October 3, 2011

Behind every great mobile organelle is an equally awesome motor protein. The motor proteins dynein and kinesin move cargo along microtubules, and play crucial roles in countless cellular processes. A recent paper shows how these two motors cooperate.

The fungus Ustilago maydis grows into long hyphal cells in laboratory culture. Their use in cell biology is powerful, as their length and motor transport is reminiscent of human neurons. These long cells grow from the cell tip and have similarly oriented microtubules at either end of the cell. In the middle of the cell, microtubules overlap with opposite polarity. The polarity of these microtubules is important – dynein motors walk to one end of microtubules (the “minus” end), while most kinesin motors walk to the other (the “plus” end). A recent paper looked at how these two motors cooperate with each other in the motility of early endosomes in U. maydis cells. Schuster and colleagues found that while dynein is important for short-range motility, kinesin is important for long-range transport through the antipolar microtubule array in the center of the cell. Top image above shows the elongated hyphal cell with the nucleus in red. Bottom image shows the growth of microtubules by showing two consecutive time-points of EB1 (red then green), which is a protein found on the tips of growing microtubules. The two different insets show the antipolar growth of microtubules at the center (left inset), compared with the growth of similarly-oriented microtubules near the cell tip (right inset).

ResearchBlogging.orgSchuster, M., Kilaru, S., Fink, G., Collemare, J., Roger, Y., & Steinberg, G. (2011). Kinesin-3 and dynein cooperate in long-range retrograde endosome motility along a nonuniform microtubule array Molecular Biology of the Cell, 22 (19), 3645-3657 DOI: 10.1091/mbc.E11-03-0217

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