Mechanisms of organelle transport and capture along proplatelets during platelet production
Mechanisms of organelle transport and capture along proplatelets during platelet production
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DOI：
10.1182/blood-2005-06-2206
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发表时间：
2005-12-15
期刊：
影响因子：
20.3
通讯作者：
Italiano, JE
中科院分区：
文献类型：
--
作者：
Richardson, JL;Shivdasani, RA;Italiano, JE
巨核细胞通过将其细胞质重塑为长长的前血小板延伸部分来生成血小板，这些延长部分充当了生产血小板的装配线。血小板的包装和释放在每个原血小板的末端结束。在这一过程中，重要的是细胞器和血小板特异性颗粒在新生血小板中的分布。为了研究细胞器进入假定的血小板的机制，监测了细胞器/颗粒的分布和动态。单个细胞器从细胞体被送到前血小板，在那里它们双向移动，直到它们在前血小板末端被捕获。移动速度约为0.2微米/分钟，但停顿和方向变化频繁。在任何给定的时间，大约30%的细胞器/颗粒都在运动。肌动蛋白毒素不会减少细胞器的运动，泡状结构与微管密切相关。因此，运动似乎涉及基于微管的力量。细胞器的双向运动是通过原血小板内微管的双极组织来传递的，因为运动蛋白包被的珠子在渗透性前血小板的微管阵列上双向运动。细胞器沿原血小板的运动包括两种机制：细胞器沿微管运动，连接的微管相对运动。这些研究表明，形成血小板的成分被运送到原血小板，并沿着原血小板重新组装。
Megakaryocytes generate platelets by remodeling their cytoplasm into long proplatelet extensions, which serve as assembly lines for platelet production. Platelet packaging and release concludes at the tips of each proplatelet. Essential in this process is the distribution of organelles and platelet-specific granules into the nascent platelets. To investigate the mechanism of delivery of organelles into putative platelets, the distribution and dynamics of organelles/granules was monitored. Individual organelles are sent from the cell body to the proplatelets where they move bidirectionally until they are captured at proplatelet ends. Movement occurs at approximately 0.2 mu m/ min, but pauses and changes in direction are frequent. At any given time, approximately 30% of organelles/granules are in motion. Actin poisons do not diminish organelle motion, and vesicular structures are intimately associated with the microltubules. Therefore, movement appears to involve microtubule-based forces. Bidirectional organelle movement is conveyed by the bipolar organization of microtubules within the proplatelet, as kinesin-coated beads move bidirectionally on the microtubule arrays of permeabilized proplatelets. Movement of organelles along proplatelets involves 2 mechanisms: organelles travel along microtubules, and the linked microtubules move relative to each other. These studies demonstrate that the components that form platelets are delivered to and assembled de novo along proplatelets.