Biophysical Society Thematic Meeting - June 28-July 1, 2015

New Biological Frontiers Illuminated by Molecular Sensors and Actuators

Poster Abstracts

25-POS Board 25 Rapidly Rewriting Tubulin Codes inside Primary Cilia Emily Su 1,2 , Takanari Inoue 2,1 , Yu Chun Lin 3,2 . 3 Institute of Molecular Medicine, Naitonal Tsing Hua Univesity, Hsinchu City, Taiwan. 1 Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD, USA, 2 Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA, Primary cilium is a microtubule-based protrusion on the apical surface of almost every cell type in our body, while functions as a sensory organelle that transduces extracellular cues to specific intracellular functions. Dysfunctions of primary cilia consequently lead to a variety of human diseases known as ciliopathies. Primary cilium is composed of a microtubule buddle called axoneme that gives support to the structure and provides a track for cilia motors-dependent movement. Axonemal tubulins undergo various post-translational modifications (PTMs) which are tightly regulated by specific modifying enzymes. Although axonemal PTMs has been known for several decades, deciphering how they regulate the structure and function of primary cilium is still largely unchartered mainly due to a lack of techniques to locally manipulate axonemal PTMs without affecting microtubule PTMs in the cell body. To overcome this long-standing challenge, we have recently developed a “chemically inducible diffusion trap” (CIDT) technique that allows us to translocate protein of interests (POIs) into primary cilia for manipulation of ciliary composition or signaling locally on a second timescale. With this technique, we translocated PTMs modifying enzymes specifically to axoneme for local perturbation of tubulin PTMs in cilia. Accumulation of one deglutamylase, cytoplasmic carboxypeptidase 5 (CCP5), to axoneme by our CIDT system can efficiently deglutamylate axonemal PTMs in cilia. This novel approach enables us to evaluate the specific roles of axonemal PTMs in the structural integrity and function of primary cilia and to understand how cilium gets organized and regulates itself by axonemal PTMs.

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