Park M K, Ashby M C, Erdemli G, Petersen O H, Tepikin A V
MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, UK.
EMBO J. 2001 Apr 17;20(8):1863-74. doi: 10.1093/emboj/20.8.1863.
We have identified three distinct groups of mitochondria in normal living pancreatic acinar cells, located (i) in the peripheral basolateral region close to the plasma membrane, (ii) around the nucleus and (iii) in the periphery of the granular region separating the granules from the basolateral area. Three-dimensional reconstruction of confocal slices showed that the perigranular mitochondria form a barrier surrounding the whole of the granular region. Cytosolic Ca(2+) oscillations initiated in the granular area triggered mitochondrial Ca(2+) uptake mainly in the perigranular area. The most intensive uptake occurred in the mitochondria close to the apical plasma membrane. Store-operated Ca(2+) influx through the basolateral membrane caused preferential Ca(2+) uptake into sub-plasmalemmal mitochondria. The perinuclear mitochondria were activated specifically by local uncaging of Ca(2+) in the nucleus. These mitochondria could isolate nuclear and cytosolic Ca(2+) signalling. Photobleaching experiments indicated that different groups of mitochondria were not luminally connected. The three mitochondrial groups are activated independently by specific spatiotemporal patterns of cytosolic Ca(2+) signals and can therefore participate in the local regulation of Ca(2+) homeostasis and energy supply.
我们已经在正常的活胰腺腺泡细胞中鉴定出三组不同的线粒体，它们分别位于：（i）靠近质膜的外周基底外侧区域；（ii）细胞核周围；（iii）将颗粒与基底外侧区域分隔开的颗粒区域的周边。共聚焦切片的三维重建显示，颗粒周围的线粒体形成了围绕整个颗粒区域的屏障。在颗粒区域起始的胞质Ca(2+)振荡主要在颗粒周围区域触发线粒体Ca(2+)摄取。最强烈的摄取发生在靠近顶端质膜的线粒体中。通过基底外侧膜的储存式Ca(2+)内流导致Ca(2+)优先摄取到质膜下线粒体中。核周线粒体通过在细胞核中局部解除Ca(2+)的笼闭而被特异性激活。这些线粒体可以隔离细胞核和胞质的Ca(2+)信号。光漂白实验表明，不同组的线粒体在管腔上没有连接。这三组线粒体通过胞质Ca(2+)信号的特定时空模式独立激活，因此可以参与Ca(2+)稳态和能量供应的局部调节。
