A Thapsigargin-Sensitive Ca2+ Pump Is Present in the Pea Golgi Apparatus Membrane1
A Thapsigargin-Sensitive Ca2+ Pump Is Present in the Pea Golgi Apparatus Membrane1
复制标题
豌豆高尔基体膜中存在对毒胡萝卜素敏感的 Ca2 泵1
DOI：
10.1104/pp.002055
复制
发表时间：
2002
期刊：
影响因子：
7.4
通讯作者：
A. Orellana
中科院分区：
文献类型：
--
作者：
Viviana R. Ordenes;Francisca C. Reyes;D. Wolff;A. Orellana
高尔基体在动物细胞和酵母（Saccharomyces cerevisiae）中表现为真正的Ca2+储存；然而，尚不清楚这种细胞器是否在植物细胞中起类似的作用。在这项工作中，我们研究了植物细胞高尔基体中活跃的Ca2+积累机制的存在。为此，我们测量了从黄化豌豆（Pisum sativum）上胚轴伸长区分离的亚细胞组分中的Ca2+摄取。使用蔗糖梯度分离细胞器表明，atp依赖性Ca2+摄取活性的分布与高尔基体标记酶木葡聚糖-聚焦转移酶之间存在很强的相关性。该活性的动力学参数为：最大Ca2+摄取速率为2.5 nmol mg min - 1， Ca2+表观K m为209 nm。钒酸盐（抑制剂浓度50%抑制[I50] = 126 μm）和环吡唑酸（I50 = 0.36 nmol mg protein - 1）强烈抑制atp依赖性Ca2+摄取，钙调素（1 μm）对atp依赖性Ca2+摄取没有刺激作用。纳米摩尔浓度的Cd2+和Cu2+抑制了Ca2+的吸收，而Mn2+、Fe2+和Co2+对Ca2+的吸收没有显著影响。有趣的是，活性钙摄取被thapsigargin（表观I50 = 88 nm）所抑制，thapsigargin是一种著名的内质网和高尔基肌-内质网Ca2+ atp酶的抑制剂。在花椰菜（Brassica oleracea）富含高尔基蛋白的部分中也检测到对高尔基蛋白敏感的Ca2+摄取活性，表明其他植物也可能具有对高尔基蛋白敏感的Ca2+泵。据我们所知，这是植物Ca2+泵活性的第一份报告，显示对低浓度的thapsigarin敏感。
The Golgi apparatus behaves as a bona fide Ca2+ store in animal cells and yeast (Saccharomyces cerevisiae); however, it is not known whether this organelle plays a similar role in plant cells. In this work, we investigated the presence of an active Ca2+accumulation mechanism in the plant cell Golgi apparatus. Toward this end, we measured Ca2+ uptake in subcellular fractions isolated from the elongating zone of etiolated pea (Pisum sativum) epicotyls. Separation of organelles using sucrose gradients showed a strong correlation between the distribution of an ATP-dependent Ca2+ uptake activity and the Golgi apparatus marker enzyme, xyloglucan-fucosyltransferase. The kinetic parameters obtained for this activity were: the rate of maximum Ca2+ uptake of 2.5 nmol mg min−1 and an apparent K m for Ca2+ of 209 nm. The ATP-dependent Ca2+ uptake was strongly inhibited by vanadate (inhibitor concentration causing 50% inhibition [I50] = 126 μm) and cyclopiazonic acid (I50 = 0.36 nmol mg protein−1) and was not stimulated by calmodulin (1 μm). Addition of Cd2+ and Cu2+ at nanomolar concentration inhibited the Ca2+ uptake, whereas Mn2+, Fe2+, and Co2+ had no significant effect. Interestingly, the active calcium uptake was inhibited by thapsigargin (apparent I50 = 88 nm), a well-known inhibitor of the endoplasmic reticulum and Golgi sarco-endoplasmic reticulum Ca2+ ATPase from mammalian cells. A thapsigargin-sensitive Ca2+ uptake activity was also detected in a cauliflower (Brassica oleracea) Golgi-enriched fraction, suggesting that other plants may also possess thapsigargin-sensitive Golgi Ca2+ pumps. To our knowledge, this is the first report of a plant Ca2+pump activity that shows sensitivity to low concentrations of thapsigargin.
影响因子：
3.3
作者：
Taylor, RS;Jones, SM;Howell, KE
通讯作者：
Howell, KE
重金属对大鼠肝微粒体Ca2()-ATP酶及Ca2+隔离的影响
DOI：
--
发表时间：
1990
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Zhang,GH;Yamaguchi,M;Kimura,S;Higham,S;Kraus-Friedmann,N
通讯作者：
Kraus-Friedmann,N