Regulation of Intracellular Transport

细胞器和颗粒的细胞内运输在动物细胞中普遍存在，并具有基本的 对多种过程的重要性，如分泌，神经元信号，内膜的组织， 和细胞分裂。细胞内运输的驱动力是由结合到 在细胞表面和沿微管(MTS)和肌动蛋白细丝(AFs)移动。因为 几种类型的马达同时捆绑在同一货物上，相同的细胞器也随之移动 这两种类型的细胞骨架轨道运输事件都必须受到精确的监管，以确保 细胞器和颗粒到特定的细胞目的地，但确切的调控机制在很大程度上 未知。在这里，我们建议研究调节细胞内转运的机制。 作为一个实验系统的黑素载体。这些单元的主要功能是快速和同步 数以千计的膜结合色素颗粒的重新分布，这些颗粒聚集在细胞中心或 通过细胞质沿MTS和AFS的移动，在细胞质中均匀地重新分散 动力蛋白(聚集)、动力蛋白2和肌球蛋白V(分散)。在这些马达和 细胞骨架系统由单一的第二信使cAMP调节，并涉及蛋白质的活动。 蛋白激酶A(PKA)。PI的背景数据表明，PKA在 颜料颗粒表面有参与颜料聚集和分散的分子马达； 这些复合体被称为“调节运动单位”(RMU)。初步证据还表明，MTS和 AFS本身可能在色素运输中发挥积极作用。在这个研究项目中，生化、分子、 细胞方法将被用来检验这一假设，即多种机制参与了 黑素载体细胞内运输的调节。为了检查这些调控机制，信号 RMU的成分将被识别，它们在分子马达调节中的作用将被阐明。 细胞骨架轨迹本身的特性在调节细胞内运输中的作用将是 也下定决心。

Intracellular transport of organelles and particles is ubiquitous in animal cells and has fundamental importance for such diverse processes as secretion, neuronal signaling, organization of endomembranes, and cell division. The driving force for intracellular transport is provided by molecular motors bound to the surface of cargo organelles and moving along microtubules (MTs) and actin filaments (AFs). Because several types of motors are simultaneously bound to the same cargo and the same organelles move along both types of cytoskeletal tracks transport events have to be precisely regulated to ensure the delivery of organelles and particles to specific cellular destinations but the exact regulatory mechanisms are largely unknown. Here we propose to examine the mechanisms of regulation of intracellular transport using melanophores as an experimental system. The major function of these cells is fast and synchronous redistribution of thousands of membrane-bounded pigment granules, which aggregate at the cell center or redisperse uniformly throughout the cytoplasm by moving along MTs and AFs by means of cytoplasmic dynein (aggregation), and kinesin 2 and myosin V (dispersion). Switching between these motors and cytoskeletal systems is regulated by a single second messenger, cAMP, and involves the activity of Protein Kinase A (PKA). Background data by the PI demonstrates that PKA forms two separate complexes on the surface of pigment granules with molecular motors involved in pigment aggregation and pigment dispersion; these complexes are called "regulated motor units" (RMU). Preliminary evidence also indicates that MTs and AFs themselves may play an active role in pigment transport. In this research project biochemical, molecular, and cellular approaches will be used to test the hypothesis that multiple mechanisms are involved in the regulation of intracellular transport in melanophores. To examine these regulatory mechanisms, signaling components of RMU will be identified, and their role in the regulation of molecular motors will be elucidated. The role of the properties of cytoskeletal tracks themselves in the regulation of intracellular transport will be also determined.