Jonathon Howard
Yale University
Editor, Biophysical Journal
What are you currently working on that excites you?
I’m interested in all things microtubules. Several years ago, we got fascinated by dendrite morphogenesis because the growth and shrinkage of the terminal dendrites in a growing arbor looks just like the dynamic instability of microtubules, discovered many years ago by Tim Mitchison and Marc Kirschner. We found that, just as the dynamic instability of microtubules explores and fills intracellular space, the dynamic instability of dendrites is a rapid, economical way to fill extracellular space with a dense, branched network, crucial for the high connectivity of the brain. We are now pushing the limits of resolution and sensitivity to visualize the dynamics of single microtubules and actin filaments in the tips of growing dendrites of living flies. We continue our interest in ciliary motility (how are the dynein motors coordinated?) and in the lattice-mediated regulation of the microtubule cytoskeleton (how does the severase spastin remove tubulin from the lattice?).
What have you read lately that you found really interesting or stimulating (a paper, a book, science or not science)?
I recently came across a fascinating paper on the branching properties of the trachea of ants (Aitkenhead, I. J., et al. 2020. Tracheal branching in ants is area-decreasing, violating a central assumption of network transport models. PLoS Comput. Biol. https://doi.org/10.1371/journal.pcbi.1007853). The authors show that, unlike branched neurons or mammalian airways, in which the total cross-sectional area is conserved or even increases distally across branch points, the total area decreases dramatically in ant trachea (measured in 18 different species!). They argue that this is an adaptation for the rapid removal of carbon dioxide from the tissue, which is more critical than the delivery of oxygen to the mitochondria—a beautiful example of metabolism shaping morphology!