal ganglia of mouse brain.

“…Ca"-transport in erythrocytes (15) and sarcoplasmic reticulum (18), phosphorylation of synaptic and cell membranes (30,31), and the disassembly of microtubules (26). The mode of action of calmodulin on these systems has not been established .…”