Curated Optogenetic Publication Database

Abstract: Microtubules are cytoskeletal polymers that separate chromosomes during mitosis and serve as rails for intracellular transport and organelle positioning. Manipulation of microtubules is widely used in cell and developmental biology, but tools for precise subcellular spatiotemporal control of microtubules are currently lacking. Here, we describe a light-activated system for localized recruitment of the microtubule-severing enzyme katanin. This system, named opto-katanin, uses targeted illumination with blue light to induce rapid, localized, and reversible microtubule depolymerization. This tool allows precise clearing of a subcellular region of microtubules while preserving the rest of the microtubule network, demonstrating that regulation of katanin recruitment to microtubules is sufficient to control its severing activity. The tool is not toxic in the absence of blue light and can be used to disassemble both dynamic and stable microtubules in primary neurons as well as in dividing cells. We show that opto-katanin can be used to locally block vesicle transport and to clarify the dependence of organelle morphology and dynamics on microtubules. Specifically, our data indicate that microtubules are not required for the maintenance of the Golgi stacks or the tubules of the endoplasmic reticulum but are needed for the formation of new membrane tubules. Finally, we demonstrate that this tool can be applied to study the contribution of microtubules to cell mechanics by showing that microtubule bundles can exert forces constricting the nucleus.

Abstract: Microtubules are major cytoskeletal filaments that drive chromosome separation during cell division, serve as rails for intracellular transport and as a scaffold for organelle positioning. Experimental manipulation of microtubules is widely used in cell and developmental biology, but tools for precise subcellular spatiotemporal control of microtubule integrity are currently lacking. Here, we exploit the dependence of the mammalian microtubule-severing protein katanin on microtubule-targeting co-factors to generate a light-activated system for localized microtubule disassembly that we named opto-katanin. Targeted illumination with blue light induces rapid and localized opto-katanin recruitment and local microtubule depolymerization, which is quickly reversible after stopping light-induced activation. Opto-katanin can be employed to locally perturb microtubule-based transport and organelle morphology in dividing cells and differentiated neurons with high spatiotemporal precision. We show that different microtubule-associated proteins can be used to recruit opto-katanin to microtubules and induce severing, paving the way for spatiotemporally precise manipulation of specific microtubule subpopulations.