αB-Crystallin-coated MAP microtubule resists nocodazole and calcium-induced disassembly

Abstract

contained αB-crystallin. Electron micrographs clearly showed direct interactions of purified αB-crystallin with the surface of microtubule-associated proteins (MAPs) attached to MTs. Purified αB-crystallin bound to MAPMTs in a concentration-dependent manner. However, αB-crystallin did not bind MTs reconstituted from purified tubulin. Finally, we observed that αB-crystallin increased the resistance of MTs to depolymerization in cells and in vitro. Taken together, these results suggest that one of the functions of αB-crystallin is to bind MTs via MAP(s) and to give the MTs resistance to disassembly.

α-B-Crystallin as a Tissue Marker of Epileptic Foci in Paediatric Resections

“…Chaperone proteins possess the ability to prevent target protein interactions and aggregation of misfolded proteins 14 ; they are, thereby, protective molecules during times of stress or shock. The domain of α-B-crystallin inhibits the aggregation of tubulin and other microtubuleassociated proteins in particular [15][16][17] . Decreased α-B-crystallin occurs with muscular atrophy and is associated with decreased amounts of tubulin 18 .…”

Analysis of the αB-crystallin domain responsible for inhibiting tubulin aggregation

“…For example, ␣-crystallin modulates the assembly of intermediate filament vimentin and stabilizes actin filaments in a phosphorylation-dependent manner (Nicholl and Quinlan 1994;Wang and Spector 1996). We reported that ␣B-crystallin associates with tubulin (Arai and Atomi 1997;Fujita et al 2004;Sakurai et al 2005). Previously, we reported that heat-induced denatured tubulin dimer aggregation could be suppressed by ␣B-crystallin, showing that ␣B-crystallin may bind to denatured/denatured intermediate forms of tubulins, but not to native tubulin dimers (Arai and Atomi 1997).…”

“…Previously, we reported that heat-induced denatured tubulin dimer aggregation could be suppressed by ␣B-crystallin, showing that ␣B-crystallin may bind to denatured/denatured intermediate forms of tubulins, but not to native tubulin dimers (Arai and Atomi 1997). In addition, ␣B-crystallin directly associates with the surface of microtubule-associated protein (MAP) microtubules (Fujita et al 2004). Denatured tubulin is reported to inhibit the assembly of native tubulin (Maccioni 1983).…”

Muscle plasticity related to changes in tubulin and αB-crystallin levels induced by eccentric contraction in rat skeletal muscles

“…After incubation with secondary antibodies, the membrane was incubated with an enhanced chemiluminescence kit (Amersham Biosciences Co., Buckinghamshire, UK). αB-crystallin was expressed in Escherichia coli (35) and purified by protein chromatography, and tubulin (phosphocellulose column purified tubulin) was purified from the porcine brain (13). The purified proteins (αB-crystallin, 5, 10, 20, 30, and 40 ng; α-tubulin, 1, 3, 5, 7, 9, and 11 ng) were used as standards for each protein because the relationship between the gradual contents of each purified protein and the linearity of band intensity is proportional.…”

“…Microtubules, which consist of tubulin, are associated with different fibril types depending on muscle fibers and their protein contents, and their plasticity is controlled by electrical activity (29). We previously traced these proteins to determine whether the system formed by αB-crystallin and its substrate (tubulin) responds to mechanical environmental demands resulting in morphological and biochemical responses, which lead to adaptive transformation of the skeletal muscle (13,15).…”