Cytoskeletal organization in animal and plant cell types is quite different. and plant cell types is quite different. While the mechanical properties of animal cells and their shape integrity rely mainly on a dense network of Carbamazepine cortical actin, interphase MTs are much less abundant and are involved in intracellular vesicle trafficking during interphase (25, 26). Conversely, plant cells display a dense network of cortical MTs that is involved in cell wall synthesis (11, 27). The actin cytoskeleton in plant cells is mostly found within more central regions of the cytoplasm, notably within cytoplasmic strands that cross the vacuole and connect to the nucleus (28). In addition, plant cells lack centrosomes, which leads to diffuse MT nucleation within the cell (plants. Tissue shape-derived mechanical stresses were shown to play a dominant role in organizing the MTs in these cases (23, 24). Because of the coupling between mechanical stress and tissue geometry, the role of cell geometry alone on cytoskeletal organization can be difficult to estimate when working at the tissue level. Due to their high flexural rigidity and persistence length of the order of a few millimeters (29), MTs are rigid over cellular dimensions and can be expected to align along their long axes if constrained in specific geometries. However, many models predicted that MTCMT interactions influence the ability of alignment (30C34), and the alignment along the longest axis hypothesis remains to be tested root-derived callus cells were digested to make spherical protoplasts. Protoplasts were then plated on top of the microwell array. (axis of the image, which is parallel to the long axis of the rectangular shapes and parallel to one of the sides for the other shapes. Open in a separate window Fig. 2. Effect of the shape on the MT network organization. (= 44 and number of repeats = 12 for triangles, = 48 and = 10 for rectangles, = 38 and = 11 for squares, = 26 and = 7 Carbamazepine for circles, and = 22 and = 4 for controls. (and number of repeats are the same as in = 50 repeats, and = 50 repeats, and = 40 and number of repeats = 11 for triangles, = 40 and = 12 for rectangles, = 34 and = 12 for squares, = 22 Rabbit polyclonal to ZNF75A and = 3 for circles, = 40 and = 2 for controls. (values of KS test are provided as an indication, ns for values of 0.05. The number of protoplasts and number of repeats are the same as in and and values of 10?7, 10?4, 0.02, or 0.05 for rectangular, triangular, squares, and circular shapes, respectively; and and value Kuiper = 10?16). The anisotropy of the MT network in elongated shapes is also significantly higher than for the control, suggesting that the MTs are better aligned to one another in the elongated shapes (Fig. 2value, KS test = 10?7; and and and Fig. S7). MTs are not allowed to cross the boundary domain. When using parameter values extracted from experiments or previous modeling studies (and and Table S1), the 3D model with severing leads to alignment of the MT Carbamazepine network with the long axis in rectangular shapes (Fig. 2 and and and 0.05 with Kuipers test; 0.05; and value Kuiper = 8 10?6). Moreover, the anisotropy of the actin network in rectangular shapes is significantly higher than for the control shape, suggesting that the actin filaments are better aligned to one another in the rectangular shapes (Fig. 3value KS = 3 10?4; (Fig. 4= 19/20), whereas in the mutant more than one-third of the cells exhibited an average angle higher than 20 (= 10/26) and some cells had a dominating transverse array of MTs (= 5/26) (Fig. 4and and 0.05). Open in a separate window Fig. 4. Shape response in protoplasts with genetically disturbed MTs dynamics. (mutation background ((green) protoplasts in rectangular microwells (square markers) and in control-shaped (circle markers). Number of protoplasts = 19 and number Carbamazepine of repeats = 3.