Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India.
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India.
J Theor Biol. 2023 May 21;565:111466. doi: 10.1016/j.jtbi.2023.111466. Epub 2023 Mar 15.
Molecular motors are responsible for carrying cellular transport of various membranous vesicles or organelles along cytoskeletal tracks. Transport of cellular cargos require high forces that are generated by motors working in groups. Hence, the properties of cargo transport can be modulated by varying various parameters such as cargo size and shape, microtubule geometry, motor number and their arrangement on cargo surface. Only those motors which are present in the contact zone on cargo surface have potential to bind to microtubule. Although earlier studies revealed the importance of cargo size, total motors attached to microtubule and their arrangement on cargo transport, yet how the contact zone influences binding of motors to microtubule largely remains unexplored. Here, it has been shown that contact zone is elliptical in shape for a spherical cargo and increases with cargo size for Kinesin-1 motors. To further understand the combined effect of elliptical contact zone and microtubule geometry on cargo transport, 3D mean-field model with uniform and clustered arrangement of motors for different cargo sizes and motor number has been used. Our findings indicate that cylindrical microtubule geometry maximizes the microtubule-bound motors which enhances the runlength and velocity of cargo transport. Our results show that microtubule-bound motors decrease with cargo size for uniform arrangement of motors on cargo thus decreasing its runlength and velocity, whereas in clustered arrangement, the number of microtubule-bound motors increase with cargo size which leads to increase in runlength and velocity.
分子马达负责沿着细胞骨架轨道携带各种膜泡或细胞器的细胞运输。细胞货物的运输需要由协作工作的马达产生的高力。因此，货物运输的特性可以通过改变货物的大小和形状、微管的几何形状、马达的数量及其在货物表面的排列等各种参数来调节。只有那些存在于货物表面接触区域的马达才有与微管结合的潜力。尽管早期的研究揭示了货物大小、附着在微管上的总马达数量及其在货物运输中的排列对货物运输的重要性，但接触区域如何影响马达与微管的结合在很大程度上仍未得到探索。在这里，已经表明对于球形货物，接触区域呈椭圆形，并且随着货物尺寸的增加而增加，对于 Kinesin-1 马达也是如此。为了进一步了解椭圆形接触区域和微管几何形状对货物运输的综合影响，使用了具有均匀和聚集排列的马达的 3D 平均场模型，用于不同的货物尺寸和马达数量。我们的研究结果表明，圆柱形微管几何形状使结合在微管上的马达最大化，从而提高了货物运输的运行长度和速度。我们的结果表明，对于货物表面上马达的均匀排列，结合在微管上的马达随着货物尺寸的增加而减少，从而降低了其运行长度和速度，而在聚集排列中，结合在微管上的马达数量随着货物尺寸的增加而增加，从而导致运行长度和速度的增加。
