Observing Microtubule End-Binding Proteins Fused to mKusabira Orange Fluorescent Protein at 60X Magnification
The ends of microtubules are in a constant dynamic state as the continuous addition or removal of tubulin proteins alters the length of the biopolymers. The rate of depolymerization is different for each end according to its polarity, and the terminus that grows the fastest is considered the positive end while the other, more stable terminus, is termed the negative end. The fast-growing portion of the microtubule is composed of beta-tubulin projected outwards toward the membrane of the cell. The alpha-tubulins stabilize their structure in the region near the nucleus at one of the centrioles located in the centrosome. In the digital videos presented above, normal Gray fox lung fibroblast cells (FoLu line) are observed expressing monomeric Kusabira Orange fused to the microtubule end-binding protein, EB3.