Donato R, Battaglia F, Cocchia D
Institute of Anatomy, Medical School, Perugia, Italy.
Cell Calcium. 1987 Aug;8(4):299-313. doi: 10.1016/0143-4160(87)90005-4.
The ability of S-100 proteins to inhibit the assembly of brain microtubule proteins (MTPs) in the presence of microM levels of Ca2+ increases as a function of pH. This seems to be due to an increasingly larger inhibitory effect of S-100 on the nucleation and, probably, on the elongation of microtubules (MTs) as the pH raises. In the presence of microM Ca2+ levels, the ability of S-100 to disassemble MTs also increases linearly with the pH, suggesting that the larger inhibitory effect of S-100 on MTP assembly at alkaline than at acidic pH may depend on both a decrease in the assembly rate and an increase in the disassembly rate. Also, S-100 inhibits the assembly of phosphocellulose-purified tubulin to a larger and larger extent as the pH raises. S-100 brings about its effect on MT assembly-disassembly probably by sequestering soluble tubulin, though additional mechanisms cannot be excluded. The present data are briefly discussed in relation to the role attributed to changes in intracellular pH in the regulation of the state of assembly of cytoplasmic MTs.
在微摩尔水平的Ca2+存在下，S-100蛋白抑制脑微管蛋白（MTPs）组装的能力随pH值升高而增强。这似乎是由于随着pH值升高，S-100对微管（MTs）成核以及可能对微管延长的抑制作用越来越大。在微摩尔水平的Ca2+存在下，S-100拆解MTs的能力也随pH值呈线性增加，这表明S-100在碱性pH下比在酸性pH下对MTP组装具有更大抑制作用，可能既取决于组装速率的降低，也取决于拆解速率的增加。此外，随着pH值升高，S-100对磷酸纤维素纯化的微管蛋白组装的抑制作用越来越大。S-100可能通过螯合可溶性微管蛋白对MT组装-拆解产生影响，不过也不能排除其他机制。本文简要讨论了这些数据与细胞内pH值变化在调节细胞质MT组装状态中所起作用的关系。
