Stéphane Fievez

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ATP and GTP are hydrolyzed during self-assembly of actin and tubulin, respectively. It is known that nucleotide is hydrolyzed on the polymer in two consecutive steps, chemical cleavage of the gamma-phosphate followed by the slower release of Pi. This last step has been shown to play a crucial role in the dynamics of actin filaments and microtubules. Thus(More)
In a low ionic strength buffer and in the absence of free ATP, the interaction of G-actin (G) with myosin subfragment-1 (S1) leads to the formation of arrowhead-decorated F-actin-S1 filaments, through a series of elementary steps. The initial formation of GS and G2S complexes is followed by their condensation into short oligomers. The kinetics of formation(More)
The kinetics of interaction of monomeric pyrenyl-labeled G-actin with myosin subfragment-1 (S1 (A1) and S1(A2) isomers) has been examined in the stopped-flow at low ionic strength. The data confirm the previously reported existence of binary GS and ternary G2S complexes. The increase in pyrenyl-actin fluorescence which monitors the G-actin-S1 interactions(More)
The susceptibility of subdomain-2 of actin to different proteases has been examined, for G-actin, F-actin, G-actin-S1(A2) and F-actin-S1(A2) complexes on a comparative basis. The sites of subtilisin, alpha-chymotrypsin and trypsin attack, exposed on G-actin, are protected in F-actin, F-actin-S1(A2) as well as in the G-actin-S1(A2) complex. In contrast, a(More)
Actin filaments are major dynamic components of the cytoskeleton of eukaryotic cells. Assembly of filaments from monomeric actin occurs with expenditure of energy, the tightly bound ATP being irreversibly hydrolyzed during polymerization. This dissipation of energy perturbs the laws of reversible helical polymerization defined by Oosawa and Asakura (1975),(More)
BACKGROUND Chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVD) share risk factors and impair each other's prognosis. AIMS To assess the prevalence of airflow limitation (AL) compatible with COPD in a population at cardiovascular risk and to identify determinants of AL. METHODS All consecutive patients referred to the(More)
The kinetics and mechanism of myosin subfragment-1-induced polymerization of G-actin into F-actin-S1-decorated filaments have been investigated in low ionic strength buffer and in the absence of free ATP. The mechanism of assembly of F-actin-S1 differs from salt-induced assembly of F-actin. Initial condensation of G-actin and S1 into oligomers in reversible(More)
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