Image: Deformed cilia can lead to a host of diseases and conditions in the human body because of a problem related to their assembly, which requires the translocation of vast quantities of the vital cell protein tubulin. University of Georgia researcher Julie Craft and assistant professor Dr. Karl Lechtreck have published a study that shows the mechanism behind tubulin transport and its assembly into cilia, including the first video imagery of the process. An interdisciplinary team from the UGA Franklin College of Arts and Sciences and the College of Engineering collaborated on the research, which used total internal reflection fluorescence microscopy to analyze moving protein particles inside the cilia of Chlamydomonas reinhardtii, a green alga widely used as a model for cilia analysis. The team exploited the natural behavior of the organism—which is to attach by its cilia to a smooth surface, such as a microscope glass cover. This positions the cilia within the 200-nanometer reach of the total internal reflection fluorescence microscope allowing for the imaging of individual proteins as they move inside the cilia. The video was published along with the study and is available as a podcast at http://jcb.rupress.org/site/biosights/biosights_jan_19_2015.xhtml. “This is the first time it has been shown directly, through live imaging, that IFT does function as a tubulin pump,” said Lechtreck. “Being able to see tubulin moving into cilia allowed for first insights into how this transport is regulated to make sure cilia will have the correct size.” “Unicellular models are great tools to address the many fundamental questions which remain unanswered such as controlling the size of cilia and how cells determine the proteins to be placed into these sensory organelles. In Chlamydomonas, we can initiate cilia formation experimentally, which allows us to see cilia during construction and analyze protein traffic while they are made.” The new findings are expected to have wide implications for a variety of diseases and conditions related to cilia defects in the body. Additional study co-authors include Peter Kner, Aaron Harris, and Sebastian Hyman. Tubulin transport by IFT is upregulated during ciliary growth by a cilium-auton…
