I didn’t pay enough attention to primary cilia in my earlier years, and that is one of life’s big regrets (well, regret is a strong word). They are very fascinating little sensory organelles, and the thought of primary cilia carrying the weight of neuron migration on their little basal body shoulders is impressive. Check out today’s image, from a paper showing the role of primary cilia in brain development.
Neurons are frequently born far from their final home in the brain, and this migration is key to healthy nervous system development and function. A recent paper shows the importance of primary cilia in the migration of interneurons (neurons that connect one neuron to another) in the cerebral cortex. Primary cilia are microtubule-based sensory organelles that project out of a cell’s membrane. Higginbotham and colleagues imaged migrating interneurons in the developing cerebral cortex and found a correlation between primary cilia dynamics and interneuron mobility. This process requires the ciliary protein Arl13b, a GTPase in the Arf/Arl family. Arl13b ensures correct localization and movement of guidance cue receptors in primary cilia. In the images above, interneurons (green chamber in cartoon, green cells in images) migrate along tracks toward a signal secreted by dorsal cortical cells (blue chamber in cartoon). The migration of Arl13b mutant interneurons (right panel) was drastically reduced when compared to control interneurons (left, same scale).
Higginbotham, H., Eom, T., Mariani, L., Bachleda, A., Hirt, J., Gukassyan, V., Cusack, C., Lai, C., Caspary, T., & Anton, E. (2012). Arl13b in Primary Cilia Regulates the Migration and Placement of Interneurons in the Developing Cerebral Cortex Developmental Cell, 23 (5), 925-938 DOI: 10.1016/j.devcel.2012.09.019
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