Tension and compression in the cytoskeleton of PC-12 neurites. II: Quantitative measurements.

作者：T J Dennerll, Harish Chandra Joshi, V L Steel, Robert E. Buxbaum, S R Heidemann · 发表于：The Journal of Cell Biology · 年份：1988 · DOI：10.1083/jcb.107.2.665 · 被引用次数：289 · 研究领域：Cellular Mechanics and Interactions、Microtubule and mitosis dynamics、3D Printing in Biomedical Research

We assessed the mechanical properties of PC-12 neurites by applying a force with calibrated glass needles and measured resulting changes in neurite length and deflection of the needle. We observed a linear relationship between force and length change that was not affected by multiple distensions and were thus able to determine neurite spring constants and initial, nondistended, rest tensions. 81 out of 82 neurites showed positive rest tensions ranging over three orders of magnitude with most values clustering around 30-40 mu dynes. Treatment with cytochalasin D significantly reduced neurite rest tensions to an average compression equal to 14% of the former tension and spring constants to an average of 17% of resting values. Treatment with nocodazole increased neurite rest tensions to an average of 282% of resting values but produced no change in spring constant. These observations suggest a particular type of complementary force interaction underlying axonal shape; the neurite actin network under tension and neurite microtubules under compression. Thermodynamics suggests that microtubule (MT) assembly may be regulated by changes in compressive load. We tested this effect by releasing neurite attachment to a polylysine-coated surface with polyaspartate, thus shifting external compressive support onto internal elements, and measuring the relative change in MT polymerization using quantitative Western blotting. Neurons grown on polylysine or collagen without further treatment ha...