Effect of Ca2+ and Mg2+ ions on oligomeric state and chaperone-like activity of alphaB-crystallin in crowded mediaстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 11 ноября 2016 г.
Аннотация:tThe main function of small heat shock proteins acting as suppressors of aggregation of non-native proteinsis greatly influenced by crowded environment in the cell and the presence of divalent metal ions. Thegoal of the present work was to study the effects of Ca2+and Mg2+ions on the quaternary structure andanti-aggregation activity of B-crystallin under crowding conditions. We showed that Ca2+and Mg2+ionsinduced formation of suboligomeric forms of B-crystallin. This effect was retained in the presence ofcrowder (polyethylene glycol), although to a lesser degree. The chaperone-like activity of B-crystallinwas analyzed using heat-induced aggregation of myosin subfragment 1 (S1) at 40◦C. In the absence ofcrowding agents chaperone-like activity of B-crystallin exhibited low sensitivity to the presence of Ca2+and Mg2+ions. The addition of the crowding agents (polyethylene glycol 20000, Ficoll 70) dramaticallyincreased S1 aggregation rates and significantly depressed anti-aggregation activity of B-crystallin.Low concentrations of Ca2+(0.1 mM) and Mg2+(10 mM) partially restored the chaperone-like activityof B-crystallin in the presence of crowders. This effect was observed at relatively low values of [B-crystallin]/[S1] molar ratio, however, at [B-crystallin]/[S1] > 0.2 the stimulating effect of Ca2+becameless pronounced. These findings might indicate that under crowded cell conditions different factors,including divalent cations, can effectively modulate chaperone-like activity of protein chaperones, whichotherwise cannot properly cope with crowding-provoked accelerated rates of substrates aggregation.